FM and Sm Lab Manual
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Transcript of FM and Sm Lab Manual
PRIST UNIVERSITY PUDUCHERRY CAMPUS
FACULTY OF ENGINEERING &TECHNOLOGY
FLUID MECHANICS AND STRENGTH OF MATERIAL LABORATORY
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 1
PRIST UNIVERSITY, PUDUCHERRY CAMPUS
Faculty of engineering & technology
Department: Mechanical engineering
LABORATORY RECORD
2013
Certified that this is a bonafide record of work done by register no………………..Name:…………………………..Of IInd year / Mechanical in fm and sm laboratory during the year 2013.
Signature of the staff in-charge HOD
Submitted for the practical examination held on……………..
INTERNAL EXAMINER EXTERNAL EXAMINER
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 2
LIST OF EXPERIMENTS OF SM
S.NO DATE NAME OF THE EXPERIMENT PAGENO
SIGN
1.Tension test on a mild steel rod
2. Torsion test on mild steel rod
3.Impact test on metal specimen
4.Hardness test on metals - Brinell and
Rockwell Hardness Number
5.Compression test on helical springs
6.Deflection test on beams
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 3
LIST OF EXPERIMENTS OF FM
S.NO
DATE NAME OF THE EXPERIMENT PAGENO
SIGN
1.Determination of the Coefficient of discharge of given Venturi meter.
2.
Determination of friction factor for a given set of pipes
3.
Conducting experiments and drawing the characteristic curves of centrifugal pump
4.
Conducting experiments and drawing the characteristic curves of reciprocating pump.
5.
Conducting experiments and drawing the characteristic curves of Pelton wheel.
6.
Conducting experiments and drawing the characteristics curves of Francis turbine
COMPLETED / NOT COMPLETED SIGNATURE OF THE STAFF IN-CHARGE
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 4
1.Tension test on a mild steel rod
Aim: To determine the tensile strength of specimen
Specimen and equipments
1. Universal testing machine 2. Specimen
Figure 1.a
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 5
Figure.1b
Theory
The tensile test is most applied one, of all mechanical tests. In this test ends of a test piece are fixed into grips connected to a straining device and to a load measuring device. If the applied load is small enough, the deformation of any solid body is entirely elastic. An elastically deformed solid will return to its original position as soon as load is removed. However, if the load is too large, the material can be deformed permanently. The initial part of the tension curve (fig.8), which is recoverable immediately after unloading, is termed as elastic and rest of the curve, which represents the manner in which solid undergoes plastic deformation is termed plastic. the stress below which the deformation is essentially entirely elastic is known as the yield strength of material. In some materials (like mild steel) the onset of plastic deformation is denoted by a sudden drop in load indicating both an upper and lower yield point. However, some materials do not exhibit a sharp yield point. During plastic deformation, at larger extensions strain hardening cannot compensate for the decrease in section and thus the load passes trough a maximum and then begins to decrease. As this stage the’ Ultimate strength ‘, which is defined as the ratio of the specimen to original cross –sectional area, reaches a maximum value. Further loading will eventually cause ‘neck’ formation and rupture.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 6
Usually a tension test is conducted at room temperature and the tensile load is applied slowly. During this test either round or flat specimens (fig.7) may be used. The round specimens may have smooth, shouldered or threaded ends. The load on the specimen is applied mechanically or hydraulically depending on the type of testing machine.
Stress strain diagram
Procedure
1. Measure the dimensions of a specimen Diameter,Total length of a specimen,Cross sectional area = AoMark gage length (Lo) at three different portions on the specimen, covering effective length of a specimen.(this is required so that necked portion will remain between any two points of gage length on the specimen.)
2. Grip the specimen in the fixed head of a machine. (Portion of the specimen has to be gripped as shown in the fig.7.
3. Fix the extensometer within the gauge length marked on the specimen. Adjust the dial of extensometer at zero.
4. Adjust the dial of a machine to zero, to read load applied.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 7
5. Select suitable increments of loads to be applied so that corresponding elongation can be measured from dial gauge.
6. Keep speed of machine uniform. Record yield point, maximum load point, point of breaking of specimen.
7. Remove the specimen from machine and study the fracture observes type of fracture.
8. Measure dimensions of tested specimen. Fit the broken parts together and measure reduced diameter and final gage length.
Observations
Specimen prepared from M.S bar/CI/Al
1. Diameter ( d )= __________ mm
2. Gage length (lo) _______________mm
3. Original cross sectional area of the specimen (Ao) = _________ mm2
4. Final gage length obtained( Lo)= _____________________mm
5. Final diameter obtained =________________mm
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Observation table 1
Sr. Load applied (N) Area of a Stress Modulus ofNo (p) specimen N/mm2 elasticity (E)
(Ao) N/mm2
Observation table 2.
Sr.Contraction in
Deformation Lateral Linear Poisson
No diameter (dd) in length strain strain ratio(mm) (mm)
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 9
Tabulation:
S.NO LOAD STRESS EXTENSOMETER READINGS STRAIN REMARKSDIVISION MM
Graph: Graph between stress (y-axis) and strain (x-axis). From the graph, for a chosen stress, read the corresponding strain.
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Results
a. Modulus of elasticity
Hook’s law states that stress is always proportional to strain within elastic limit. The ratio of stress and strain is constant, called modulus of elasticity or young’s modulus (E)
E= Stress/strain
b. Yield stress (fy);
The point, at which strain increases without increase in stress, is known as Yield point. Stress measured at yield point is called yield stress.
c. Tensile strength:
Maximum carrying capacity of a material in tension is called tensilestrength
Tensile strength= maximum tensile load/ original cross sectional Area.
d. Percentage elongation:
The extension produced in a gage length, expressed as a percentage of its original value(LO)
% Elongation=[(LO’ – Lo)/Lo] X 100
where Lo’ is final gage length after fracture.
e. Percentage reduction in area:
= [(AoAo’)/Ao ] X100
whereAo’ is final reduced cross sectional area after fracture.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 11
2. Torsion test on a mild steel rod
Aim : To find the modulus of rigidity.
Apparatus required:
1. A torsion testing apparatus, 2. Standard specimen of mild steel or cast iron. 3. Twist meter for measuring angles of twist 4. A steel rule and calipers and micrometer.
Figure.9.
Theory:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 12
A torsion test is quite instrumental in determining the value of rigidity (ratio of shear stress to shear strain) of a metallic specimen. The value of modulus of rigidity can be found out through observations made during the experiment by using the torsionequatio
n:T
=Cq or C
=Tl
I p l I p q
Where T=torqueapplied, Ip= polar moment of inertia, C=modulus of rigidity,= Angle of twist (radians), and l= gauge length.
In the torque equipment refer fig. One end of the specimen is held by a fixed support and the other end to a pulley. The pulley provides the necessary torque to twist the rod by addition of weights (w). The twist meter attached to the rod gives the angle of twist.
Procedure:
1. Prepare the testing machine by fixing the two twist meters at some constant lengths from fixed support.
2. Measure the diameter of the pulley and the diameter of the rod.
3. Add weights in the hanger stepwise to get a notable angle of twist for T1 and T2
4. Using the above formula calculate C
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 13
Tabulation:
LOAD TROPTOMETER READINGS
ANGLE OF TWIST IN DEGREES
TORQUE IN NM
RIGIDITYINITIAL FINA
LDIFFERENCE
Graph:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 14
Graph between twist (y-axis) and torque (x-axis).
Result:
Modulus of rigidity of the shaft was found as
3. Impact test on metal specimen
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 15
Aim :To determine the impact toughness (strain energy
throughizod test and charpy test
Apparatus required:
1. Impact testing machine-charpy type and izod type2. Vernier caliper3. Scale
Theory
In a impact test a specially prepared notched specimen is fractured by a single blow from a heavy hammer and energy required being a measure of resistance to impact.
Impact load is produced by a swinging of an impact weight W (hammer) from a height h. Release of the weight from the height h swings the weight through the arc of a circle, which strikes the specimen to fracture at the notch (fig..
Kinetic energy of the hammer at the time of impact is mv2/2, which is equal to the relative potential energy of the hammer before its release. (mgh),where m is themass of the hammer and v = 2 gh is its tangential velocity at impact, g is
gravitational acceleration (9.806 m/s2) and h is the height through which hammer falls. Impact velocity will be 5.126 m/s or slightly less.Here it is interesting to note that height through which hammer drops determines the velocity and height and mass of a hammer combined determine the energy.
Energy used can be measured from the scale given. The difference between potential energies is the fracture energy. In test machine this value indicated by the pointer on the scale. If the scale is calibrated in energy units, marks on the scale should be drawn keeping in view angle of fall () and angle of rise (. Height h1 and h2 equals,
h1= R (1cos q) and h2= (1cos q).
With the increase or decrease in values, gap between marks on scale showing energy also increase or decrease. This can be seen from the attached scale with any impact machine.
Energy used in fracturing the specimen can be obtained approximately as Wh1Wh2
This energy value called impact toughness or impact value, which will be measured, per unit area at the notch.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 16
Izod introduced Izod test in 1903. Test is as per the IS: 1598Charpy introduced Charpy test in 1909. Test is as per the IS: 1499.
a. Izod test
Specimen and equipment
1. Impact testing machine.(fig.3) 2. Specimen and v notch is shown in the fig.4. Size of the specimen is
10mm X 10mm X 75mm
Mounting of the specimen:
Specimen is clamped to act as vertical cantilever with the notch on tension side. Direction of blow of hammer is shown in fig. (). Direction of blow is shown in fig
Figure. 3.a
Izod Impact testing equipment
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 17
Figure 3.b
Schematic impact testing
Figure 4
Position of specimen for Izod test
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Procedure:
1. Measure the dimensions of a specimen. Also, measure the dimensions of The notch.
2. Raise the hammer and note down initial reading from the dial, which will be energy to be used to fracture the specimen.
3. Place the specimen for test and see that it is placed center with respect to hammer. Check the position of notch.
4. Release the hammer and note the final reading. Difference between the initial and final reading will give the actual energy required to fracture the Specimen.
5. Repeat the test for specimens of other materials. 6. Compute the energy of rupture of each specimen.
TABULATION:
S.NO MATERIAL OF THE SPECIMEN
SIZE OF THE SPECIMEN ENEGY ABSORBED TO BREAK THE SPECIMEN
Observation:
1. material of the given specimen=2. types of notes=3. length of the specimen=4. breadth of the specimen=5. depth of the specimen=6. position of groove from one end=7. depth of the groove=8. width of the groove=9. width of the groove=10. initial charpy scale reading=11. final charpy scale reading=
Result : Strain energy of given specimen is
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 19
b . Charpy test
Specimen and equipment:
1. Impact testing machine. (Fig.6) 2. U notch is cut across the middle of one face as shown in (fig.5).
Figure 5
Specimen for Charpy test
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 20
Figure 6
Charpy impact testing equipment
Mounting of specimen
Specimen is tested as a beam supported at each end (fig.7). Hammer is allowed to hit then specimen at the opposite face behind the notch.
Figure.7
Mounting of specimen
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Procedure :
1. Measure the dimensions of a specimen. Also, measure the dimensions of The notch.
2. Raise the hammer and note down initial reading from the dial, which will be energy to be used to fracture the specimen.
3. Place the specimen for test and see that it is placed center with respect to hammer. Check the position of notch.
4. Release the hammer and note the final reading. Difference between the initial and final reading will give the actual energy required to fracture the Specimen.
5. Repeat the test for specimens of other materials. 6. Compute the energy of rupture of each specimen.
Tabulation:
S.NO MATERIAL OF THE SPECIMEN
SIZE OF THE SPECIMEN
ENEGY ABSORBED TO BREAK THE SPECIMEN
Observation:1. material of the given specimen=2. types of notes=3. length of the specimen=4. breadth of the specimen=5. depth of the specimen=6. position of groove from one end=7. depth of the groove=8. width of the groove=9. width of the groove=10. initial charpy scale reading=11. final charpy scale reading=
Result : Strain energy of given specimen is
4. Hardness test on metals - Brinnell and Rockwell
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 22
Hardness Number
Rockwell Hardness test
Aim: To determine the hardness the Hardness of the
given Specimen using Rockwell hardness test.
Apparatus required:
Rockwell hardness testing machine. Black diamond cone indenter, Hard steel specimen.
Theory:
Rockwell test is developed by the Wilson instrument co U.S.A in 1920.
This test is an indentation test used for smaller specimens and harder materials. The test is subject of IS: 1586.In this test indenter is forced into the surface of a test piece in two operations, measuring the permanent increase in depth of an indentation from the depth increased from the depth reached under a datum load due to an additional load.
Measurement of indentation is made after removing the additional load. Indenter used is the cone having an angle of 120 degrees made of black diamond.
Precautions:
1. Thickness of the specimen should not be less than 8 times the depth of indentation to avoid the deformation to be extended to the opposite surface of a specimen.
2. Indentation should not be made nearer to the edge of a specimen to avoid unnecessary concentration of stresses. In such case distance from the edge to the center of indentation should be greater than 2.5 times diameter of indentation.
3. Rapid rate of applying load should be avoided. Load applied on the ball may rise a little because of its sudden action. Also rapidly applied load will restrict plastic flow of a material, which produces effect on size of indentation.
Procedure:
4. Examine hardness testing machine (fig.1). 5. Place the specimen on platform of a machine. Using the elevating
screw raise the platform and bring the specimen just in contact with the ball. apply an initial load until the small pointer shows red mark.
6. Release the operating valve to apply additional load. Immediately after the additional load applied, bring back operating valve to its position.
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7. Read the position of the pointer on the C scale, which gives the hardness no
8. Repeat the procedure five times on the specimen selecting different points for indentation.
Observation
1. Take average of five values of indentation of each specimen. Obtain the hardness number from the dial of a machine.
2. Compare Brinell and Rockwell hardness tests obtained.
Tabulation:
S.NO
MATERIAL LOAD IN KGF
INTENTER SCALE
TRIAL NUMBER ROCKWELLHARDNESS(HRB)
TRIAL 1 TRIAL 2 TRIAL 3
01 MS
02 BRASS
03 ALUMINIUM
Figure .1
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Result:
Rockwell hardness of given specimen is
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Brinell hardness test.
Aim : To determine the hardness of the given specimen using Brinell hardness test.
Apparatus required:
1. Brinell hardness tester (fig.2)2. Aluminum specimen3. Ball indenter.
Specification of the given m/c
Load range In stages of 500kgf up to 3000kgfMaximum test height 254mmDepth of throat 150mmGross weight 210 kg ( approx)Height 900mmSize of base 495x255mm
Precautions
1. Thickness of the specimen should not be less than 8 times the depth of indentation to avoid the deformation to be extended to the opposite surface of a specimen.
2. Indentation should not be made nearer to the edge of a specimen to avoid unnecessary concentration of stresses. In such case distance from the edge to the center of indentation should be greater than 2.5 times diameter of indentation.
3. Rapid rate of applying load should be avoided. Load applied on the ball may rise a little because of its sudden action. Also rapidly applied load will restrict plastic flow of a material, which produces effect on size of indentation.
4. Surface of the specimen is well polished, free from oxide scale and any foreign material.
Theory
Hardness of a material is generally defined as Resistance to the permanent indentation under static and dynamic load. When a material is required to use under direct static or dynamic loads, only indentation hardness test will be useful to find out resistance to indentation.
In Brinell hardness test, a steel ball of diameter (D) is forced under a load (F) on to a surface of test specimen. Mean diameter (d) of indentation is measured after the removal of the load (F).
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 26
Tabulation:
S.NO
MATERIAL LOAD IN KGF
DIAMETER OF THE
INTENTER IN MM
DIAMETER OF THE INTENTER
BRINELL HARDNESS
NUMBER(BHN)1 2 AVG
01 MS
02 BRASS
03 ALUMINIUM
Observation
1. Take average of five values of indentation of each specimen. Obtain the hardness number from equation (!).
2. Compare Brinell and Rockwell hardness tests obtained.
Procedure
1. Apply the load as per the tabular column shown.
Loads and indenter for brinell hardness test
BALL INDENTOR(D)
LOAD IN KILOGRAMSFERROUS MATERIALS NON-FERROUS MATERIALS
(STEEL AND IRON)30D X D
BRASS10XDXD
ALUMINIUM5XDXD
SOFT BEARING MATERIAL 2.5XDXD
10MM 3000 1000 500 250
5MM 750 250 ------ -----
2.5MM 187.5 ----- ----- -----
Tabular column for various metals
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 27
2. Apply the load for a minimum of 15 seconds to 30 seconds. [if ferrous metals are to be tested time applied will be 15 seconds and for softer metal 30 seconds]3. Remove the load and measure the diameter of indentation nearest to 0.02 mm using microscope (projected image)4. Calculate Brinell hardness number (HB). As per IS: 1500.5. Brinell hardness number
2 F(1)
p D [D - D 2 - d 2 ]where D is the diameter of ball indenter and d is the diameter of indentation. Hardness numbers normally obtained for different materials are given below (under 3000 kg and 10 mm diameter ball used)
Ordinary steels medium 100 to 500 carbon 130 to 160
Structural steel 800 to 900
Very hard steel
Note: Brinell test is not recommended for then materials having HB over 630.It is necessary to mention ball size and load with the hardness test when standard size of ball and load are not used. Because indentation done by different size of ball and load on different materials are not geometrically similar. Ball also unergoes deformation when load is applied. Material response to the load is not same all the time.6.Brinell hardness numbers can be obtained from tables 1 to 5 given in IS: 1500, knowing diameter of indentation, diameter of the ball and load applied.Figure 2
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Result :
The Brinell hardness number of the specimen is
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 29
5. Compression test on helical springs
Aim: To determine the modulus of rigidity and stiffness of the given compression spring specimen.
Apparatus and specimen required:
1. Spring test machine 2. Compression spring specimen
3. Vernier Caliper
Procedure:
1. Measure the outer diameter (D) and diameter of the spring coil (D) for the given compression spring.
2. Count the number of turns (i.e.,) coil (n) in the given compression specimen. 3. Place the compress spring at the centre of the bottom beam of the spring testing machine. 4. Rise the bottom beam by rotating right side wheel till the spring top touches the middle
cross beam. 5. Note down the initial reading form the scale in the machine. 6. Apply a load of 25kg and note down the scale reading. Increase the load at the rate of
25kg up to a maximum of 100kg and note down the corresponding scale readings. 7. Find the actual deflection of the spring for each load by detecting the initial scale reading
from the corresponding scale reading. 8. Calculate the modulus of rigidity for each load applied by using the following formula Modulus of rigidity, N=64Pr3n / D4δWhere,P=load in NewtonR=mean radius of the spring in mm D=diameter of the spring coil in mm
δ =deflection of the spring in mm
D=outer diameter of the spring in mm
9. Deter mine the stiffness of each load applies by using the following formula: stiffness,10. Find the value of modulus of rigidity and spring constant of the given spring by taking
average values.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 30
Observation:
1. Material of the spring specimen=spring steel2. Outer diameter of the spring, D =3. Diameter of the spring coil, d=4. Number of coils /turns, n =5. Initial scale reading=
TABULATION:
S.NO APPLIED LOAD IN SCALE READING IN ACTUAL DEFLECTION
IN MM
MODULUS OF RIGIDITY IN
N/MM2
STIFFNESS
IN N/MM2
KG N CM MM
AVERAGE
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MODEL GRAPH:
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Result:
The modulus of rigidity of the given spring =……………. The stiffness of the given springs=………………………..
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6.DEFLECTION TEST VERIFICATION OF MAXWELL’S
RECIPROCAL THEOREM
Aim:
To verify Maxwell’s reciprocal theorem by conducting deflection test for the given specimen.
Maxwells reciprocal theorem:
In any beam, the deflection at a point A due to the load at a point B is equal to the deflection at the point B due to the same load at the point A and vice versa.
Apparatus and Specimen required:1. Bending table or Bench type apparatus2. Beam specimen3. Dial gauge with stand4. Set of weights with load hanger5. Vernier caliper and scale.
Procedure:1. Measure the length (L), breadth (b) and depth (d) of the given beam specimen.
2. Place the beam specimen over two knife edge supports in the bending table apparatus and measure centre to centre distance between the supports. The distance is known as span of the beam (l).
3. Mark two points A and Bin the beam at a distance of l/3 and 2l/3, respectively from left support.
4. for first case (case I), place the load hanger at a point A and dial gauge at point B. Now adjust the dial gauge reading at zero.
5. Apply kg load on the load hanger and note down the dial gauge reading. Increase the load at the rate of kg and note down the corresponding dial gauge reading. After the maximum loading, remove the load at the rate pf kg and note down the corresponding dial gauge readings.
6. For the next case (case II), change the dial gauge to point Aand the load hanger to point B and adjust the dial gauge reading to zero. Repeat the same procedure in step.4.
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7. Find the average value of loading and unloading dial gauge readings for both the cases.8. Find the actual deflection by multiplying the average value with least count of the dial gauge.
Discussion:When a load of -----------N applied at point A gives a deflection of ---------------mm at B. When the same load applied B gives a deflection of ----------------mm t A. Both these deflections are --------------------.
Observation:1. Material of specimen =2. Length of the specimen, (L) = mm3. Span of the specimen, l = mm4. Breadth of the specimen, b = mm5. Depth of the specimen. D = mm6. Least count (LC) of the dial gauge = mm
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CASE I CASE II
LOAD AT A
IN
DEFLECTION AT B DEFLECTION AT A
Kg N DIAL GAUGE READING IN DIVISION Actual deflectio
n in mm (L.C x Avg.)
DIAL GAUGE READING IN DIVISION Actual deflection
in mm (L.C x Avg.)
LOADING
UNLOADING
AVERAGE LOADING UNLOADING
AVERAGE
MODEL GRAPH:
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Result:
Since the deflection are ------ for both the cases, which proves reciprocal theorem.
1.Determination of the Coefficient of discharge of given Venturi meter
AIM:
To Determination of the Coefficient of discharge of given Venturi meter
Apparatus Required:
1. Venturi meter.2. Stop watch.3. Sump tank.4. Measuring tank5. Pump set. 6. Pipe lines.
DESCRIPTION OF THE MAIN PARTS
SUMPTANK:
The suitable capacity sump tank made by mild steel to store sufficient water circulates independently through the unit. Inside of the tank is lined by FRP. It is having a drain arrangement to drain the water wherever the unit is in idle. The sump tank is placed on a sturdy iron stand.
MEASURING TANK:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 38
The suitable capacity measuring tank made of mild steel with FRP lining and drain valve, piezometer, glass tube, scale arrangement.
PUMP SET:
½ HP, single phase mono block pump set of size 1”x 1” suitable to pump the water throughout the unit for independent circulation.
PIPE LINES:
Two G.I. pipe lines of size 25mm and 20mm with fittings and control valves and pressure tapings, PVC hoses to connect manometer.
MANOMETER:
A 1 m differential u-tube manometer with mercury provided to measure the differential head from venturi meter . A common unit having separate valves for taking reading either by 25mm or 20mm pipe line.
SPECIFICATION FOR VENTURI METER:
Venturi meter size : 25mm. & 20mm
Throat size : 14.79mm & 11.8mm
Diameter Ratio : 0.5916 & 0.59
Area Ratio : 0.35 &
PROCEDURE
Before starting close the gate vales and manometer cocks.
Switch on the power supply and gradually open the gate value of the venture meter pipe line and manometer cocks. Fill the water in the manometer glass to remove the air.
Note down the manometer readings h1 and h2. Take the differential head (h=h1—h2)
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Close the drain value of the measuring tank. Take the time taken for 10 cm raise of meter in the piezo meter by means of stop watch.
Adjust the 25 mm gate value for next reading the same procedure repeated for 20mm value also.
By using manometer reading we find out the theoretical discharge and by measuring tank find out the actual discharge.
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Pipe Diameter = 25mm pipe dia = 20 mm
Pipe Area = a1 = πd1
4Pipe Area = a2 =
πd2
4
Throat dia d1 = 14.79 mm Throat dia = 11.8 mm
Orifice area a1 = Orifice area a2 =
TABULAR FORM
SNO Manometer readings ‘mm’ of Hg
Theoretical discharge m3 / sec. Qt
Time for 10 cm raise of water sec
Actual dischargem3/s. Qa
Cd= Qa Qt
H1 H2 H
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DIAGRAM OF VENTURIMETER:
MODEL GRAPH:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 42
FORMULA:
1. Theoretical discharge Qt = a 1 a 2√2 gH√¿¿¿ m3/s
H= (h1-h2)×10.3
760
2. Actual discharge Qa= AHT m3/s
A=area of measuring tank
H= raise of water level (10 cm)
T = Time taken for ‘H’ raise of water.
3. Co-efficient of discharge Cd= Qa
Q t
RESULT:
The co-efficient of discharge through venturi meter is………. (No unit)
2. Determination of friction factor for a given set of pipes.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 43
AIM:
To determine the friction factor for a given set of pipes. APPARATUS REQUIRED:
1. Closed circuit pipe friction apparatus.2. Stop watch3. Sump tank 4. Measuring tank 5. Pump set6. Pipe lines 7. Manometer
DESCRIPTION OF THE MAIN PARTS
SUMP TANK:
The suitable capacity sump tank made by mild steel to store sufficient water circulates independently through the unit. Inside of the tank is lined by FRP. It is having a drain arrangement to drain the water wherever the unit is in idle. The sump tank is placed on a sturdy iron stand.
MEASURING TANK:
The suitable capacity measuring tank made by mild steel to measure the quality of water pump by the submersible pump at various delivery heads. It having the arrangement to provide the gauge glass and scale arrangement. It also has a arrangement to drain the water by a poly propylene valve with an elbow to allow the water to the sump tank. The whole arrangement is placed on the sump tank.
PUMP SET:
½ HP, single phase mono block pump set of size 1”x 1” suitable to pump th water throughout the unit for independent circulation.
PIPE LINES:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 44
Two G.I. pipe lines of size 25mm and 20mm with fittings and control valves and pressure tapings.
MANOMETER :
A ½ m differential manometer with mercury provided to measure the differential head.
PROCEDURE:
Before starting close the gate vales and manometer cocks.Switch on the power supply and gradually open the 25mm gate value fully.
Open the manometer cocks and remove the air from the glass tube by filling water.
Move down the manometer readings h1 and h2. Take the differential head (h=h1—h2)
Close the drain value of the measuring tank. Take the time taken for 10 cm raise of meter in the piezometer by means of stop watch.
Adjust the 25 mm gate value for next reading the same procedure repeated for 20mm value also.
FORMULA:
(A) hf = 4 fl v2
2gd
Where hf = manometer difference in (m) of water f = friction factor l = length of the pipe (distance between two pressure
Tapings in ‘m’). v = Velocity of flow (m/s) g = Acceleration due to gravity (9.81 m/s2) d = Diameter of the pipe (m)
Manometer head h= h1-h2 m.
in “mm” of Hg.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 45
Manometer head in “m” of water
h × 10.3760 ‘m’
Where ‘h’ in mm of Hg.
Actual discharge of water = Q = AhT m3/s
A = Area of measuring tank. m2 (0.4 × 0.3) h = Raise of water level, 10cm (0.1 m) T = Time for ‘h’raise of water In Seconds.
Area of the pipe(a) = πd2/4 m2
d = diameter of the pipe in “m”
Velocity v= Q/a m/s
Q= discharge a= area of pipe TABULAR COLOUMN
Left limb reading, h1 : mRight limb reading, h2 : mLoss of head, hf : ( h1 – h2) x 13.6 m of waterDiameter of pipe, d : mArea of the pipe, a : ( π/4)d2
Rise of water level in the collecting tank, h : mTime taken for ‘h’ m of water level rise, t : secDischarge of water, Q : Ah/t m3/secVelocity of water, V : Q/a m/sArea of measuring Tank : 0.4 × 0.3 Velocity head hf : v2/2g m F : 2gdh f /LV2
Tabulation:-
Differential manometer Loss of Time for Discharge of Velocity of Velocity head
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 46
Reading in mm of Hg head H
10 cm rise of water T
water
Q
water
V h f
h1 h2 Difference in level (x)
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 47
RESULT:
Friction factor for the given pipe
1. Analytical method……………..2. Graphical method……………..
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 48
3.Conducting experiments and drawing the characteristic curves of centrifugal pump
AIM:
Conducting experiments and drawing the characteristic curves of centrifugal pump
APPARATUS REQUIRED :
1. Closed circuit Centrifugal pump test rig.2. Stop watch.3. Sump tank 4. Measuring tank 5. Centrifugal pump 6. Electric motor 7. Panel board.8. Pipe fitting.
DESCRIPTION OF THE MAIN PARTS:
SUMP TANK:
The suitable capacity sump tank made by mild steel to store sufficient water circulates independently through the unit. Inside of the tank is lined by FRP. It is having a drain arrangement to drain the water whenever the unit is in idle. The sump tank is placed on a sturdy iron stand.
MEASURING TANK:
The suitable capacity of measuring tank made by mild steel to measure at the various delivery heads. It having the arrangement to provide the gauge glass and scale arrangement. The measuring tank placed on a study iron stand.
CENTRIFUGAL PUMP:
A pump of size 25 × 25 mm to discharge about 100 LPM at 5m head, pipeline with gun metal foot valve & gate valve.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 49
MOTOR:
An induction motor of 1HP capacity with stepped pulley for speed variation.
PIPE FITTING:
1” delivery pipe consist of pipe fittings, pressure gauge with cocks and a control valve. 1” suction pipe consist of suction pipe and fittings, vaccum guage with cocks and PVC strainer foot valve. All fittings connected with the centrifugal pump.
PANEL BOARD ARRANGMENT:
Consist of a single phase double pole on/off switch to start or stop the motor. An energy meter provided to measure the input power to the motor by number of thickening of light which is provided with the energy meter.
PROCEDURE:
Before starting the pump check all the joints are tight and leak proof. Fully open the gate valve of the delivery side and close the pressure and
vacuum gauge cocks. Now start the pump and open the gauge cocks. Slightly close the delivery valve and create some reading on the pressure
gauge. Now close the delivery valve of the measuring tank, the water level
increases in the gauge glass. Now start the stop watch, take the time taken for 10 cm raise water level.
Time taken for 5 flickering of light on the energy meter also noted by the stop watch.
Note the readings on pressure and vacuum gauge. The whole procedure is repeated for different delivery heads (pressure gauge
readings) for 5 or 6 readings. Do the calculation and find out the performance of the centrifugal pump. Graph also is plotted for self readings.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 50
ENERGY METER CONSTANT = 3200 lpm/ Kw.hr.
MEASURING AREA OF MEASURING TANK =0.6 X 0.4
DISTANCE BETWEEN THE TWO GAUGES (X) = 0.5 m
SL.NO
PERSSURE GUAGE READING Kg/cm2
VACCUM GAUGE READING ‘mm’ OF Hg
TOTAL HEAD ‘m’
TIME FOR 10 cm raise of oil sec.
Discharge m3/sec.
Time for 5 flicking of light sec.
Input power Kw Output power Kw
Efficiency %
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 51
FORMULA:
1. Total Head H =
( Pr . gauge Reading X 10 )+(Vaccum gauge Reading X 10.3760 )+ Datum Head(m)
2. Discharge Q = A X h
Tm3/sec
A = Area of measuring tank m2 (0.6 × 0.4 ) h = Raise of water level (10cm) T = Time for ‘h’raise of water S.
3. Output power = γ Q H Kw Where (γ = 9.81)
4. Input power = Xt
X3600EMC
X 0.8 k . w
x = number of illuminated of light. T = time for ‘x’ illumination EMC = Energy meter Constant 3200 lmp/Kw hr. 0.8 = Efficiency of motor (80% )
5. Efficiency of pump = OUTPUT POWER
INPUT POWERX 100
MAINTENANCE:
As these units are built very sturdily, they do not require any routine or regular maintenance. However, we recommend the following to be done about once in a year to increase the life of the elements.
Lubricate all the working parts where provision for lubrication is made. Grease cups are provided for lubricating ball bearings.
Never run the pump without water in it, as this would cause damage to stuffing box, bush bearing etc.
Never try to throttle the suction side of the pump to control discharge as it would seriously affect the performance of the pump.
Drain the water from the sump when the unit is in idle.
Model graph:
1. Actual discharge vs. total head2. Actual discharge vs. efficiency3. Actual discharge vs. input power4. Actual discharge vs. output power
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 53
View of centrifugal pump:
RESULT:
Thus the performance characteristic of centrifugal pump was studied and the maximum efficiency was found to be………. %
4. Conducting experiments and drawing the characteristic curves of reciprocating pump
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 54
AIM:
To Conduct experiments and draw the characteristic curves of reciprocating pump
APPARATUS REQUIRED :
1. Closed circuit reciprocating pump test rig.2. Stop watch.3. Sump tank. 4. Measuring tank. 5. Reciprocating pump. 6. Electric motor.7. Panel board.8. Pipe fitting.
DESCRIPTION OF THE MAIN PARTS
SUMP TANK:
The suitable capacity sump tank made by mild steel to store sufficient water circulates independently through the unit. Inside of the tank is lined by FRP. It is having a drain arrangement to drain the water whenever the unit is in idle. The sump tank is placed on a sturdy iron stand.
MEASURING TANK:
The suitable capacity measuring tank made by mild steel to measure at the various delivery heads. It having the arrangement to provide the gauge glass and scale arrangement. The measuring tank placed on a study iron stand.
RECIPROCATING PUMP:
A pump of size 25 ×20 mm to discharge about 1730 LPH at 40 meters head, pipeline with gun metal foot valve & gate valve. (BORE: 40mm, STROKE: 45mm, SPEED: 250 rpm)
MOTOR:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 55
An induction motor of 1 HP capacity, A.C. with stepped pulley for multi speed variation.
PIPE FITTING:
3/4” delivery pipe consist of pipe fittings, pressure gauge with cocks and a control valve. 1” suction pipe consist of suction pipe and fittings, vaccum gauge with cocks and PVC strainer foot valve. All fittings connected with the reciprocating pump.
PANEL BOARD ARRANGMENT:Consist of a single phase double pole on/off switch to start or stop the motor.
An energy meter provided to measure the input power to the motor by number of thickening of light which is provided with the energy meter.
PROCEDURE
Before starting the pump check all the joints are tight and leak proof. Fully open the gate valve of the delivery side and close the pressure and
vacuum gauge cocks. Now start the pump and open the gauge cocks. Slightly close the delivery valve and create some reading on the pressure
gauge. Now close the delivery valve of the measuring tank, the water level
increases in the gauge glass. Now start the stop watch, take the time taken for 10 cm raise water level.
Time taken for 5 flickering of light on the energy meter also noted by the stop watch.
Note the readings on pressure and vaccum gauge. The whole procedure is repeated for different delivery heads (pressure gauge
readings) for 5 or 6 readings. Do the calculation and find out the performance of the centrifugal pump. Graph also is plotted for self readings.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 56
ENERGY METER CONSTANT = 3200 lpm/ Kw.hr.
MEASURING AREA OF MEASURING TANK =0.3 X 0.3
DISTANCE BETWEEN THE TWO GAUGES (m) = 0.3 m
SL.NO PERSSURE GUAGE READING Kg/cm2
VACCUM GAUGE READING ‘mm’ OF Hg
TOTAL HEAD ‘m’
TIME FOR 10 cm raise of water sec.
Discharge m3/sec.
Time for 5 flicking of light sec.
Input power Kw
Output power Kw
Efficiency %
NOTE: the pressure should not exceed 3
bar
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (FM-SM LAB MANUAL) Page 57
FORMULA:
6. Total Head H =
( Pr . gauge Reading X 10 )+(Vaccum gauge Reading X 10.3760 )+ Datum Head(m)
7. Discharge Q = A X h
Tm3/sec
A = Area of measuring tank m2 h = Raise of water level (10cm) T = Time for ‘h’raise of water S.
8. Output power = γ Q H Kw Where (γ = 9.81)
9. Input power = Xt
X3600EMC
X 0.8 k . w
x = number of illuminated of light. T = time for ‘x’ illumination EMC = Energy meter Constant 3200 lmp/Kw hr. 0.8 = Efficiency of motor (80% )
10.Efficiency of pump = OUTPUT POWER
INPUT POWERX 100
Model graph:
1. Actual discharge vs. total head2. Actual discharge vs. efficiency3. Actual discharge vs. input power4. Actual discharge vs. output power
View of reciprocating pump:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 59
RESULT:
The performance characteristics of the reciprocating pump is studied and the efficiency is calculated…………..%
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 60
5. Conducting experiments and drawing the characteristic curves of Pelton wheel
AIM:
Conducting experiments and drawing the characteristic curves of Pelton wheel
APPARATUS REQUIRED:
1. Pelton turbine2. A supply pump set to supply water to above pelton turbine3. Flow measuring unit consisting of a venturimeter and a manometer4. Piping system
GENERAL DESCRIPTION:
The unit is essentially consists of casing, with a large circular transparent window kept at the visual inspection of the impact of the jet on the buckets, a rotor assembly of shaft, runner and brake drum, all mounted on a suitable M.S. frame work, a rope brake arrangement is provided to load the turbine. The input to the turbine can be controlled by adjusting the spear position by means of a hand wheel fitted with indicator arrangement. The water inlet pressure is measured by a pressure gauge and RPM tachometer for measurement of speed.
CONSTRUCTIONAL SPECIFICATION:
CASING : is of closed grained cast iron.
RUNNER : is of gunmetal, designed for efficiency operation
Accurately machined and smoothly finished.
SHAFT : is made of EN-8 accurately machined and providedwith a gunmetal sleeve.
NOZZLE : is of gunmetal designed for smooth flow.
SPEAR : is of steel designed for efficient operation.
INLET BEND : of cast iron.
BRAKE : consists of a machined and polished cast iron , , brake drum cooling water pipe standard cast iron dead weight’s, discharge pipe, internal water scoop,
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 61
spring balance, rope brake etc, arranged for loading the turbine.
TECHNICAL SPECIFICATION:
PELTON TURBINE
1. Rated supply head : 45 m2. Discharge : 400 lpm3. Normal speed : 1000 rpm4. Power supply : 1 HP5. Jet diameter : 20 mm6. Brake drum diameter : 200 mm7. Brake rope diameter : 15 mm
SUPPLY PUMPSET
1. Rated head : 53 meters2. Discharge : 440 lpm3. Normal sped : 2880 rpm4. Power required : 5 HP5. Size of pump : 65mm x 50mm6. Type : Centrifugal medium speed, single suction
volute.
FLOW MEASUREMENT UNIT
1. Size of Venturi meter : 50 mm2. Venturi meter area ratio : 0.35 mm3. Throat diameter for Venturi meter : 29.58 mm4. Inlet cone angle for Venturi meter : 20° (21°)5. Diverging cone angle : 10° (14°)6. Manometer : Double column differential
manometer
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 62
STARTING UP
Make sure before starting that the pipelines are free from foreign matter. Also note whether all the joints are water tight and leak proof. The pump starts with closed gate valve. The spear in the turbine inlet should also be in the closed position while starting the pump. See that all the ball bearing and bush bearing in the units are properly lubricated. Then slowly open the gate valve situated above the turbine and open the cock fitted to the pressure gauge and se that the pump develops the rated head. If the pump develops the required head, slowly open the turbine spear by rotating the hand wheel until the turbine attains the normal rated speed.
Load the turbine slowly and take readings. To load the turbine standard dead weights are provided with figures stamped on them to indicate their weights. Open the water inlet valve and allow some cooling water through the brake drum when the turbine runs under load, so that heat generated by the brake drum is carried away by the cooling water. Do not suddenly load the turbine. Load the turbine gradually and at the same time open the spear to run the turbine at the normal speed.
TO SHUT DOWN
Before switching off the supply pump set, first remove all the dead weights on the hanger. Close the cooling inlet water gate valve; slowly close the guide vanes to its full closed position. Then close the gate valve gradually. Manometer cocks and Venturi meter cocks should also be closed, in order to isolate the manometer. Then switch off the supply pump set. Never switch off the supply pump set when the turbine is working under load. Should the electric line trips off when the turbine is working first unload turbine, close all the valves and cocks. Start the electric motor again, when the line gets power and then operate the turbine by opening the valves in the order said above.
TESTING:
Water turbines are tested in the hydraulic laboratory to demonstrate how tests on small water turbine are carried out, to study their construction and to give the students a clear knowledge about the different type of turbines and their characteristics.
Turbines shall be first tested at constant net supply head (at the rated value of 45m) by varying the load, Speed and guide vane settings. However the net supply head on the turbine may be reduced and the turbines tested in which case the
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 63
power developed by the turbine and the best efficiency speed will also be reduced. Through the turbines can also be tested at higher head at the same time maintaining higher rate flow.
The output power from the turbine is calculated from the readings taken on the brake and the speed of the shaft. The input power supplied to the turbine is calculated from the net supply head on the turbine and discharge through the turbine. Efficiency of the turbine being the ratio between the output and input can be determined from these two readings.
The discharge is measured by the Venturi meter of 50mm and with the manometer fitted with the calibrated scale. Supply head is measured with the help of the pressure gauge. (Any calibration error of the gauges should also be taken into account). The speed of the turbine is measured with the digital tachometer.
After starting and running the turbine at normal speed for some time, load the turbine and take readings. Note the following:
1. Net supply head (pressure & vacuum gauge readings plus height of pressure gauge over vacuum gauge).
2. Discharge (manometer readings)3. Turbine shaft speed.4. Brake weight (dead weight plus hanger and rope weight)5. Spring balance readings.
For any particular setting of the setting of the guide vanes first run the turbine at light load and then gradually load it, by adding dead weights on the hanger. The net supply head on the turbine shall be maintained constant at the rated value, and this can be adjusting the gate valve fitted just above the turbine.
MAINTENANCE
As these units are built very sturdily, they do not require any routine or regular maintenance. However, we recommend the following to be done about once in a year to increase the life of the elements.
Lubricate all the working parts where provision for lubrication is made. Grease cups are provided for lubricating ball bearings.
Never run the pump without water in it, as this would cause damage to stuffing box, bush bearing etc.
Never try to throttle the suction side of the pump to control discharge as it would seriously affect the performance of the pump.
Drain the water from the sump when the unit is in idle.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 64
CALCULATIONS:
1. Input power = γ Q H Kw γ = 9.81
Q = discharge in m³/s.H = total head in ‘m’
2. Discharge Q = Cd a1a 2√2 gH√¿¿¿
a1 = π d1
2
4 where d1 = 50mm
a2 = π d2
2
4where d2 = 29.58 mm
g = Acceleration due to gravity (9.81 m/s2 )H = manometer difference in ‘m’ of water
H = h1−h2
1000 X (13.6-1) m of water
Output power:
= 2 πNW Re X 9.81
60,000 Kw
N = Turbine speed in RPM.W = (W1-W2) +1 Kg.
Efficiency = Output powerInput power X 100 %
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 65
I MECH PELTON TURBINE – TESTING:
Head = Runaway speed =
Discharge = Spear opening =
Sl.n
o
Head (H)
(in meters)
Speed (N) RPM
Manometer reading (in mm)
Dis
char
ge
(Q)
(in
cu
m/s
)
Load (in kg)
Net
wei
ght
(W)
(in
Kg)
(W2
–W1)
+1
Inpu
t pow
er
in k
w
Out
put
pow
er in
kw
Eff
icie
ncy
H1 H2 h= H1-H2 W2 W1
1
2
3
4
5
6
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 66
View of pelton wheel:
Model graph:
RESULT:
The performance characteristic of the pelton wheel is studied and the efficiency is calculated…………..%
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 68
6.Conducting experiments and drawing the characteristics curves of Francis turbine
AIM: To conduct experiments and draw the characteristics curves of Francis turbineAPPARATUS REQUIRED:
5. Pelton turbine6. A supply pump set to supply water to above pelton turbine7. Flow measuring unit consisting of a venturimeter and a manometer
4. Piping systemGENDRAL DESCRIPTION :
The Francis Turbine consists of a spiral casing and rotor assembly with runner, shaft and brake drum, all mounted on a suitable fabricated M.S. sump. A straight conical draft tube is provided to know the kinetic energy. A transparent hollow Perspex cylinder is provided in between the draught bend and the casing for the purpose of observation of flow at exit of runner. A rope brake arrangement is provided to load the turbine. The output of the turbine can be controlled by adjusting the guide vanes which the handle wheel and a suitable link mechanism is provided. The net supply head on the turbine is measured by a pressure and vacuum gauge.
CONTRUCTIONAL SPECIFICATION:
Spiral casing : is of closed grained cast iron.
Runner : is of gunmetal, designed for efficiency operation
Accurately machined and smoothly finished.
Guide vane : consists of gunmetal guide vanes, operated by a handwheel through a mechanism. External dummy guide vanes areprovided to indicate the position of the actual guide vanes working inside the turbine.
Shaft : is made of EN-8 accurately machined and provided with a gunmetal sleeve.
Brake
Arrangement : consists of a machined and polished cast iron brake drum, cooling water pipe, standard cast iron dead weight’s, discharge pipe, internal water scoop, spring balance, rope brake etc, arranged for loading the turbine.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 69
TECHNICAL SPECIFICATION:
Francis turbine (reaction turbine)
8. Rated supply head : 10.0 m
9. Discharge : 800 lpm
10.Normal speed : 1000 rpm
11.Brake Power : 1 HP
12.Runaway speed : 1700 rpm
13.No. of guide vanes : 8 no’s
14.Brake drum diameter : 200 mm
15.Brake rope diameter : 15 mm
SUPPLY PUMPSET:
7. Rated head : 15 meters
8. Discharge : 1000 lpm
9. Normal sped : 2880 rpm
10.Power required : 5 HP
11.Size of pump : 75mm x 65mm
6. Type : Centrifugal medium speed, single suction volute. FLOWMEASUREMENT UNIT:
7. Size of Venturi meter : 65 mm
8. Venturi meter area ratio : 0.35 mm
9. Throat diameter for Venturi meter : 38.45 mm
10.Inlet cone angle for Venturi meter : 20°(21°)
11.Diverging cone angle : 10°(14°)
STARTING UP
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 70
Make sure before starting that the pipelines are free from foreign matter. Also note whether all the joints are water tight and leak proof. Prime the pump and start it with closed gate valve. The guide vanes in the turbine should also be in the closed position while starting the pump. See that all the ball bearing and bush bearing in the units are properly lubricated. Then slowly open the gate valve situated above the turbine and open the cock fitted to the pressure gauge and se that the pump develops the rated head. If the pump develops the required head, slowly open the turbine guide vanes by rotating the hand wheel (which operates the guide vane through suitable link mechanism until the turbine attains the normal rated speed.
In addition to this on pump side, note the operation of the stuffing box (the stuffing box should show on occasional drip of water. If the gland is over tightened, the leakage stops but the packing’s will heat up, burn and damage the shaft).
If the operation of the above parts is normal, load the turbine slowly and take readings. To load the turbine standard dead weights are provided with figures stamped on them to indicate their weights. Open the water inlet valve and allow some cooling water through the brake drum when the turbine runs under load, so that heat generated by the brake drum is carried away by the cooling water. Do not suddenly load the turbine. Load the turbine gradually and at the same time open the guide vanes to run the turbine at the normal speed.
TO SHUT DOWN:
Before switching off the supply pump set, first remove all the dead weights on the hanger. Close the cooling inlet water gate valve; slowly close the guide vanes to its full closed position. Then close the gate valve just above the turbine. Manometer cocks and Venturi meter cocks should also be
closed, in order to isolate the manometer. Then switch off the supply pump set. Never switch off the supply pump set when the turbine is working under load.
Should the electric line trips off when the turbine is working first unload turbine, close all the valves and cocks. Start the electric motor again, when the line gets power and then operate the turbine by opening the valves in the order
said above.
TESTING:
Water turbines are tested in the hydraulic laboratory to demonstrate how tests on small water turbine are carried out, to study their construction and to give the students a clear knowledge about the different type of turbines and their characteristics.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 71
Turbines shall be first tested at constant net supply head (at the rated value of 10m) by varying the load, Speed and guide vane settings. However the net supply head on the turbine may be reduced and the turbines tested in which case the power developed by the turbine and the best efficiency speed will also be reduced. Through the turbines can also be tested at higher head at the same time maintaining higher rate flow.
The output power from the turbine is calculated from the readings taken on the brake and the speed of the shaft. The input power supplied to the turbine is calculated from the net supply head on the turbine and discharge through the turbine. Efficiency of the turbine being the ratio between the output and input can be determined from these two readings.
The discharge is measured by the Venturi meter of 65mm and with the manometer fitted with the calibrated scale. Supply head is measured with the help of the pressure gauge. ( any calibration error of the gauges, should also be taken into account). The speed of the turbine is measured with the digital RPM indicator.
It is suggested that the turbine shall be tested at normal speed, 3 speeds below normal speed, and 3 speeds above normal speed covering a range of ± 50% of the normal speed for each setting of the guide vanes. If eight such guide vane positions are used about 70 observations can be made and these readings given a good range for drawing the characteristics of the turbine. The runaway speed (the speed of the turbine at no load and at rated condition of supply head) and pull our torque (the maximum torque at stalled speed) may also be observed. After starting and running the turbine at normal speed for some time, load the turbine and take readings. Note the following:
6. Net supply head (pressure & vacuum gauge readings plus height of pressure gauge over vacuum gauge).
7. Discharge (manometer readings)
8. Turbine shaft speed.
9. Brake weight (dead weight plus hanger and rope weight)
10.Spring balance readings.
For any particular setting of the setting of the guide vanes first run the turbine at light load and then gradually load it, by adding dead weights on the hanger. The net supply head on the turbine shall be maintained constant at the rated value, and this can be adjusting the gate valve fitted just above the turbine.
MAINTENANCE
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 72
As these units are built very sturdily, they do not require any routine or regular maintenance. However, we recommend the following to be done about once in a year to increase the life of the elements.
Lubricate all the working parts where provision for lubrication is made. Grease cups are provided for lubricating ball bearings.
Never run the pump without water in it, as this would cause damage to stuffing box, bush bearing etc.
Never try to throttle the suction side of the pump to control discharge as it would seriously affect the performance of the pump.
Drain the water from the sump when the unit is in idle.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 73
I MECH FRANCIS TURBINE – TESTING:
Head = Runaway speed =
Discharge = Guide vane opening =
Sl.n
o
Head (H)
(in meters)
Speed (N) RPM
Manometer reading (in mm)
Dis
char
ge
(Q)
(in
LP
M) Load (in
kg)
Net
wei
ght
(W)
(in
Kg)
(W2
–W1)
Inpu
t pow
er
Out
put
pow
er
Eff
icie
ncy
H1 H2 h= H1-H2 W2 W1
1
2
3
4
5
6
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 74
CALCULATIONS:
For reading no:-
3. Input power = γ Q H Kw
γ = 9.81Q = discharge in m³/s.H = total head in ‘m’
4. Discharge Q =
a1 = where d1 = 65mm
a2 = where d2 = 38.45 mm g = Acceleration due to gravity (9.81 m/s2 )
H = manometer difference in ‘m’ of water
H = X (13.6-1) m of water
Output power:
= Kw N = Turbine speed in RPM.W = (W1-W2)+1.5 Kg.
Efficiency = X 100 %
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 75
View of francis turbine:
Model graph:
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 76
Result:
Thus the experiment has been conducted and the characteristics curves of Francis turbine are drawn.
PRIST UNIVERSITY-PUDUCHERRY CAMPUS (SM-FM LAB MANUAL) Page 77