ISSN 1310-8271 том 19, книга 2, 2013 Volume 19, Book 2, 2013
Transcript of ISSN 1310-8271 том 19, книга 2, 2013 Volume 19, Book 2, 2013
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ISSN 1310-8271
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,
19, 2, 2013
OF THE TECHNICAL UNIVERSITY - SOFIA
PLOVDIV BRANCH, BULGARIA
Volume 19, Book 2, 2013
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Journal of the Technical University Sofia
Plovdiv branch, Bulgaria
Fundamental Sciences and Applications Vol. 19, Book 2, 2013
International Conference Engineering, Technologies and System
TECHSYS 2013
BULGARIA
EDITORIAL BOARD
:
. ..., ... EDITOR-in-chief
Prof. Marin Nenchev, DSc
Eng., DSc Phys., PhD
. -
SCIENTIFIC SECRETARY
Assoc. Prof. Bogdan Gargov, PhD
EDITORS
1. . - 1. Prof. Sonia Tabakova, PhD
2. . - 2. Prof. Michail Petrov, PhD
3. . - 3. Prof. Angel Vachev, PhD
4. . - 4. Prof. Andon Topalov, PhD
5. . - 5. Prof. Dimitar Katsov, PhD
6. . - 6. Prof. Grisha Spasov, PhD
7. . - 7. Prof. Angel Zumbilev, PhD
EDITORIAL BOARD
1. . - 1. Prof. Angel Vachev, PhD
2. . . . ... 2. Prof. Venelin Zhivkov, DSc
3. . ... 3. Prof. Georgi Andreev, DSc
4. . ... 4. Prof. Georgi Totkov, DSc
5. . ... 5. Prof. Emil Nikolov, DSc
6. . ... 6. Prof. Ivan Iachev, DSc
7. . - 7. Prof. Marin Hristov, PhD
8. . - 8. Prof. Ognian Nakov, PhD
9. . ... 9. Acad. Nikola Sabotinov DSc
10. . ... 10. Prof. Marc Himbert DSc
11. . ... 11. Prof. Yasser Alayli DSc
12. . ... 12. Prof. Tinko Eftimov DSc
13. . ... 13. Acad. Yuriy Kuznietsov DSc
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Copyright 2013 by Technical University - Sofia, Plovdiv branch, Bulgaria. ISSN 1310 - 8271
Journal of the Technical University Sofia
Plovdiv branch, Bulgaria
Fundamental Sciences and Applications Vol. 19, Book 2, 2013
International Conference Engineering, Technologies and System
TECHSYS 2013
BULGARIA
CONTENTS
1 YURIY KUZNIETSOV, HAMUEYLA GERRA, ANGEL POPAROV
GENETICMORPHOLOGICAL APPROACH TO CREATING ANDFORECASTING THE DEVELOPMENT OF CLAMPING MECHANISMS FOR
ROTATING PARTS (PLENARY REPORT-PAPER)
7
2 ABDULKAREEM A.WAHAB ALBIHIGE ......
DESIGN AND FLOW ANALYSIS IN CENTRIFUGAL PUMP15
3 ABDULKAREEM JALIL KADHIM, AHMED WALEED HUSSEIN .. THREE-DIMENSIONAL UPPER BOUND AND FINITE ELEMENT SOLUTIONS FOR
FORWARD EXTRUSION OF RHOMBOIDAL AND SQUARE SECTIONS FROM ROUND
BILLETS THROUGH STREAMLINED DIES
21
4 ALEKSANDAR OSMANLI, ATANAS ILIEV EMPLOYEE-BRAND RELATIONSHIP RESEARCH IN MACEDONIAN
TELECOMMUNICATION COMPANY
29
5 AMIR HOSSEIN DAEI SORKHABI, MAHTALA RASAEI, SOHEILA RAFEI NUMERICAL STUDY OF THICKNESS EFFECT ON RESIDUAL STRESS IN 304L
STAINLESS STEEL WELDED PLATES
35
6 ANGELINA POPOVA, MIHAI CHRISTOV, ALEXEI VASILEV, ANTONINA DJAMBOVA, TODOR DELIGEORGIEV ...
IMPEDANCE STUDY OF QUATERNARY AMMONIUM DIBROMIDES AS ACID
CORROSION INHIBITORS
41
7 ANTONIA LAZAROVA . PRACTICAL AND APPLIED IMPLEMENTATION OF DYNAMIC STATISTICAL
METHODS IN ONLINE BASED QUESTIONNAIRE FOR RESEARCH OF THE
IMPACT OF THE MAIN STRATIFICATIONAL FACTORS ON CONSUMER
BEHAVIOUR IN BULGARIA
45
8 ANTONIO ANDONOV, ZOYA HUBENOVA, VLADIMIR GERGOV ... ANALYSIS OF HUMAN FACTORS IN AUTOMATED CONTROL SYSTEMS
49
9 BONCHO ALEKSANDROV .. IT OUTSOURCING FEATURES AND DEVELOPMENT TRENDS
55
10 BORYANA DIMITROVA, BOYAN IVANOV, DRAGOMIR DOBRUDHZALIEV, NIKOLAY STOYANOV .
OPTIMAL SYNTHESIS AND MANAGEMENT ON SUPPLY CHAIN OF BIODIZEL PRODUCTION AND DISTRIBUTION IN BULGARIA
59
11 BOYCHO BOCHEV ... MARKETING CHANNELS IN TIMES OF ECONOMIC TURBULENCE
65
12 CHAVDAR PASHINSKI, ROUMEN KAKANAKOV, LILYANA KOLAKLIEVA ... SUPERHARD nc-(Al1-xTix)N/a-Si3N4 GRADIENT NANOCOMPOSITE COATINGS FOR
MACHINING TOOLS
71
13 CONSTANTIN ROTARU, MATEI GABRIEL PERICLE, AMADO STEFAN .. AN ANALYTICAL EVALUATION OF NONLINEAR AIRFOIL CHARACTERISTICS FOR
HELICOPTER ROTOR BLADE
77
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14 DANIEL DELCHEV, NIKOLAY TONTCHEV .. RELATION BETWEEN THE COEFFICIENT OF WORKABILITY AND THE TYPE OF
MATERIAL FOR PROCESSING STEELS WITH SWARF-FORMATION
83
15 DECHKO RUSCHEV, DIMITAR KATSOV, STILIYANA TANEVA . COMPUTER-BASED AUTOMATED SYSTEM FOR PNEUMATIC TYRES
CHARACTERISTICS DETERMINATION
89
16 DECHKO RUSCHEV, RAYCHO RAYCHEV, DEYAN ZHELEV .. HYDRAULIC STAND FOR TESTING AUTOMOTIVE SHOCK ABSORBERS
95
17 DELYANA DIMOVA .. STUDYING THE DYNAMICS OF THE AVERAGE SALARY AND EMPLOYEES BY
ECONOMIC ACTIVITIES
101
18 DIMITAR DECHEV, NIKOLAI IVANOV, PETER PETROV . OBTAINING AND STUDYING THE PROPERTIES OF ALUMINIUM THIN FILMS
105
19 DIMITAR KATSOV, STILIYANA TANEVA, PEPO YORDANOV, DECHKO RUSCHEV HYDRAULIC SYSTEM FOR TESTING OF PNEUMATIC WHEELS
109
20 DIMITAR STOYANOV .. CURRENT -VOLTAGE CHARACTERISTIC OF A PHOTO RESISTANSE. A PLANE CASE
115
21 DIMO CHRISTOZOV, KIRIL KOLIKOV, BOGDAN GARGOV ... MODELING OF STRATIFICATION IN LIQUID DISPERSE SYSTEMS AT RIGHT AND
OPPOSITE SEDIMENTATION
119
22 DIMO ZAFIROV, HRISTIAN PANAYOTOV UAV RESEARCH AND DEVELOPMENT IN THE PLOVDIV BRANCH OF TECHNICAL
UNIVERSITY-SOFIA (A SURVEY)
123
23 GENNADY MAKLAKOV, PETAR GETSOV . FORCE FEATURES OF THE USE IN THE INFORMATION AND EDUCATIONAL SPACES FOR PREPARATION OF YOUNG SCIENTISTS IN THE AEROSPACE TECHNOLOGIES
129
24 GEORGI P. PASKALEV NONLOCAL BOUNDARY VALUE PROBLEM IN THE CYLINDRICAL DOMAIN - THE
CASE WHEN THE NONLOCAL CONDITION DEPENDS ON THE SPATIAL VARIABLES
135
25 GEORGI P. PASKALEV SHALOVS VARIATIONAL METHOD FOR THE MULTIDIMENSIONAL WAVE EQUATION
141
26 IMAD SHUKRY ALI, ALI HAMZAH NEAMAH .. HEAT TRANSFER ENHANCEMENT USING AIR JET / IMPINGEMENT COOLING
147
27 IVAILO BAKALOV, RUMEN STOYANOV ... MATHEMATICAL MODELING FOR VISUALIZING THE SHIP COMBUSTION ENGINE
(KDVG) - ABC, MODEL V-DZ
153
28 IVAN BARZEV, NIKOLAY ANGELOV . INVESTIGATION ON THE DEPENDENCE OF THE DEPTH OF THE MELT FROM SPEED
AND POWER DENSITY WITH LASER IMPACT ONTO ELECTRICAL STEEL
159
29 IVAN KRALOV ... METHOD FOR REDUCTION OF THE DYNAMIC LOADS AND NOISE, GENERATED IN
THE SPUR-GEAR MESHING OF CYLINDRICAL GEARS
165
30 JIVKO ILIEV, NIKOLAI IVANOV . ANALYSIS OF VIBRATIONAL STATE OF MINE CAGE FOR WINDING MACHINE IN
BABINO COAL MINE, MINE COMPLEX BOBOV DOL
171
31 KONSTANTIN METODIEV, HRISTIAN PANAYOTOV . SUBSTRATUM WATER POTENTIAL MEASUREMENTS UNDER CONDITIONS OF
INDUCED MICROGRAVITY
177
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Copyright 2013 by Technical University - Sofia, Plovdiv branch, Bulgaria. ISSN 1310 - 8271
32 MAYA MANASYAN, SERGEY MANASYAN IMPROVED DESIGN OF DRYERS MINE TYPE
183
33 MILCHO TASHEV, PAVLINKA KACAROVA, VASIL TASHEV . KINEMATIC ANALYSIS OF GEARED MECHANISM IN WATER INSTALLATIONS
187
34 MILKO ENCHEV, SVETLANA KOLEVA . PRELIMINARY DIMENSIONAL SETTING UP OF CNC LATHES
193
35 MUSA AJETI, IVAN BADEV, GEORGI KOSTADINOV . COMPOSITIONS GENERATED BY COUPLE OF CONJUGATE COMPOSITIONS IN
EVEN-DIMENSIONAL AFFINE CONNECTED SPACES WITHOUT A TORSION
197
36 NEDYALKA MARKOVA .. ASYMPTOTIC BEHAVIOR OF THE NONOSCILATORY SOLUTIONS OF DIFFERENTIOAL
EQUATIONS OF SECOND ORDER WITH MAXIMA
203
37 NELI KERANOVA, NAKO NACHEV . COVERING RADIUS OF BINARY CYCLIC CODES
209
38 NIKOLA NACHEV, STANISLAV ALEKSIEV, STOYCHO STOEV .. GENERAL TYPES OF ROTARY HYDRAULIC MACHINES
213
39 NIKOLAI ANGUELOV ..... ANALYSIS ON THE PROCESS OF DISBURSEMENTS IN OPERATIONAL PROGRAMS OF
THE EUROPEAN UNION
219
40 NIKOLAI IVANOV, DIMITAR DECHEV, PETER PETROV, POLINA MILUSHEVA .......... STUDYING MEHANICAL PROPERTIES OF TI AND CR - NI THIN FILMS
223
41 NIKOLAJ GANEV .. ABILITIES AND LIMITATIONS FOR X-RAY DIFFRACTION RESIDUAL STRESS
ANALYSIS USED IN MATERIALS SCIENCE AND MECHANICAL ENGINEERING
227
42 NIKOLAY ANGELOV ... NUMERICAL CALCULATIONS FOR DETERMINING OF INTERVALS ON AMENDMENT
OF THE POWER DENSITY ON LASER MARKING OF METALS BY MELTING AND
EVAPORATION
233
43 PETAR DASKALOV, RUMEN MITEV ... FLOW-TURNING USING THE CNC MACHINES
237
44 PLAMEN ROGLEV, DIMO ZAFIROV ... METAMODELS FOR MULTIDISCIPLINARY DESIGN OPTIMIZATION OF UAV
241
45 RADOSTIN DOLCHINKOV, PENKA GEORGIEVA ... SPHERICAL EPY- AND HIPOCYCLOIDS FROM SPACE TOOTH GEAR
247
46 ROSSITZA SARDJEVA, TODOR MOLLOV . APPLICATION OF FREQUENCY MODULATED SCREENING IN DIGITAL
ELECTROPHOTOGRAPHY
253
47 SAMER MOHAMMED ABDULHALEEM, ALI MEERALI AL-ZAMILY, REHAB NOOR AL- KABY
EFFECT OF RADIATION HEAT TRANSFER ON THE TURBULENT NATURAL
CONVECTION AND FLOW IN A BUOYANCY-INDUCED FLOW INSIDE
PARALLELOGRAMIC ENCLOSURE
259
48 SILVIA SALAPATEVA .. ROLE OF TECHNOLOGICAL CONTROL FOR INCREASING THE RELIABILITY OF
PROCESS IN CNC MACHINE TOOLS
265
49 STANKA HADZHIKOLEVA, EMIL HADZHIKOLEV COMPASS-P AN APPROACH TO THE USE OF A CONSOLIDATED MODEL OF A CLASS
OF PROCEDURES
271
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50 STEFAN KRUSTEV ... A PHYSICAL MODEL DEMONSTRATING ACHILLES TENDON RUPTURE
277
51 STEFAN KRUSTEV ... VIRTUAL REALITY IN MEDICAL PHYSICS AND BIOPHYSICS
EDUCATION - POSSIBILITIES AND CHALLENGES
281
52 STEFAN STEFANOV, IVAN PRODANOV . STUDY OF EXPLOSION-PROOF PROPERTIES OF INDUCTIVE NEUTRALIZERS
285
53 STILIYANA TANEVA ... INVESTIGATION OF THE LATERAL SLIP OF PNEUMATIC TYRE
289
54 SVETLOZAR ASENOV, ANGELINA CHOZHGOVA .. IMPROVE ON TECHNICAL MAINTENANCE OF AIRCRAFT THROUGH MANAGING THE
OPERATIONAL RELIABILITY
293
55 SVETLOZAR ASSENOV, ANGELINA CHOZHGOVA ... TECHNICAL RESOLUTIONS FOR INCREASING EFFICIENCY OF SOURCES OF PRESSURE OF HYDRAULIC SYSTEM OF MILITARY AIRCRAFT
299
56 TANYA GIGOVA THE STATUS OF THE BULGARIAN INDUSTRY WITHIN THE FRAMEWORK OF THE
GLOBAL ECONOMIC CRISIS
303
57 TEOFIL IAMBOLIEV INTERCRYSTALLINE CORROSION OF 1.4301 AUSTENITIC STAINLESS STEEL WELD
JOINTS
309
58 TEOFIL IAMBOLIEV PROPERTIES OF STAINLESS STEEL 1.4404 (AISI 316L) GTA WELDS
315
59 TODOR TODOROV ... ANALYSIS OF SIMPLICIAL REFINEMENT STRATEGIES IN SPHERICAL TYPE DOMAINS
321
60 TONI MIHOVA, HRISTINA DAILIANOVA .. ECONOMIC RECOVERY THE EXPERIENCE OF SMALL AND MEDIUM-SIZE
ENTERPRISES IN EUROPE
325
61 TONI MIHOVA ... SMALL AND MEDIUM ENTERPRISES ECONOMIC DEVELOPMENT AND
COMPETITIVENESS
331
62 TRAYAN STAMOV PERSPECTIVES IN RESEARCH AND USING OF EMOTIONS IN CONTEMPORARY
TRANSPORT DESIGN
335
63 VAHIDEH VAHDATPANAHI SH., AMIR HOSSEIN DAEI SORKHABI, SIAMAK HAGIPOUR .
PREDICTION OF IRON RATIO IN METAL INTER GAS WELDING WITH COPPER AND BRASS WIRES USING FUZZY LOGIC MODEL
341
64 VALYO NIKOLOV . MECHANICAL MATHEMATICAL MODELING OF THE TILTING PROCESS OF LIFTING
MASTS OF FORKLIFT TRUCKS WITH LOAD
347
65 VASIL PETKOV . TRADE RELATIONS BETWEEN TAIWAN AND BULGARIA
351
66 VIARA SLAVIANSKA ... REDUCTION OF LABOR EXPENSES A STRATEGY FOR SURVIVAL IN CONDITIONS OF
CRISIS?
357
67 YURIY KUZNETSOV, SERGEY SAVITSKY, BOGDAN GARGOV, ANGEL POPAROV . WORKING MACHINE-STAND FOR THE PROCESSING OF THE POLYGONAL HOLES
363
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Copyright 2013 by Technical University - Sofia, Plovdiv branch, Bulgaria. ISSN 1310 - 8271
Journal of the Technical University Sofia Plovdiv branch, Bulgaria Fundamental Sciences and Applications Vol. 19, 2013 International Conference Engineering, Technologies and System TECHSYS 2013 BULGARIA
-
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GENETICMORPHOLOGICAL APPROACH TO CREATING AND FORECASTING THE
DEVELOPMENT OF CLAMPING MECHANISMS FOR ROTATING PARTS
YURIY KUZNIETSOV, HAMUEYLA GERRA, ANGEL POPAROV
Abstract: The problem about creating new technical schemes can be successfully solved inmodern science by using a new methodological approach which includes systematic analysis,
principles of evolution, morphological analysis, and other methods for searching technical
solutions.
In the present work problems connected with the evolution, development and synthesis of the
clamping devices (chucks) for parts with different forms are considered. Different principles and
laws of mechanics are used in the suggested classification of the interaction nature between the
clamping element and the object of clamping. Amongst them are the principle of the topological
invariance of the field sources, the symmetry principle, the principle of equality, the principle of
conservation of the basic mechanical and other transformation energy, the law of conservation of
energy, D'Alembert's principle, and the Hooke's law.
Keywords: clamping devices, clamping elements, collets chuck, power (force) flows
- 7 -
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Copyright 2013 by Technical University - Sofia, Plovdiv branch, Bulgaria. ISSN 1310 - 8271
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Kuznyetsov Yuriy Nikolaevich National Technical University of Ukraine Kyiv Polytechnic Institute 37 Prospect Peremogy, 03056 Kiev, Ukraine E-mail: [email protected] Hamueyla Gerra Agostinho Neto University Avenida 4 de Fevereiro 7 Luanda 3350, Angola E-mail: [email protected] Department of Mechanical Engineering Technical UniversitySofia, Branch Plovdiv 25 Tsanko Dystabanov St. 4000 Plovdiv BULGARIA E-mail: [email protected]
29.01.2013 .
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mailto:[email protected]://mail80.abv.bg/app/servlet/sendmess?ac=sab&[email protected]
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Copyright 2013 by Technical University Sofia, branch Plovdiv, Plovdiv, BULGARIA. ISSN 1310 - 8271
Journal of the Technical University Sofia
Plovdiv branch, Bulgaria
Fundamental Sciences and Applications Vol. 19, 2013
International Conference Engineering, Technologies and System
TECHSYS 2013
BULGARIA
DESIGN AND FLOW ANALYSIS IN
CENTRIFUGAL PUMP
DR.ABDULKAREEM A.WAHAB ALBIHIGE
Abstract: This research deals the flow analysis in the centrifugal pump and design of
centrifugal pump. Centrifugal pump is analyzed by using single stage end suction.
The research proposes a design method which may be used to evaluate the detailed of an
impeller and volute of pump. The design of a centrifugal impeller can be used the layout of the
impeller for the selected angles and areas.
The design depends upon the skill and experience of the designer for the best results. The
basic design elements necessary to define the impeller proportions. The design of centrifugal
pump involves a large number of interdependent variables so there are several possible designs
for the same design point. Specific speed is used to classify impellers on the basis of their
performance, and proporations regardless of their actual size or the speed at which they
operate.
.
Key words: impeller, volute, specific speed, head, velocity.
1. Introduction
The pump is converting of mechanical energy to
hydraulic energy of the handling fluid to get it to
required place or height by the centrifugal force of
the impeller blade. A pump transfer mechanical
energy from some external source to the fluid
flowing through it and losses occur in any energy
conversion process. [1]
The energy transferred is predicted by the
Euler equation. The kinds of loss of centrifugal
pump can be differentiated in internal losses and
external or mechanical losses. The internal losses
are hydraulic losses or blade losses by friction,
variations of the effective area or changes of
direction losses of quantity at the sealing places
between the impeller and housing at the rotary shaft
seals. The external or mechanical losses in sliding
surface losses by bearing friction or seal friction. [1]
The difference in design details is dictated
mostly by the application and mechanical
requirements. Every pump consists of two principle
parts, an impeller, and pump casing. As a result of
the impeller action, liquid leaves the impeller at a
higher pressure and higher velocity than exist at its
entrance. The velocity is partly converted into
pressure by the pump casing before it leaves the
pump through the discharge nozzle. This conversion
of velocity into pressure is accomplished either in a
volute casing or in a diffusion casing of the pump.
[2]
The choice of a suitable flow path for a
centrifugal impeller is almost prerequisite for
completely defining the entire passage geometry.
The boundary values of the relative velocity
components are known from the inlet and outlet
velocity vector diagrams (analysis carried out
assuming zero prewhirl) which resulted from the
previous preliminary design stage. For a specified
value of the impeller length along its axis of
rotation a desirable total relative velocity schedule
is prescribed. The choice is mainly based on
achieving acceptable uniform rate of diffusion. [4]
2. Specific speed (Ns&Nsm)
Specific speed is very useful parameter for
engineers involved in centrifugal pump design and
For application. For the pump designer an intimate
knowledge of the function of specific speed is
the only road to successful pump design. For the
application, specific speed provides a useful means
of evaluating various pump lines. For the user
specific speed is a tool for use in comparing various
pumps and selecting the most efficient and
economical pumping equipment for his plant
application.
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Specific speed is always calculated at the best
efficiency point with maximum impeller diameter
and single stage only, there are two formula of
specific is:
Nsm = (1)
Which is calculated the base of operating
conditions (rpm, m3/s, and m). And the other
formula of specific speed is:
Ns=3.65 (2)
Which is calculated the base of operating
conditions (rpm, 0.075 m3/s, m). The equations
1&2 shows that a fixed value of the specific speed
described all operating conditions ( N ,Q ,and N )
that can be satisfied by similar pumps . This
physical significance of equations 1 &2 is also the
most useful definition for the specific speed itself.
Although it has thus been demonstrated that
the specific speed can be presented in different
forms, all these expressions have the same physical
significance, any fixed value of the specific speed
describes a combination of operating conditions that
permits similar flow conditions in geometrically
similar pumps. [6
For the practical application of the concept of
specific speed, it is equally important to consider
the physical significance of differences in specific
speed. From the given definition, it follows that
operating conditions of different specific speeds
cannot be satisfied by similar pumps with similar
flow conditions, i.e., any change in specific speed
definitely requires a corresponding change in the
geometric form of the pump and/or in the flow
conditions. This important relation between the
specific speed and the geometric design of the
pump. [6]
3. Flow analysis
Two- dimensional models for centrifugal or
radial pump begin with analysis of the flow in a
radial cascade (Fig.1).There exist simple conformal
mappings that allow potential flow solutions for
linear cascade to be converted into solutions for the
corresponding radial cascade flow, though the
proper interpretation of these solution requires
special care. The resulting head/flow characteristics
for frictionless flow in a radial cascade of infinitely
this logarithmic spiral blade. [3]
Potential flow solution in which the vorticity is
zero. This solution would be directly applicable to
static or nonrotating radial cascade in which the
flow entering the cascade has no component of the
voracity vector in the axial direction. This would be
the case for a nonswirling axial flow that is a
deflected to enter a nonrotating, radial cascade in
which the axial velocity is zero.
But, relative to a rotating radial cascade, such an
inlet flow does have vorticity, specifically a
vorticity with magnitude 2 and a direction of
rotation opposite to the direction of rotation of the
impeller.
Consequently, the frictionless flow through the
impeller is not irrotational, but has a constant and
uniform vorticity -2.The rotation solution has no
through flow, but simply consists of rotation of the
fluid within each blade passage, as sketched in Fig.
(2). [3].
Fig. 1. Schematic of the radial cascade
Fig. 2. A sketch of the displacement component of
the inviscid flow through a rotating
radial cascade. [3]
4. Slip factor and incidence loss
In the derivation of Euler's pump equation it is
assumed that the flow follows the blade. In reality
this is, however, not the case because the flow angle
usually is smaller than the blade angle. This
condition is called slip. Nevertheless, there is close
connection between the flow angle and blade angle.
An impeller has endless number (infinite) blades
which are extremely thin, and then the flow lines
will have the same shape as the blades. When the
flow angle and blade angle are identical, then the
flow is blade congruent. [5]
The flow will not follow the shape of the
blades completely in a real impeller with a limited
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Copyright 2013 by Technical University Sofia, branch Plovdiv, Plovdiv, BULGARIA. ISSN 1310 - 8271
number of blades with finite thickness. The
tangential velocity out of the impeller as well as the
head is reduced due to this. When designing
impellers, we have to include the difference
between flow angle and blade angle. This is done by
including empirical slip factors in the calculation of
the velocity triangles. It is important to emphasize
that the slip is not a loss mechanism but just an
expression of the flow not following the blade. [5]
Incidence loss occurs when there is a
difference between the flow angle and blade angle
at the impeller or guide vane leading edges, as
shown in Fig.(3).
Fig. 3. Velocity triangles where indicates the
velocity with slip. [5]
A recirculation zone occurs on one side of the blade
when there is difference between the flow angle and
the blade angle. [5]
The recirculation zone causes a flow contraction
after the blade leading edge. The flow must once
again decelerate after the contraction to fill the
entire blade channel and mixing loss occurs as
shown in Fig. (4a).
At off-design flow, incidence losses also occur
at the volute tongue. The designer must therefore
make sure that the flow angles and blade angles
match each other so the incidence loss is
minimized. Rounding blade edges and volute casing
tongue can reduce the incidence loss. The
magnitude of the incidence loss depends on the
difference between relative velocities before and
after the blade leading edge and is calculated using
the following model (pfleiderer 1990).
Hloss,incidence = (3)
Where, is empirical value which is set to
0.5 to 0.7 depending on the size of the recirculation
zone after the blade leading edge, and Ws is
difference between relative velocities before and
after the blade edge using vector calculation, as
shown in Fig.(4b).
Fig. 4a. Incidence loss at inlet to impeller.
Fig. 4b. Nomenclature for incidence loss model. [5]
Incidence loss is alternatively modeled as a
parabola with minimum at the best efficiency point.
The incidence loss increases quadratically with the
difference between the design flow and the actual
flow, as shown in Fig. (5).
Fig. 5. Incidence loss as function of the flow.
The centrifugal force creates a secondary vortex
movement because of the difference in rotation
velocity between the fluid at the surface of the
impeller and the fluid at the pump, as shown in
Fig.6
The secondary vortex increases the disk friction
because it transfers energy from the impeller
surface to the surface of the pump casing.
Fig. 6. Disk friction on impeller.
5. Procedure of design
Firstly, must be chose the design parameters for the
pump, head, discharge, rpm. We are taken the
values for these parameters: Q = 0.0167 m3/s, H =
- 17 -
-
70m, speed = 2900 rpm, liquid = water, Entry =
one, Stage = one.
1. Specific speed (Ns &Nsm )( equation 1
and equation 2)
The values of Ns for centrifugal pump with one
entry suction and with one stage are (40 300).
2. Volumetric efficiency (Q):
There is empirical equation for calculate Q
Q = (4)
3. Inlet discharge (Q'):
Q'= (5)
4. Diameter of inlet pipe (Do):
Do = Ko (6)
Ko is coefficient, the values of it from 3.5 to 6.5.
5. Velocity of liquid at the inlet pipe (Co):
Co = (7)
= (8)
is coefficient, the values of it from 0.06
to 0.08
6. Diameter of impeller at inlet (D1):
D1 =0.8Do to Do (9)
7. Hydraulic efficiency (H):
There is empirical equation for calculate
the H ,
H = 1 - (10)
Do in mm
8. Mechanical efficiency (m):
There are two types of mechanical
efficiency:
(8.1) Internal mechanical efficiency (mi):
There is empirical equation for
calculate mi
mi = (11)
(8.2) External mechanical efficiency (me):
This loss is due to coupling, bearing, and
sealing, and difficulty for estimate the value of
this efficiency, therefore assume the value of it
from 0.96 to 0.98.
Therefore, m = mi me (12)
9. Total (overall) efficiency (t):
t = Q H m (13)
10. Output power (Po):
Po= Q H = g Q H (14)
11. Input power (Pi):
Pi= (15)
12. Power of motor (Pm):
Pm = from 1.1Pi to 1.2Pi (16)
13. Diameter of shaft (d):
d= (17)
Mt is Tensional moment, is tensile stress
Mt =9950 (18)
Pmax in kW
The values of from 300X105 to 500X10
5
14. Diameter of hub (dB):
dB =from 1.2d to1.5d (19)
15. Meridian velocity of liquid before inlet of
impeller ( ):
= Co (20)
Meridian velocity of liquid after inlet of
impeller ( Cm1):
Cm1= k (21)
K1 is coefficient of constraint at inlet, the
values of k1 from 1.1 to1.2
17. Blade width of impeller at inlet (b1):
b1= (22)
18. Peripheral velocity of impeller at inlet ( u1):
U1= (23)
19. Angle of blade at inlet ( 1L):
The blade angle at inlet 1L is bigger than the
flow angle at inlet 1 , from the velocity diagram at
inlet (assume there is no prewhirl of flow at inlet)
that is mean, there is no inlet guide vanes, i.e. 1 =
90o , C1 = Cm1
tan 1 = (24)
1L = 1 + (25)
is angle of attack; the values of it are from 3o
to 8o.
20. Relative velocity of liquid at inlet of impeller
(W1):
From velocity triangle,
W1 = (26)
21. Peripheral velocity of impeller at outlet (u2):
u2 = (27)
is head coefficient, the values of it are from
o.45 to 0.65
22. Diameter of impeller at outlet (exit) (D2):
D2 = (28)
23. Meridian velocity of liquid at outlet of
impeller ( ):
= from 0.7 to (29)
24. Tangential component of absolute velocity
for liquid at outlet (Cu2):
Cu2 = u2 u2 (30)
25. Slip factor ( ): The slip is the difference between the
theoretical tangential components of absolute
velocity of liquid and the actual tangential
component of absolute velocity, because there is
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-
Copyright 2013 by Technical University Sofia, branch Plovdiv, Plovdiv, BULGARIA. ISSN 1310 - 8271
difference between the angles 2&2L .
= 1 - = 1 (31)
26. Meridian velocity of liquid before outlet of
impeller (Cm2):
Cm2 = k (32)
K2 is coefficient of constaint at outlet; the
values of it are from 1.05 to 1.1
27. Angle of blade at outlet (2L):
Sin2L = . . sin1L (33)
Chose the value of from Fig. (7) according
the value of Ns
Fig. 7. Relation between w1/w2 and Ns [7]
28. Width of blade at outlet ( b2):
b2 = (34)
29. Number of blades of impeller (z):
Z = 6.5 sin (35)
30. Pitch of blades at inlet of impeller (t1):
t1 = (36)
31. Pitch of blades at outlet of impeller (t2):
t2 = (37)
32. Thickness of blade at inlet measure on the
circle of radius r1( 1):
k1 = (38)
33. Thickness of blade at inlet measure on the
middle line (1):
1 = 1sin 1L (39) 34. Thickness of blade at outlet measure on the
circle of radius r2( 2):
K2 = (40)
35. Thickness of blade at outlet, measure on the
middle line (2):
2 = 2 sin 2L (41)
36. Capacity Coefficient ():
= (42)
37. Head coefficient ():
= (43)
38. Net positive suction head required (NPSHr):
NPSHr = 0.001046 N3/4 Q2/3 (44)
39. Suction specific speed (Nss):
Nss= (45)
40. Diameter of inside of volute ( D3):
D3 = kH D2 (46)
KH is coefficient, estimated it by the values
of Ns.
41. Width of volute at inlet (b3):
b3 = b2 + (0.02 to 0.05) D2 (47)
42. Average velocity of liquid at volute (Cum):
Cum = kcum (48)
Kcum is coefficient, the values of it depends
on the values of Ns.
43. Design of Volute:
Athr = (49)
In which, Athr is throat area of volute; Cthr is
velocity of liquid at throat.
From Law of free vortex,
= C (50)
In Which C is constant of free vortex, the
value of C 0.9
r4 r2 + t + rthr (51)
t is thickness of tongue of volute.
Av = Athr . (52)
In which Av is the annulus area between the
impeller and outer diameter of volute for each
angle v ( v from zero to 360)
Cthr = . u2 (53)
Fig. 8. Nomenclatures of volute. [8]
- 19 -
-
Fig. 9. Relation between the values of Cthr/u2 and
Ns.
Av=Athr , r , rv = r3 + r
ro = rv + r
r is the radius of annular area between the
impeller and the outside diameter of volute
for each angle.
rv is the radius of center to the center of
annular area for each angle.
ro is outside radius of volute for each angle.
6. Conclusions:
1. In design flow, the wake or boundary layer on
the suction surface may be quite thin, but as the
flow coefficient is decreased, the increased
incidence leads to large wakes. Clearly, the
nonuniformity of the discharge flow implies on
effective slip due to these viscous effects.
2. The slip will not only depend on the geometry
of the blades but will also be a function of the
flow coefficient and the Reynolds number.
3. The design of centrifugal pump is difficult
subject, because the designer firstly must be
know and understand deeply the hydrodynamic
fundamentals of the centrifugal pump and
know becarfully the importance each
component of the pump.
4. The impeller of the pump is heart of the pump,
therefore the requirements for design of it is
very important.
5. The design of pump does not depend on thetheoretical relation only, but it depends on the
experience of the designer in the field of
application of the pumps, and also the design
depends on the experimental and empirical
relations. In these relations, there are various
coefficients and factors, the designer must be
choosing the correct values of them and in the
suitable ranges.
REFERENCES
1. Khin cho Thin, Mya Khaling, and Khin
Manng Aye (Design and performance Analysis of
centrifugal pump).World Acadency of Science,
Engineering and Technology 46 1946.
2. A.J.Stepanoff, PhD (Centrifugal and Axial
Pump)2nd
Edition 1957.
3. Christopher Earls Brennen (Hydrodynamic of
pumps). Concepts NREC 994.
4. Sarim Al-Zubaidy (Preliminary of Design of
centrifugal impellers using optimization
Techniques).Transations of the ASME, Journal
of fluids engineering, June 1994, vol.116.
5. GRUNDFOS, Researches and Technology, the
centrifugal pump 2005.
6. George F. Wislicenus (Fluid mechanics of
Turbomachinery) First Edition 1947.
7. Zlatariv (Turbopumps and Fans) Technical/
Sofia 1998.
8. J.Karassik ( Centrifugal pumps ) 1998
Department of Mechanical Engineering
University of Babylon / College of
Engineering
Hilla City
Iraq
e-mail: [email protected]
13.02.2013 .
- 20 -
mailto:[email protected]
-
Journal of the Technical University Sofia
Plovdiv branch, Bulgaria
Fundamental Sciences and Applications Vol. 19, 2013
International Conference Engineering, Technologies and System
TECHSYS 2013
BULGARIA
1. Introduction:
Extrusion is a metalworking process, in
which the raw material is forced through a die to
produce long, straight, semi-finished metal products
such as bars, solid and hollow sections, tubes, wires,
and strips .Non-symmetric extrusion means that
both the deformation process and outgoing product
is unsymmetrical in shape about the central axis and
mostly used to produce shaped sections in industry
such as square sections, L-shape, T-shape U-shape.
In extrusion, mechanical properties of the material,
frictional condition at the toolworkpiece interface,
extrusion ratio and die profile, are among the
important parameters that significantly affect the
desired characteristics of the product [1]. the
optimization of these parameters has been one of the
most important tasks attention of many researchers.
Extrusion die profile can be conical or curved. In
the past, due to the difficulty in manufacturing of
non-conical dies, most of research works concerned
with the optimization of rod extrusion die geometry,
focused on conical dies, such as that performed by
Avitzur [2] on the optimization of die angle by the
upper bound method. Nowadays, by use of
computer numerical control (CNC) machines, and
therefore, the case of manufacture of complex die
shapes, many pieces of research work have been
performed on the optimization of curved die
profiles. Chen and Ling [3] gave upper bound
solutions to axisymmetric extrusion problems; they
used three basic kinds of axisymmetric curved dies,
namely, the cosine, elliptical and the hyperbolic
types and transformation techniques used in order to
achieve a mathematically consistent analysis.
D.Y.Yang, C.M.Lee and J.H.Yoon [4] are used
finite element method to extrude the shape function
through curved dies. Lee et al. [5] designed the
optimal die profile for hot rod extrusion that could
yield more uniform microstructure. Nagpal and
Altan [6] presented new die designs, which had
curved surfaces and improved the upper bound on
extrusion pressure. In fact, the shape of the die
designed by theses authors was so good that it was
THREE-DIMENSIONAL UPPER BOUND AND FINITE
ELEMENT SOLUTIONS FOR FORWARD EXTRUSION OF
RHOMBOIDAL AND SQUARE SECTIONS FROM ROUND
BILLETS THROUGH STREAMLINED DIES
ABDULKAREEM JALIL KADHIM, AHMED WALEED HUSSEIN
Abstract: The increasing interest in the modeling of metal-forming processes in recent years has
brought the development of different analytical and/or numerical technique. In this paper, upper
bound and finite element solution are made for a steady-state three-dimensional extrusion of
rhomboidal and square sections through a streamlined dies to predict the required power and to
show the stresses and strains distribution in the die and billet through the extrusion process . A new
method of die surface representation using blending function, and trigonometric relationships, is
proposed by which smooth transitions of die contour from the die entrance to the die exit are
obtained. The upper bound extrusion pressure is obtained based on derived a general velocity felid.
The effects of area reduction, the optimum relative die length, the shape of stream function and
frictional conditions are also discussed. The results are in a good agreement with that obtained by
other research workers.
Keywords: Upper bound method; Finite element; Simulation; Streamlined dies; Extrusion process.
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-
used in many other works to come. Gunasekera and
Hoshino [7] used upper bound solution for extrusion
of polygonal sections from bound billet through
converging and curved dies .Kiuchi et. al. [8]
introduces a new concept in the upper bound
analysis of extrusion and drawing of shape sections
where the rotational and axial velocity component
were approximately assumed. However, there are
very few reports of 3-D mathematical and FEM
models deals the extrusion of rhomboidal and
square sections from round billet throughout
streamlined dies so, in this paper, a 3-D upper
bound mathematical model and FEM simulation by
ANSYS software will consider in order to show the
effect of die length, area reduction, friction factor on
total relative extrusion pressure and also the stresses
and strain distributions throughout the extrusion
process.
2. Velocity Fields:
Figure (1) shows the schematic diagram of
the shape and dimensions of the general die in
cylindrical co-ordinate systems in which the y-
direction is coincident with the extrusion axis.
When the cross sectional shapes of both the
entrance and exit of the die are given by analytical
functions and , then intermediate
sectional contour can be blended as
follows:
------ (1)
The streamline function f(y) is given by:
------- (2)
(3)
Equation (3) satisfies the condition of zero slopes at
entrance and exit of the die respectively. The
boundary limits for the die surfaces are given by:
Therefore, Eq.(1) becomes,
(4)
For the exit rhombus section shown in
Fig.(2) let, (2w1) is the length of the rhombuss
diagonal that coincident with x-axis, (2w2) is
the length of the rhombuss diagonal that
coincident with y-axis, (DR) is the ratio of the
vertical to the horizontal diagonals
,and let (Ro) is the radius of the billet.
Figure (2) shows that when (=45o or DR=1), the
rhombus section has perpendicular sides hence, the
square sections are special case from rhombus
sections when DR=1.Due to the similarity of the die
about the x and -y axis, the first quarter will be
considered .Assuming that the sector AB is
gradually transferring to the straight line CD when
changes from 0 to , hence, the equation of exit
straight line is given by,
(5)
By knowing that x=r cos() and y=r sin() then the
last equation becomes:
(6)
From the trigonometric relationships, we note that:
(7)
By the comparison with Eq.(6), hence Eq.(6)
becomes:
(8)
Where:
the function that describes the exit section of
the die.
(In rad)
Hence, the surface equation of the die that
describes the extrusion the Rhomboidal sections
from the round billets i.e. Eq.(4),becomes,
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-
(9)
Fig. 2. First quarter of the die.
Figure (3) shows the final die surface which drawn
in MATLAB 7.11 when area reduction
60%,Ro=20mm, L/Ro=1 and DR=0.8.
Fig. 3. The die surface.
Throughout this analysis, the following assumptions
are employing [8, 10, and 11]:
i. The work material i.e. the billet material is
isotropic and homogeneous and the die is
assumed rigid body.
ii. The elastic strain is neglected.
iii. Effect of temperature between the round billet
and the die is neglected and the process is
assumed isothermal.
iv. The longitudinal velocity, Vy, is uniform at each
cross-section of the material in the die.
v. The Von-Misses yield criterion is assumed
applicable.
vi. The rotational velocity component
is expressed as product of two functions as
follows:
(10)
The condition of volume constancy in cylindrical
co-ordinate system is expressed by next equation:
(11)
From here, the velocity fields equations are derived
as:
(12)
(13
(14)
Where vo is the billet velocity and is the angle of
symmetry.
3. The Strain Rates:
According to cylindrical co-ordinate system,
the strain rates components are defined as follows
[8,9]
(15)
Total effective strain rate according to Von-Misses
criterion is given by
(16)
4. Upper Bound Solution:
The upper bound formulation is described as
follows:
- 23 -
-
(17)
Where:
and,
Here, J1 is the work dissipated for internal
deformation; 0 is the yield stress in uniaxial
tension. J2 is the work dissipated at surfaces of
velocity discontinuity at the entrance and exits of
the die respectively due to change in metal velocity.
In this analysis this power will vanish because f(y)
has zero slop at inlet and exit of the die respectively,
J3 is the work dissipated due to friction at the die-
workpiece interface and is a friction factor. In
order to find the power losses due to plastic
deformation J1 and power losses against the friction
J3, the Gauss quadrature method used to evaluate the
above volume and area integrals. Finally the relative
extrusion pressure can be written as:
(18)
5. Finite Element Simulation:
The finite element method (FEM) is a
numerical approach by which a set of partial
differential equations can be solved approximately.
FEM modeling a body by dividing it into an
equivalent system of smaller bodies or units (finite
elements) interconnected at points common to two
or more elements (nodal points or nodes) and / or
boundary lines and/or surfaces is called
discretization . In the finite element method, instead
of solving the problem for the entire body in one
operation, we formulate the equations for each finite
element and combine them to obtain the solution of
the whole body. In this research the finite element
code ANSYS (V11) was used. It is powerful
software used to solve both linear and nonlinear
problems in engineering. Many steps are required to
build the geometrical model:
A- Solid model creation: - Solid model built by
using key points, lines, areas and volumes .In
this research the key points were determined by
using MATLAB 7.11 ANSYS interface.
B- Defining element type: - The Solid billet, the
die, and the container are all modeled by using a
3-D 20-node tetrahedral structural solid element,
named as SOLID95. It can tolerate irregular
shapes without as much loss of accuracy also it
has plasticity, creep, stress stiffening, large
deflection, and large strain capabilities [18].
Contact elements, namely CONTA174 and
TARGE170, have been created between billet-
die and billet-container interfaces. Coulombs
fiction was assumed. The number of element in
the case of SOLID95 was 11282 and elements
CONTA174 and TARGE170 were 652 and 1292
respectively.
C- Defining and editing the element real
constants: - The real constants are properties
that depend on the element type, such as gap
size and initial conditions...etc.
D- Material Properties for Die and Billet:- The die
is made from tool steel, which as is well-known,
has isotropic properties
.The billet material used in this simulation
is Aluminum alloy (AL) which assumed
bilinear isotropic hardening and has modulus of
elasticity (E) of 68 Gpa, tangent modulus (ET)
of 0.1 Gpa, yield stress (y) of 70.2 Mpa and
Poissons ratio of 0.3.
E- Meshing the model: Free meshing is applied
to entire model.
F- Apply Loads and obtain the nonlinear Solution: In this step, analysis type (static),
analysis options (large deformation, equation
solver, etc.), boundary conditions, and the
loading were conducted in the form of a
prescribed displacement. This was achieved in
this simulation by assuming that total
displacement of the Ram was (z =25 mm) in the
z- direction, One load step and a substep value
of 3000 with limits changing between 100 and
4000 have been employed during solution. The
entire model is shown in Fig.(5).
6. Results and Discussion:
Upper bound solution is theoretically
applied for predication of plastic deformation work
(J) for the extrusion of rhomboidal and square
sections from round billets. The numerical
calculations have been successfully performed
concerning the effect of area reduction, die length
- 24 -
-
and friction factor on the extrusion pressure and the
optimal die length. Through, in this paper, priority
is given to the analysis of the streamlines die
which produces no shear energy at inlet and outlet
of the velocity boundaries, the present method is
applicable to analyze other die profiles simply by
changing the profile function of f(y). The main
advantage of the present work is that it could easily
be applied to the extrusion of many different shapes
just by defining the entry and exit sections functions
and putting them into the general formulations.
Gunasekera and Hoshino [7] carried out similar
work for extruding the polygonal sections from
round billets. It is observed from Fig.(5) and Fig.(6)
that The relative extrusion pressure (PE/o)
decreases with increase in the relative die length
(L/Ro) up to certain optimal relative length and then
it increases. The frictional load has always an
increasing tend with relative die length, while the
deformation load gradually decreases with increase
in the relative die length. Figure (7) shows that the
extrusion pressure increases as diagonal ratio (DR)
degreases.
Fig. 4. Quarter meshed model.
The Von Misses stress and plastic strain contours,
are shown in Figs.(8: A , B ,C and D) for the cases
of DR=1 and DR=0.8 . It can be noted these figures
that the maximum values has been observed at die
exit and billet-die interface. Also it can observe in
these figures that the stresses of extrusion of
rhomboidal section are larger than the stresses of
extrusion of square section.
7. Conclusion:
Upper Bound and FEM Solution is obtained
for the Extrusion of Rhomboidal and Square
Sections from Round Billets through Streamlined
Dies. The effect of area reduction, the optimum
relative die length, the shape of die, frictional
conditions, stress and strain conditions in the die
and billet are also discussed.
Fig. 5. Comparison between the streamlined die
designed by Ref. [7] and authors.
Fig. 6. The effect of friction factor on total relative
extrusion.
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2 2.5 3 3.5 4
Re
lati
ve d
ie p
ress
ure
PE/
o
Relative die length L/Ro
80% Area Reduction,Round to Rhombus extrusion ,=0.12,DR=1
J-frictionJ-deformationJ-total (authors)J-total(Ref.[7])
0
1
2
3
4
5
6
7
0 0.5 1 1.5 2 2.5 3 3.5 4
Rel
ativ
e d
ie p
ress
ure
PE/
o
Relative die length L/Ro
Round to Rhombus , DR=1 , 40% area reduction
J,=0
J,=0.05
J,=0.1
J,=0.2
J,=0.4
J,=0.6
J,=0.8
J,=1
Billet Die Container
Punch
- 25 -
-
Fig. 7. The effect of diagonal ratio (DR) on total
relative extrusion pressure.
Fig. 8. A&C: Von Mises stress contours.
B&D:Von Mises plastic strain contours
REFERENCES
1. Laue K, Stenger H. Extrusion: processes,
machinery, tooling. Metals Park, Ohio: American
Society for Metals; (1981).
2. B. Avitzur, Metal Forming: Processes and
Analysis, McGraw-Hill, New York, 1968.
3. C.T.Chen and E.F.Ling, Upper bound solution
to axisymmetric extrusion problems Int. J.Mech.
Sci, Vol.10, PP.863-879(1968).
4. D.Y. Yang C.M. Lee and J.H. Yoon ,Finite
Element Analysis of Extrusion of Section Through
Curved Dies, Int. J. Mech. Sci. Vol.31, No.2, pp.
145-156,(1989)
5. S.K. Lee, D.C. Koo, B.M. Kim, Optimal die
profile design for uni-form microstructure in hot
extrusion, International journal Mach. Tools
Manufacture.Vol. 40 , pp.14571478,(2000).
6. V.Nagpal and T.Altan,Analysis of the three-
dimensional metal flow in extrusion of shapes with
the use of dual stream functions, Proc. 3rd
NAMRC, Canegie-Mellor Univ., Pittsburgh, Pamay
(1975).
7. J.S.Gunasekera and S.Hoshino analysis of
extrusion of polygonal sections through streamlined
dies Journal of Engineering for
Industry,vol.107/229,(1985).
8. Kiuchi M, Kish H, Ishikawa M , Study on Non
symmetric extrusion and drawing, International
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2 2.5 3 3.5 4
Rel
ativ
e d
ie p
ress
ure
PE/
o
Relative die length L/Ro
40% Area Reduction,Round to Rhombus extrusion ,=0.1
D.R.=0.6
D.R.=0.8
D.R.=1
DR=1
DR=0.8
DR=1
DR=0.8
A
B
C
D
- 26 -
-
Journal of Machine Tool, Design and Research
conference, 22nd proceedings, p. 52332,(1981).
9. C.M. Lee and D.Y. Yang and K. Lange
Numerical Analysis of Three Dimensional
Extrusion of Elliptic Sections by Method of
Weighted Residuals Int. J. Mech. Sci. Vol.31,
No.5, pp. 379-393,(1989)
10. R. Narayanasamy R. Venkatesan,upper
bound solution to extrusion of circular billet to
circular shape through cosine dies National
Institute of Technology 620 015,(2003).
11. S. Kumar and S.K. Prasad, A Finite Element
Thermal Model for Axisymmetric Cold and Hot
Extrusion using Upper Bound Technique
department of mechanical engineering, institute of
technology ,Banaras Hindu university ,Varanasi
221005,(2004)
12. Guide to the ANSYS Documentation Release
11.0.
Department of Mechanical Engineering,
University of Babylon, Babylon, Iraq.
E-mail: [email protected]
E-mail: [email protected]
14.02.2013 .
- 27 -
file:///C:/Users/User/Downloads/[email protected]:///C:/Users/User/Downloads/[email protected][email protected]
-
- 28 -
-
Copyright 2013 by Technical University Sofia, branch Plovdiv, Plovdiv, BULGARIA. ISSN 1310 - 8271
Journal of the Technical University Sofia, branch Plovdiv
Fundamental Sciences and Applications, Vol. 16, 2013
International Conference Engineering, Technologies and Systems
TechSys 2013
BULGARIA
EMPLOYEE-BRAND RELATIONSHIP
RESEARCH IN MACEDONIAN
TELECOMMUNICATION COMPANY
ALEKSANDAR OSMANLI, ATANAS ILIEV
Abstract. The purpose of the study is to examine internal branding in macedonian
telecommunication company as a high technology environment. Theoretical framework is
constructed to measure the current state of case companys employee-brand relationship.
Based on the literature review, a conclusion was made that the concepts of high technology,
internal branding and brand identity are closely connected with each other. Internal branding
is especially important for high-tech companies, because corporate brand is usually their driver
brand and every employee directly or indirectly represents the brand. At the same time, internal
branding is their biggest challenge. Brand identity, on the other hand, provides a basis for
internal branding strategy, but is also the source of brand equity for high technology
companies. Consequently, brand identity is the key concept, providing direction, depth, and
texture for the other branding dimensions.
The empirical study was conducted in a form of a quantitative questionnaire. It was found that
the level of brand knowledge and commitment in the case company was rather good, even
though certain weaknesses were identified. Based on the results, some improvement suggestions
were provided. The empirical results combined to the theoretical foundation can, thus, serve as
a preliminary groundwork for building up an internal brand management strategy for the case
company.
Key words: brands, branding, brand identity, high technology, internal branding, survey
1. Introduction
High technology companies around the
world are facing major challenges. Increasing
global competition, the accelerating pace of
technological development, the consolidation of
markets, and the increased speed with which
imitations turn up on the market have dramatically
shortened product lifecycles. As a result, it is not
enough to have efficient logistic capabilities or
unique production methods anymore; there must be
some completely new ways to make the difference
between company and ones competitors. The initial
concept of competitive advantage is getting
fundamentally new aspects as brands, instead of
products, are becoming the real source of
competitive advantage. [1]
Further, as the importance of brands and
branding is increasing, internal branding has risen
as a number one subject in the field of brand
research as well as business management [2]. So
that companies would be able to sell promises,
instead of mere products, employees should know
what they are doing and, more importantly, why
they are doing. Therefore, before selling the brands
promise to customers, companies need to sell it to
their employees.
The main assumption is that company
personnel should understand the brand meaning and
be committed to implementing it in their everyday
work. Brand in itself is a vast concept and,
therefore, the aim is to concentrate on studying the
most important branding concepts in relation to
high-tech environment as well as to dig into the
process of internal branding. To fully grasp the
issue, the following research objectives have been
set:
1. To discuss the special branding
implications of high technology environment.
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2. To identify the characteristics of internal
branding and to define the dimensions concerning
internal branding process.
3. To measure the current state of the case
company's employee-brand relationship and to
evaluate the result in relation to the theoretical
background of the study.
Branding literature has traditionally focused
on the external communication of the brand [3].
Because of this, the internal branding research is
still lacking in clear and commonly accepted
structure, although plenty of different theories about
the subject can be found. Further, the external
branding research has often concentrated on the
branding of consumer products instead of industrial
branding and, as a result, the aspects of high-
technology branding have just recently been
emerging from the branding literature.
As the research problem is clearly
connected with a practical business aspect, the
research should be conducted by adding a practical
viewpoint to the research implementation. This is
why the literature review is supported by an
empirical study collecting and combining internal
branding information in the case company.
2. Internal branding in high technology
environment
The concept of high technology has become
increasingly popular after the boom of information
technology branch in the 1990s but still it lacks a
commonly accepted definition. The general view is
that high technology industries have great
dependence on science and technology innovation
that leads to new or improved products and
services. They often have a substantial economic
impact, fueled both by large research and
development spending and a higher than industry
average sales growth. New product development
and capital investment often go hand in hand,
making high technology companies an attractive
addition to local tax bases. Traditional high-tech
industries include, for example, computer and
information technology, biotechnology, and
telecommunications. During the last five years,
however, technological innovation has created
radical changes in some industries, such as waste
management, agriculture, automotive, and oil and
gas, and these industries are increasingly being
defined as high-tech industries. [4]
One could easily think that in highly
technological markets functionality and features are
what matters, not brands. Why would successful
brand management be so important to high-tech
companies, then? First of all, a strong brand helps
attract and keep customers. Further, it can form a
solid foundation from which to launch new
products, improve relationships with channel
partners, foster good communication among
employees within and across business functions,
and help a company better focus its resources.
Unfortunately, many technology
companies, usually managed by technologists, often
lack any kind of brand strategy and believe that
market success depends primarily on the price-
performance ratio [5]. At the same time, however,
their offerings are becoming commodities
products and services are highly similar and
competitors are fast to catch up the latest
innovations [6]. As a result, in many of the high-
tech markets, financial success is no longer driven
by product innovation alone and marketing skills
and branding are playing an increasingly important
role [6]. Although the lack of managerial interest
and understanding of branding is only one example
of the special characteristics of high-tech
environment, branding high technology is much
more than just promoting the pure product.
High-tech products are sold both in
consumer and industrial markets and the main
feature distinguishing them from traditional
consumer or industrial goods are the short product
life cycles [7]. This means that the products change
rapidly over time and better and renewed versions
come to the markets quickly. The speed and brevity
of these life cycles, caused by continuous
technological advances and research and
development breakthroughs, is the main source of
high-tech branding challenges [5]. Further, the
complexity of the products and the technical
sophistication of the target market often cause
difficulties in managing the relationship with
customers, and companies may find it hard to define
what the actual target market is. Therefore, Figure 1
suggests some specific branding guidelines for
companies operating in high-tech markets to tackle
these challenges.
As discussed earlier, brand awareness
means the extent to which a brand is recognized by
(potential) customers and is correctly associated
with a particular product. Brand image, on the other
hand, is the markets perception of companys
brand identity. For high-tech the importance of
these concepts arise, because customers are
increasingly buying into brands as much as
products, and although price and performance are
essential, they do not guarantee a successful high-
tech venture.
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Copyright 2013 by Technical University Sofia, branch Plovdiv, Plovdiv, BULGARIA. ISSN 1310 - 8271
1. Establish brand awareness and a rich brand image.
2. Create corporate credibility associations.
3. Leverage secondary associations of quality.
4. Avoid overbranding products.
5. Selectively introduce new products as new brand and
clearly identify the nature of brand extensions.
Figure 1. Additional guidelines for high-tech
products
One common obstacle, however, is that
establishing positive brand awareness and brand
image requires money and time. High investments
in research and development are typical for high
technology industries [7], which often means that
marketing is running on a low budget. Investments
on branding can make a difference, though: the S
model of customer response to brand awareness
which clearly illustrates that the sales increase
incrementally as branding expenditure and,
therefore, the level of customer awareness increase,
forming an S-shaped curve.
The visibility and presence of the
organization behind a brand can create an image of
size, substance, and competence. This can hold
especially true in high-tech markets because of the
large number of small and medium size enterprises,
global orientation of the companies, and the often
complex nature of the products. The driver brand
for most technology companies is the corporate
brand, not the product brand, meaning that the
importance is on building favorable organizational
associations such as trustworthiness,
innovativeness, expertise, and quality [1]. The
whole organization should be committed to
empowering these associations, but in high-tech
especially the often visible CEO is the key
component performing an important brand-building
and communication function [5].
Customers may find it hard to judge the
quality of high-tech products, mainly because of the
technical sophistication of the products and the
possible lack of user references [1]. Leveraging
every possible positive secondary association may
help to improve the brand reputation and the
perception of product quality and, thus, reduce the
doubts that the customers possibly have. Methods
that are especially suitable in high-tech environment
are getting endorsements from top companies,
leading industry magazines, or industry experts and
gaining visibility by participating in trade shows
and seminars. Nonproduct related associations, such
as sponsorship of events or co-operation with
educational institutes, may prove to be valuable as
well.
To build a strong high-tech brand, managers
need to answer the following questions given on the
so called Brand pyramid. The pyramid consists of
five different levels, each containing strategic
questions regarding the brands tangible and
intangible characteristics (see Figure 2).
Figure 2. Brand pyramid
By answering these questions, from the
bottom to the top, managers of high-tech companies
should be able to form a solid basis for their
branding strategy.
The bottom level of the pyramid represents
the core product the tangible, verifiable product
characteristics. The tendency is moving from selling
just products to selling benefits or solutions,
which is the second level of the pyramid. Even
though this change is a step to the right direction,
the first two levels of the pyramid still represent a
product-centric point of view.
Knowing how the customers feel when
experiencing the tangible characteristics of the
offering and benefits of the brand is a key to true
differentiation and, further, provides direction and
meaning for the brand. The third level of the
pyramid represents the stage when managers
understand the importance of emotional reasons and
act accordingly. Getting to the third level of the
pyramid is already a big achievement for a company
operating in high-tech environment, but a promise-
centric business model is truly accomplished when
a company reaches the fourth and fifth stages of the
pyramid. The top two levels illustrate the idea that
powerful brands attract and hold customers with
their particular promises of value.
The fourth level describes the general
values that the brand reflects, and the fifth level
represents the personality of the brand itself. Brands
that reach the last two levels of the pyramid are,
first of all, able to generate a feasible promise of
value, consisting of functional benefits, emotional
benefits, and price. Second, the most importantly,
they are able to fulfill this promise, which gives
them a huge advantage compared to their
competitors. In short, these last two levels of the
pyramid define the relevant and differentiating
character of the brand.
LEVEL
1
LEVEL 2
What are the tangible, verifiable, objective, measurable
characteristics of products, services, ingredients, or components
that carry this brand name?
What is the
essential nature
and character of
the brand?
What does value mean for
the typical loyal customer?
What psychological rewards or emotional
benefits do customers receive by using this
brands products? How does the customer feel?
What benefits to the customer or solutions results from
the brands features?
LEVEL 3
LEVEL 4
LEVEL 5
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The fundamental difference between a
product-centric and a brand-centric company lies in
the attitudes of the people throughout the
organization. Every person in a company should
recognize the brand strategy, be committed to it,
and understand specifically how their behavior
contributes to its execution [5]. This thesis
concentrates on internal matters, but it is important
to note that the brand experience should be
consistent across all the companys partners, as
well. Technology products are often composite
systems consisting of several products or
ingredients, and the partners of a high-tech
company may be responsible for installation,
delivery or support of these products [1]. Therefore,
companies have to ensure that the experience that
customers have with each partner is coordinated and
consistent with the official brand strategy.
A strong corporate brand that will endure
over time is highly depending on the internal
understanding of corporate identity. The biggest
challenge of high-tech branding is to get everyone
in the organization to understand the importance of
branding and what it means to sell promises instead
of just products - internal branding.
Internal branding has been directly linked to
employee satisfaction, which in turn is linked to
customer satisfaction, which is, naturally, linked to
business performance (Drake et al. 2005, 34). For
this thesis, the most significant conclusions of the
theoretical foundation are the following:
1. High-tech brands build equity through a
clear and well-defined brand identity.
2. The biggest challenge of high-tech
branding is to get everyone in the organization to
understand the importance of branding and what it
means to sell promises instead of products.
3. A clearly defined brand identity is the
initial source of internal branding.
4. Getting the employees to know and care
about the brand identity is one of the most
important objectives of internal brand management.
These conclusions clearly show that the
concepts of high technology, internal branding and
brand identity are connected with each other; Figure
3 present the most relevant linkages and
relationships between these three concepts. Internal
branding is especially important for high-tech
companies because corporate brand is usually their
driver brand and every employee directly or
indirectly represents the brand. At the same time,
internal branding is their biggest challenge. Brand
identity, on the other hand, provides a basis for
internal branding strategy, but is also the source of
brand equity for high technology companies.
Consequently, brand identity is the key concept of
this thesis, providing direction, depth, and texture
for the other branding dimensions.
Figure 3. Brand identity, high-tech branding and
internal branding relationships
By studying employee perceptions of brand
identity, it should be possible to assess the strengths
and weaknesses of the current state of employee-
brand relationship and whether there is a need for
better brand identity management.
3. Research process and data collection
The case company is leading macedonian
carrier of electronic communications, which offers
to its customers a wide array of top excellence
telecommunication services and amusing contents
within the scope of the fixed network, broadband
services and integrated solutions, also including TV
over Internet Protocol (IPTV). The Companys
product portfolio includes Internet Protocol based
services, data transfer, sale and lease of equipment
and services for system integration. The company
currently consists of eight different departments.
This thesis bases on deductive research approach,
which involves the development of a theory that is
subjected to a rigorous test. The study is executed
according to a holistic case-study strategy, which
also employs characteristics of survey strategy in
the form of a questionnaire. It is consisted from a 22
items in two main sections (Table 2).
The first section of the questionnaire,
questions from 1 to 12, measures whether the
employees know what their brand stands for, and
the second section, questions from 13 to 22,
measures whether they care. The measurement scale
used in the sections was a five-point Likert scale
reflecting agreement in the 1st section and
importance in the 2nd
section. In the 1st section, the
higher the level of agreement is, the better the
employees know: number 1 to the outcome of
strongly disagree, 2 to disagree, 3 to neither
agree nor disagree, 4 to agree and, finally, 5 to
strongly agree. In the 2nd
section, the higher the
level of importance is, the more the employees care:
number 1 to the outcome of unimportant, 2 to
less important, 3 to neither unimportant nor
important, 4 to important and, finally, 5 to very
important.
The biggest
challenge
R
e
l
a
t
i
o
n
s
h
i
p
Reflection
Personality Physique
Self-image
C
u
l
t
u
r
e
BRAND IDENTITY
Source of
brand
equity
Fondation
for strategy
HIGH-TECH
BRANDING
INTERNAL
BRANDING
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Copyright 2013 by Technical University Sofia, branch Plovdiv, Plovdiv, BULGARIA. ISSN 1310 - 8271
Questions from 1, 2, 3, 4, 13 and 14 reflect
culture, questions 5, 6, 15 and 16 reflect personality,
questions 7, 8, 17 and 18 reflect physique, questions
9, 10, 19 and 20 reflect relationship, questions 11
and 21 reflect reflection, and, finally, questions 12
and 22 reflect self-image. Further, questions 5, 6, 7,
8, 15, 16, 17 and 18 represent issues related to the
company itself, whereas questions 11, 12, 21 and 22
reflect issues related to customers.
In order to reduce the possibility of getting
biased, misleading or wrong research results, it is
necessary to pay attention to two particular
emphases on research design reliability and
validity [8]. Both terms signify trustworthiness;
reliability tests how consistently a measuring
instrument measures whatever concept it is
measuring, whereas validity tests how well an
instrument that is developed measures the particular
concept it is supposed to measure.
A total amount of 574 responses was
received from the employees. The largest groups of
respondents were obviously from sales and service
departments, while finance, IT and marketing
departments were represented with smaller groups
of respondents (Table 1).
Table 1
Respondents according to departments
Department Number of
Respondents %
Sales 224 39.0%
Marketing 14 2.4%
Services 182 31.7%
IT 56 9.8%
Finance 98 17.1%
Total: 574 100.0%
Table 3 presents a summary of the research
results according the chosen level of agreement and
importance for every different question.
From the questions considering the culture
of the brand, there is high level of agreement and
importance, expect for Q2 considering the clear
understanding of the company's vision most of the
responders neither disagree nor agree.
The highest levels of agreement and
importance were noticed on every question
considering the brand personality. The same results
are received on the remaining groups of questions
considering physique, relationship, reflection and
self-image of the brand. Only the responses on Q7
shows that responders generally neither disagree nor
agree with this issue.
Table 2
Questionnaire
Section 1: Please indicate your level of agreement with
each of the following statements
(1 - stongly disagree, 5 - strongly agree)
Agreement
1
I have clear understanding of what the company mission
is
2 I have clear understanding of what the company vision
is
3 I have clear understanding of what the company values
is
4 Mission, vision and values of my company are reflected
in my everyday work
5 I understand how my company wants to be seen by
customers, competitors and media
6 I know what makes my company different from its competitors
7 I know what customer needs my company is fulfilling
with its products and services
8
I think that my company transmits a constant visual
image through its facilities, advertising and communication material
9 I know what I, as an employee, have to do in order to
deliver on my company's product promise
10 I know what I, as an employee, have to do in order to satisfy customers' needs and expectations
11 I have a clear idea of how the customers feel about my
company's products and services
12 I know what my company's customers are like
Section 2: Please indicate your level of importance with
each of the following statements (1 - unimportant, 5 - very
important)
Importance
13
A common, company-wide understanding of the
company mission, vision and values
14 Implementing the company mission, vision and values
in my everyday work
15 Other people's opinion of my company
16 Superiority of my company compared to its competitors
17 The offer of products and services of my company
18 A constant visual implementation of the company
facilities, advertising and communication material
19 Company's expectations of me as an employee
20 Customer's expectations of me as an employee
21 Customer perceptions of and attitudes towards the
company
22 Knowing who customers are
23
Circle your department:
Sales
Marketing Services
IT
Finance
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Table 3
Summary of research results according the level of
agreement and importance
AGREEMENT 1 2 3 4 5
Q1
Culture 0 74 148 222 130
Q2
Culture 0 116 176 120 162
Q3
Culture 0 42 176 180 176
Q4
Culture 0 28 120 236 190
Q5
Personality 0 14 46 152 362
Q6
Personality 0 0 14 124 436
Q7
Physique 112 28 180 162 92
Q8
Physique 0 172 0 116 286
Q9
Relationship 0 0 0 106 468
Q10
Relationship 0 0 0 78 496
Q11
Reflection 0 0 46 74 454
Q12
Self-image 0 0 46 130 398
IMPORTANCE 1 2 3 4 5
Q13
Culture 0 14 96 138 326
Q14
Culture 0 14 64 183 312
Q15
Personality 0 0 28 124 422
Q16
Personality 0 0 60 110 404
Q17
Physique 0 0 60 78 436
Q18
Physique 0 32 14 92 436
Q19
Relationship 0 14 32 92 436
Q20
Relationship 0 0 0 106 468
Q21
Reflection 0 0 14 88 472
Q22
Self-image 0 14 78 74 408
4. Conclusions
The level of brand knowledge and
commitment in the macedonian telecommunication
company was very good, even though some
weaknesses were identified company's vision and
fulfilling customer needs with products and
services.
References
1. Sawhney, M. 2005. Branding in Technology
Markets. Chapter 11 in Kellogg on Branding: The
Marketing Faculty of the Kellogg School of
Management. Eds. Tybout, A., Calkins, T. New
Jersey: Jon Wiley & Sons.
2. Davis, S. 2005. Building a Brand-Driven
Organization. Chapter 12 in Kellogg on Branding:
The Marketing Faculty of the Kellogg School of
Management. Eds. Tybout, A.,