Phenomenon+ +Intro+ +PKB

8/3/2019 Phenomenon+ +Intro+ +PKB

1/96

Transport Phenomenon

Project Review

Dr. PK Banerjee


2/96

Role of a Process Engineer

Develop

Design

Engineer equipment & Process

Choose right raw materials

Operate- Efficiently- Safely

- Economically

Delight customer


3/96

What is a Process?

A process is a set of many steps or unit operations

An unit operation is based on a common scientific principle andcould be utilised in varied applications.

examples : size reduction, screening, gravity separation,

transportation, Distillation, leaching, distillation, evaporation,

drying etc.


4/96

Dimensions and Units

Review

Dimension: Measure of a physical quantity, e.g., length,time, mass

Units: Assignment of a number to a dimension, e.g., (m),(sec), (kg)

7 Primary Dimensions:

1. Mass m (kg)2. Length L (m)

3. Time t (sec)

4. Temperature T (K)5. Current I (A)

6. Amount of Light C (cd)

7. Amount of matter N (mol)


5/96

Dimensions and Units

Review, continued

All non-primary dimensions can be formed by acombination of the 7 primary dimensions

Examples

{Velocity} = {Length/Time} = {L/t} {Force} = {Mass Length/Time2} = {mL/t2}


6/96

Dimensional Homogeneity

Law of dimensional homogeneity (DH): every additive termin an equation must have the same dimensions

Example: Bernoulli equation

{p} = {force/area}={mass x length/time2 x 1/length2} = {m/(t2L)}

{1/2V2} = {mass/length3 x (length/time)2} = {m/(t2L)}

{gz} = {mass/length3 x length/time2 x length} ={m/(t2L)}


7/96

Non dimensionalization of Equations

Given the law of DH, if we divide each term in

the equation by a collection of variables andconstants that have the same dimensions, the

equation is rendered nondimensional

In the process of nondimensionalizing an

equation, nondimensional parameters oftenappear, e.g., Reynolds number and Froude

number etc.


8/96

Nondimensionalization of Equations

To nondimensionalize, for example, the Bernoulliequation, the first step is to list primary dimensionsof all dimensional variables and constants

{p} = {m/(t2L)} {} = {m/L3} {V}= {L/t}

{g} = {L/t2

} {z} = {L}

Next, we need to select Scaling Parameters. For thisexample, selectL, U

0,

0


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By inspection, nondimensionalize all variables withscaling parameters

Back-substitutep, , V, g, z into dimensionalequation


10/96


Divide by 0U02

and set * = 1 (incompressibleflow)

Since g* = 1/Fr2, where


11/96


Note that convention often dictates many of the

nondimensional parameters, e.g., 1/20U02 is typically used to

nondimensionalize pressure.

This results in a slightly different form of the nondimensionalequation

BE CAREFUL! Always double check definitions.


12/96


Advantages of nondimensionalization

Increases insight about key parameters Decreases number of parameters in the problem

Easier communication

Fewer experiments

Fewer simulations

Extrapolation of results to untested conditions


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Dimensional Analysis and Similarity

Nondimensionalization of an equation is useful onlywhen the equation is known!

In many real-world flows, the equations are eitherunknown or too difficult to solve.

Experimentation is the only method of obtaining reliableinformation

In most experiments, geometrically-scaled models areused (time and money).

Experimental conditions and results must be properlyscaled so that results are meaningful for the full-scaleprototype.

Dimensional Analysis


14/96

Dimensional Analysis and Similarity

Primary purposes of dimensional analysis

To generate nondimensional parameters that helpin the design of experiments (physical and/or

numerical) and in reporting of results

To obtain scaling laws so that prototype

performance can be predicted from model

performance. To predict trends in the relationship between

parameters.


15/96

Example

A steady stream of liquid in turbulent flow is heated by passing it through a long, straight heated pipe. The

temperature is assumed to be greater by a constant amount

than the average temperature of the fluid. It is desired to finda relationship that can be used to predict the rate of heat

transfer from the wall of the liquid.

( , , , , , , )Pq D V c k T A

= 2 1

1

3

1 1

1 1

1 1 1

cos

cosp

q heat flow per unit are HL t A

D Pipeinside diam L

V Average Velocity Lt

Liquid density ML

Liquid Vis ity ML t

c Liquid Vis ity HM t

k liquid thermal conductivity HL t T

T temperature differen

= =

= =

= =

= =

= =

= =

= = = ce


16/96

Example contd.

( ) ( ) ( ) ( ) ( ) ( ) ( )a b c d e f g

Pq D V c k T A

=

2 1 3a b b c c d d e e e f f f f gHL t L L t M L M L H M T H L t T T =

exp : 1

exp : 2 3

exp : 1

exp : 0

exp : 0

onents of H e f

onents of L a b c d f

onents of t b d f

onents of M c d e

onents of T e f g

= +

= +

=

= + = +

7 variables & 5 Unknowns so two variables must be retained, here b &

e are retained


17/96

Example contd.

So rearranging in terms of b & e

1 , 1, , , 1f e g d e b c b a b= = = = =

Substituting above values it becomes

( ) ( ) ( ) ( ) ( ) ( ) ( )1 1

,

,

b b b e b e e

P

b e

P P

P

qD V c k T

A

c cqD DV qD DV

Ak T k Ak T k

cq k T DV

A D k

=

=> = => =

=> =


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Fluids (liquids and gases) are a form of matter thatcannot achieve equilibrium under an applied shearstress but deform continuously, or flow, as long asshear stress is applied.

The fluid flow means the movement of materialsthrough certain bounded regions (pipe).

The study of fluid flow can be divided in to :1) Fluid Static : it deals with fluid at rest in equilibrium.

2) Fluid dynamic : it deals with fluid in motion.


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PROPERTIES OF FLUIDS

1.Viscosity. Viscosity is a property thatcharacterizes the flow behavior of a fluid,reflecting the resistance to the development ofvelocity gradients within the fluid. A fluid is

contained between two parallel planes each ofarea A m2 and distance h m apart. The upper

plane is subjected to a shear force ofFN andacquires a velocity of u m/sec relative to thelower plane. The shear stress, t, is F/A,N /m2.The velocity gradient or rate of shear is given

by u/h or, more generally, by the differentialcoefficient du/dy, where y is a distancemeasured in a direction perpendicular to the

direction of shear.. For gases, simple liquids,true solutions, and dilute disperse systems, therate of shear is proportional to the shear stress.


20/96

2.Compressibility.

Compressibility is the measure of the change in volume a

substance undergoes when a pressure is exerted on the

substance.

Liquids are generally considered to be incompressible. Forinstance, a pressure of 16,400 psi will cause a given

volume of water to decrease by only 5% from its volume at

atmospheric pressure. Gases on the other hand, are very compressible. The

volume of a gas can be readily changed by exerting an

external pressure on the gas


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3.Surface Tension. Surface tension, a property confined to a free surface and,

therefore, not applicable to gases, is derived from

unbalanced intermolecular forces near the surface of aliquid.

This may be expressed as the work necessary to increase

the surface by unit area. Although not normally important,it can become so if the free surface is present in a passageof small diameter orifice of tube.


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Fluid static's deals with the fluids at rest in equilibrium

Behavior of liquid at rest

Nature of pressure it exerts and the variation of pressure at different

layers

Pressure differences between layers of liquids

h1

h2

Point 1

Point 2

FLUID STATICS

STATICS CONTD


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Consider a column of liquid with two openings Which are provided at the

wall of the vessel at different height

The rate of flow through these opening s are different due to the

pressure exerted at the different height

Consider a stationary column the pressureps is acting on the surface of

the fluid, column is maintained at constant pressure by applying pressure

The force acting below and above the point 1 are evaluated

Substituting the force with pressure x area of cross section in the aboveequation

Force acting on the liquidAt point 1 = Force on the surface

+ Force excreted by the liquidAbove point 1

Pressure at point 1 x Area =

Pressure on the surface x area

+ mass x acceleration

STATICS CONTD.

STATICS CONTD


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P1s = P2s + volume x density x acceleration

= P2s + height x area x density x acceleration

P1s = P2s + h1 S g

Since surface area is same

P1 = Ps + h1 g

Pressure acting on point 2 may be written as

P2 = Ps + h1 g

Difference in the pressure is obtained by

P2 - P1 = g (Ps + h2 )( Ps + h1 ) g

P = (Ps + h2 Ps - h1 ) g= h g

STATICS CONTD.


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Fluid is in Motion


26/96

FLUID DYNAMICS

Fluid dynamics deals with the study of fluids in motion

This knowledge is important for liquids, gels, ointments

which will change their flow behavior when exposed to

different stress conditions

MIXING

FLOW THROUGH PIPES

FILLED IN CONTAINER


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Identification of type of flow is important in

Manufacture of dosage forms

Handling of drugs for administration

The flow of fluid through a closed channel can be

viscous orturbulentand it can be observed by Reynolds experiment

Glass tube is connected to reservoir of water, rate of flow of water is

adjusted by a valve, a reservoir of colored solution is connected to one

end of the glass tube with help of nozzle. colored solution is introducedinto the nozzle as fine stream

TYPES OF FLOW


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water

valve

Colored liquidLAMINAR OR VISCOUS FLOW

TYPES OF FLOW

TURBULENT FLOW


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TYPES OF FLOW


30/96

TYPES OF FLOW

TYPES OF FLOW


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Lam inar f low is one in which the fluid particles move in layers or

laminar with one layer sliding with other

There is no exchange of fluidparticles from one layer to other

When velocity of the water is increased the thread of the colored water

disappears and mass of the water gets uniformly colored, indicates completemixing of the solution and the flow of the fluid is called as tu rbu lent

f low

The velocity at which the fluid changes from laminar flow to turbulent flow

that velocity is called as c r it i c a l veloc i t y

TYPES OF FLOW

REYNOLDS NUMBER


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In Reynolds experiment the flow conditions are affected by

Diameter of pipe

Average velocity

Density of liquid

Viscosity of the fluid

This four factors are combined in one way as Reynolds number

Reynolds number is obtained by the following equation

Inertial forces are due to mass and the velocity of the fluid particles trying todiffuse the fluid particles

viscous force if the frictional force due to the viscosity of the fluid which

make the motion of the fluid in parallel.

INERTIAL FORCES= ------------------------------ =

VISCOUS FORCESMASS X ACCELERATION OF LIQUID FLOWING

----------------------------------------------------------SHEAR STRESS X AREA

REYNOLDS NUMBER

Du

TYPES OF FLOW


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At low velocities the inertial forces are less when compared to the frictional

forces

Resulting flow will be viscous in nature Other hand when inertial forces are predominant the fluid layers break up due to

the increase in velocity hence turbulent flow takesplace.

If Re < 2000 the flow I said to be laminar If Re > 4000 the flow is said to be turbulent

If Re lies between 2000 to 4000 the flow changebetween laminar to turbulent

TYPES OF FLOW

Laminar Flow:


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REYNOLDS NUMBER - < 2100

Laminar Flow:

1) layers of water flowing over one another at different speed with virtually no mixing between layers.

2) Fluid particles move in definite and observable paths or streamlines,3) The center layer moves faster and the layer near the walls moves slower.

Transition Flow:


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REYNOLDS NUMBER

Between 2100 and 4000

Turbulent Flow:


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1) layers of water mixes each other

. 2) Fluid particles move in different direction or not-streamlines,

REYNOLDS NUMBER - > 4000

APPLICATIONS


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Reynolds number is used to predict the nature of the flow Stocks law equation is modified to include Reynolds number to study the

rate of sedimentation in suspension

Variations in the velocity of flow across the cross section

When velocity is plotted against the distance from the wall following

conclusions can be drawn

The flow of fluid in the middle of the pipe is faster then the fluid near to

the wall

The velocity of fluid approaches zero as the pipe wall is approached

At the actual surface of the pipe wall the velocity of the fluid is zero

APPLICATIONS


38/96

Pipe wall

Relativedistancefrom

thecenter

ofthepipe

U / U max

Viscous flow

Turbulent flow

The velocity of the fluid is zero at the wall surface there should be somelayer in viscous flow near the pipe wall which acts as stagnant layer

if the flow is turbulent at the center and viscous at the surface a buffer

layer exist, this buffer layer changes between the viscous to turbulent flow

Measurement of pressure


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Measurement of pressure

Manometer is devices to measure differential pressureP.

3 type of manometers

Simple

Differential

Inclined

MANOMETERS


40/96

Manometers are the devices used for measuring the pressure difference

Different type of manometers are there they are

1) Simple manometer2) Differential manometer

3) Inclined manometer

SIMPLE MANOMETER


41/96

This manometer is the most commonly used one It consists of a glass U shaped tube filled with a liquid A- of density A kg

/meter cube and above A the arms are filled with liquid B of densityB

The liquid A and B are immiscible and the interference can be seen clearly If two different pressures are applied on the two arms the meniscus of the

one liquid will be higher than the other

Let pressure at point 1 will be P1 Pascal's and point 5 will be P2 Pascal's The pressure at point 2 can be written as

= P1+ (m + R ) B g(m + R ) = distance from 3 to 5

SIMPLE MANOMETER


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P1 P2

m

R

1

23

4

5

Liquid A

L

IQUID

B

SIMPLE MANOMETER


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Since the points 2 and 3 are at same height the pressureat 3 can be written as

Pressure at 3 =P1+ (m + R ) B g

Pressure at 4 can be written as

= P2 + gm B

or

= P1+ B ( m + R ) g- a R g

Both the equations should be equal

P2 + gm B = P1+ B ( m + R ) g- a R g

P1 P2 = gm B - B ( m + R) g + A R g

P = gm B - gm B - R B g + R A=R ( A- B )g

DIFFERENTIAL MANOMETERS


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These manometers are suitable for measurement of small pressure differences

It is also known as two FluidU- tube manometer

It contains two immiscible liquids A and B having nearly same densities

The U tube contains of enlarged chambers on both limbs,

Using the principle of simple manometer the pressure differences can be

written as

P =P1P2 =R (cA) g

DIFFERENTIAL MANOMETERS


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P1 P2

Liquid A

Liquid B

Liquid C1

2

3 4

5

6

7

a

b

R

INCLINED TUBE MANOMETERS


46/96

Many applications require accurate measurement of low pressure such as

drafts and very low differentials, primarily in air and gas installations.

In these applications the manometer is arranged with the indicating tube

inclined, as in Figure, therefore providing an expanded scale.

This enables the measurement of small pressure changes with increasedaccuracy.

P1P2 = g R ( A - B) sin

INCLINED TUBE MANOMETERS


47/96

BERNOULLI'S THEOREM


48/96

When the principals of the law of energy is applied to the flow of

the fluids the resulting equation is called Bernoulli's theorem

Consider a pump working under isothermal conditions between points A and

B

Bernoulli's theorem states that in a steady state the total energy per unit massconsists of pressure, kinetic and potential energies are constant

Pump

Friction energy = F

Kinetic energy = u2 / 2g

Pressure energy = Pa / Ag

BERNOULLI'S THEOREM


49/96

At point a one kilogram of liquid is assumed to be entering at this point,

pressure energy at joule can be written as

Pressure energy = Pa /g A

Where Pa = Pressure at point ag = Acceleration due to gravity

A = Density of the liquid

Potential energy of a body is defined as the energy possessed by

the body by the virtue of its position

Potential energy = XA

Kinetic energy of a body is defined as the energy possessed by the

body by virtue of its motion,

kinetic energy = UA2 / 2g

Total energy at point A = Pressure energy + Potential energy+ Kinetic

energy

BERNOULLI'S THEOREM


50/96

Total energy at point A = Pa /g A +XA + UA2 / 2g

According to the Bernoulli's theorem the total energy at point

A is constant

Total energy at point A = Pa /g A +XA + UA2

/ 2g = ConstantAfter the system reaches the steady state, whenever one kilogram of

liquid enters at point A, another one kilogram of liquid leaves at point B

Total energy at point B = PB /g B +XB + UB2 / 2g

INPOUT = OUT PUT

Pa /g A +XA + UA2 / 2g =PB /g B +XB + UB

2 / 2g

Theoretically all kids of the energies involved in fluid flow should be

accounted, pump has added certain amount of energy

Energy added by the pump = + wJ

BERNOULLI'S THEOREM


51/96

During the transport some energy is converted to heat due to frictional

Forces

Loss of energy due to friction in the line = FJ

Pa /g A +XA + UA2

/ 2g F + W = PB /g B +XB + UB2

/ 2gThis equation is called as Bernoulli's equation

Application

Used in the measurement of rate of fluid flow It applied in the working of the centrifugal pump, in this kinetic energy is

converted in to pressure.

ENERGY LOSS


52/96

According to the law of conversation of energy, energy

balance have to be properly calculated

fluids experiences energy losses in several ways while flowing through pipes, they are

Frictional losses

Losses in the fitting

Enlargement losses

Contraction losses

FRICTIONAL LOSSES


53/96

During flow of fluids frictional forces causes a loss in pressure. Type of

fluid flow also influences the losses.

In general pressure drop will be

PRESSURE DROP VELOCITY (u)

Density of fluid()

Length of the pipe (L)

1 / diameter of the pipe (D)

These relationships are proposed in Fanning equation for calculating

friction losses

Fanning equation p = 2fu2L / D

F = frictional factor

For viscous flow pressure drop Hagen Poiseullie equation

= 32 Lu/ D2

LOSSES IN FITTING


54/96

Fanning equation is applicable for the losses in straight pipe. When

fitting are introduced into a straight pipe, They cause disturbance in the

flow, Which result in the additional loss of energy

losses in fitting may be due to

Change in direction Change in the type of fittings

Equivalent fitting = Equivalent fitting x internal diameterFor globe valve = 300 x 50

= 15 meter

That means globe valve is equal to 15 meters straight line, so thislength is substituted in fanning equation

Tee fitting

Equivalent length = 90Globe valve equivalent length = 300

ENLARGEMENT LOSS


55/96

If the cross section of the pipe enlarges gradually, the fluid adapts itself

to the changed section with out any disturbance. So no loss of energy

If the cross section of the pipe changes suddenly then loss in energy is

observed due to eddies. These are greater at this point than straight line

pipe

Than u2< u1

For sudden enlargement = H = u1 u2 / 2g

H = loss of head due to sudden enlargement

CONTRACTION LOSSES


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If the cross section of the pipe is reduced suddenly the fluid floe is

disturbed, the diameter of the fluid stream is less than the initial colume this

point is known as vena contracta

Viscosity


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Viscosity is force required to cause two parallel liquidplanes in the fluid, one cm. apart and having unit area

to slide past one another with a relative viscosity

1cm/sec. Ab. Viscosity is difficult to measure, hence

relative viscosity is measured with reference to water.

Kinematic Viscosity = Absolute viscosity of fluid/Kinematic Viscosity = Absolute viscosity of fluid/

density of waterdensity of water

Type of Fluids as per Viscosity behavior


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Two type 1. Newtonian Flow

2. Non-Newtonian Flow A) Plastic Flow

B) Pseudo Plastic C) Dilatant

D) Thixotropic flow

Type of Fluids as per Viscosity behavior


59/96

1. Newtonian Flow :


60/96

When the shear stress is

proportional to the rate of

shear and if we plot shearstress vs. rate of shear, a

straight line passing

through origin will beobtained for a Newtonian

liq. And tan gives the

viscosity of the liq. E.g.Water, Benzene, Alcohol,

Glycerin, Chloroform.

= tan

Shear stress, T

RateofShearv

2. Non-Newtonian Flow


61/96

Rheology properties of heterogeneous

dispersion such as emulsion, suspension and

semisolid are more complex and do not obeyNewtons equation of flow

(=F/A / dv/dx ) and fail to show theproportionality.

A) Plastic Flow


62/96

The curve does not pass through theorigin.

The substance fails to flow when lessamt of stress is applied further increase

in stress lead to non-linear increase inshear rates which later get linearised.

The linear portion when extrapolated theintercepts the x-axis at a point calledyield value. This plastic flow behavelike a Newtonian flow above the yieldvalue.

E.g. concentrated flocculatedsuspension, Butter, Ointment.

Material that show plastic flow arecalled as a Bingham. Shear stress, T

RateofShearv

B) Pseudo plastic Flow

Th b i t th i i


63/96

The curve begins at the origin.

As the shear stress increases, theshear rate also increases but non-linearly.

E.g. Polymer

Tragacanth, M.C, Na. CMC, Na.

Alginate, Rubber Up on withdrawal of shear stress,

System revert to its original state

and hence viscosity increases. It iscalled as sol gel sol

phenomenon.

RateofShearv

Shear stress, T

Shear stress, T

Shear ratethinning

C)DilatantTh h hibiti dil t t fl i


64/96

The rheogram exhibiting dilatant flow isshown in figure. It exhibit shearthickening.

The system gets thickened uponincreasing rate of shearing.

Up on shearing volume expanded so

called dilatant. When the stress is removed, the system

returns to its initial state of fluidity.

E.g. suspension of starch in water,Kaolin (12%) in water, ZnO (30%) inwater.

RateofS

hearv

Shear stress, T

D) Thixotropic flow

N t iN t i N t i


65/96

NewtonianNewtonian

When rate of shear is reduced, the downcurve is identical and super imposable onthe up curve.

Non Newtonian ( Shear Thinning)Non Newtonian ( Shear Thinning)

When agitated and kept aside, it returns

to its original fluidity, but it takes longertime to recover. This behavior is knownas Thixotropic.

Gel to Sol to Gel E.g. gels of Aluminum Hydroxide

gels of Magnesium Hydroxide

Bentonite Suspension

RateofShearv

RateofShe

arv

Shear stress, T

Shear stress, T

Newtonian

Pseudo

plastic

plastic

Non Newtonian

MEASUREMENT OF RATE OF FLOW OF FLUIDS

When ever fluid are used in a process it is necessary to measure the


66/96

When ever fluid are used in a process it is necessary to measure the

rate at which the fluid is flowing through the pipe,

Methods of measurement are

Direct weighing or measuring

Hydrodynamic methods

Orifice meter

Venturi meter

Pitot meter

Rotameter

Direct displacement meter

The liquid flowing through a pipe is collected for specific

DIRECT WEIGHING OR MEASURING


67/96

The liquid flowing through a pipe is collected for specific

period at any point and weighed or measured, and the rate of flow can be

determined.

Gases can not be determined by this method

ORIFICE METER

Principle:

Orifice meter is a thin plate containing a narrow and sharp aperture.When a fluid stream is allowed to pass through a narrow constriction the

velocity of the fluid increase compared to up stream

This results in decrease in pressure drop and the difference in the

pressure may be read from a manometer

The velocity of the fluid at thin constriction may be written as

U0 =C 0 2g H

H = can be measured by manometer


68/96

H can be measured by manometer

C0 = constant

U0 = velocity of fluid at the point of orifice meter

CONSTRUCTION

It is consider to be a thin plate containing a sharp aperture through which

fluid flows

Normally it is placed between long straight pipes

For present discussion plate is introduced into pipe and manometer is

connected at points A and B

WORKING

Orifice meter is referred as the variable head meter, i.e it measure the

variation in the pressure across a fixed construction placed in the path of flow

ORIFICE METER


69/96

When fluid is allowed to pass through the orifice the velocity of the fluid at

ORIFICE METER


70/96

point B increase, as a result at point A pressure will be increased.

Difference in the pressure is measured by manometer

Bernoulli's equation is applied to point A and point B for experimental

conditions

U02 UA2 =C02g. H

U0 = velocity of fluid at orifice

UA = velocity of fluid at point A

C0 = constant

If the diameter of the orifice is 1/5 or less of the pipe diameter then UA is

neglected

Applications

Velocity at either of the point A and B can be measured

Volume of li uid flowin er hour can be determined

VENTURI METER


71/96

Inlet

section

Throat ofVenturi

manometer

VENTURI METER


72/96

U v = C v 2g . H

DISADVANTAGES

Expensive

Need technical export

Not flexible it is permanentAdvantages

Power loss is less

Head loss is negligible

PITOT TUBE


73/96

Construction

PITOT TUBE


74/96

It is also known as insertion tube

The size of the sensing element is small compared to the flow channel

One tube is perpendicular to the flow direction and the other is parallel to

the flow Two tubes are connected to the manometer

Hp = u2 /2g

Working

Tube are inserted in the flow shown is the figure

U2 = Cv 2g. H

coefficient of Pitot tube

PITOT TUBE


75/96

ROTAMETER


76/96

ROTAMETER


77/96

Construction

ROTAMETER


78/96

It consists of vertically tampered and transparent tube in which a plummet isplaced

During the flow the plummet rise due to variation in flow

The upper edge of the plummet is used as an index to note the reading

Working

As the flow is upward through the tapered tube the plummet rises and falls

depend on the flow rate

Greater the flow rate higher the rise

DIRECT DISPLACEMENT METER

Used for the measurement of domestic water supply

PRINCIPLEIn this a stream of water enters meter and strikes the moving meter,

the rate of rotation of the moving membrane is proportional to the velocity

of the fluid.

ROTAMETER


79/96

ValvesValves are used to control the rate of fluid in a pipe


80/96

Valves should withstand

Pressure

Temperature Distortion

it should made up of brass, iron, bronze, and cast iron

E.X

Plug clock valve

Globe valve

Gate valve

Diaphragm valve

Quick opening valve

Check valve

PLUG CLOCK VALVE


81/96

Cylindrical

bore

Conical

plug

Stem

It consists of casting body in to which a conical plug is fixed


82/96

The plug has an opening through liquid will flow

Packing material is included around the stem to close it

Uses

Used for handling of gases

Used for wide opening or complete closing

Dis advantages

Not suitable for water due to the material of which made

Some times plug will come out easily

For slight rotation also grate change in the flow so difficult to operate

GLOBE VALVE


83/96

disc

Globular body

GLOBE VALVE


84/96

Globe valve consists of a globular body with a horizontal internal

GLOBE VALVE


85/96

portion

Passage of fluid is through a circular opening which can be opened

and closed by inserting the disc

Disc is called as seating disc It can be rotated freely on the stem

Uses

This should be used in pipe with size not more than 50 millimeters

Disadvantage

Rust, discomfort in opening of valve due to sludge

GATE VALVE


86/96

GATE VALVE


87/96

GATE VALVE


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Wedge shaped inclined seat type of gate is commonly used, pressure

on the gate is controlling factor in large valves.

Two type of gate valves are there in non rising stem valve thread of the valve stem engages the gate.

Gate can be raised and lowered without movement of the stem.

In rising stem valve length of the stem is more and gate and stem

are single piece.

Advantages

Available in large sizes, different designs.

In minimizes the differential pressure during opening and closing.

Diaphragm valves It consists of flexible physical barrier, valves are made of natural rubber

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or synthetic rubber faced with Teflon These are more suitable for fluids containing suspended solids and it can

be easily sterilized.

Quick opening valves


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Pumps

Positive Displacement pumps

e.g. Reciprocating pump

Gear pump.

Non- Positive Displacement pump

e.g. Centrifugal pump

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PUMPS


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In positive displacement pumps, the fluid isdrawn in to the chamber and the definite quantity

of fluid is forced out through the outlet with a

pressure for each stroke.

Centrifugal pump deliver the volume of fluiddepending up on the discharge pressure.

The reciprocating pump has an enlargement

which moves to and fro in a stationary cylinder.

Reciprocating pump


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Diaphram pump


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Rotary pump


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Gear pump

Lobe pump

Vane pump

Gear pump


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Van pump


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Phenomenon+ +Intro+ +PKB

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