Fluid Mechanics for Chemical Quiz 3

1 / 50

Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about___________?

0.82

0.62

0.42

0.98

2 / 50

Check in a centrifugal pump is_________?

All A., B. and C.

Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running

Provided in the discharge line

Generally a globe valve

3 / 50

Buckingham-? theorem states that in any physical problem including ?n? quantities having ?m? dimensions, the quantities can be arranged into ______ independent dimensionless parameters?

n/m

n-m

4 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

Impeller blade angle

rpm

Number of blades in impeller

5 / 50

Centre of pressure in an immersed body is _______ the centre of gravity?

Above

Either above or below; depends on the liquid density

Below

6 / 50

Cocks are used to control _____?

Water

Solids

None of these

Any liquid

7 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Ideal plastic

Pseudo plastic fluid

Dilatent fluid

8 / 50

Dimension of surface tension is (where, F = force, L = length) ?

FL-1

F-1. L

F.L-2

F-2. L

9 / 50

Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?

Data not sufficient to relate f1 & f2

f1 < f2

f1 = f2

f1 > f2

10 / 50

Choose the set of pressure intensities that are equivalent ?

4.33 psi, 10 ft. of water, 8.83 inches of Hg

4.33 psi, 10 ft. of water, 20.7 inches of Hg

10 psi, 19.7 ft. of water, 23.3 inches of Hg

10 psi, 19.7 ft. of water, 5.3 inches of Hg

11 / 50

Disc compensators are provided in large diameter fuel gas carrying pipelines to__________?

Keep the pipe in proper orientation

Account for contraction/expansion of pipe due to temperature changes of the surroundings

Make the pipe joint leak-proof

Account for the pressure variation side the pipeline

12 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid-particle interaction

Psychrometry

Fluid flow through helical pipes

13 / 50

Brownian movement is prominent in the particle size range of ______ microns in case of settling of a particle in a fluid?

100 to 1000

0.01 to 0.10

200 to 300

2 to 3

14 / 50

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the ________ decreases?

All A., B. and C.

Head of the liquid pumped

NPSH required

BHP required by the pump

15 / 50

Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.) ?

d2/3

d1/3

16 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT

ML-1T

MLT-1

17 / 50

Deformation drag, which is caused by widespread deformation of fluid around the immersed body______?

Is primarily a friction drag

Occurs when NRe is very small

Is independent of body length

Depends mainly on cross-sectional shape

18 / 50

Check valves are used________?

For controlling water flow

At high pressure

For unidirectional flow

In bends

19 / 50

Differential manometer measures the_____?

Pressure gradient

Pressure difference

Absolute pressure

Gauge pressure

20 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have quieter operation

All A., B. and C.

Require less space

Have lower operating costs

21 / 50

Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively) ?

FLT, ML-1T-1

F-1L2T-1, MLT-3

ML-1T-3, F-1L2T

FL-2T, ML-1T-1

22 / 50

Check valve is used for _________ flow?

Unidirectional

Multidirectional

Very precise control of

None of these

23 / 50

Differential manometer measures the______?

None of these

Pressure difference between two points

Sub-atmospheric pressure

Atmospheric pressure

24 / 50

Design of the casing of centrifugal pump should be such as to minimise the_________?

Loss of static head

Loss of kinetic head

None of these

Back flow through impeller

25 / 50

Creeping flow around a sphere is defined, when particle Reynolds number is_____?

> 2.5

< 0.1

< 500

< 2100

26 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

None of these

Increases as pipe diameter increases

Increases as fluid viscosity increases

27 / 50

Buoyant force___________?

None of these

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

28 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Non-Newtonian

Corrosive

Solid suspended

29 / 50

Cavitation in a centrifugal pump can be avoided by keeping the___________?

Outlet pressure high

Inlet pressure high

Outlet pressure low

Inlet pressure low

30 / 50

Cavitation occurs in a centrifugal pump when the suction pressure is_________?

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

31 / 50

Boundary layer separation occurs when the______?

Cross-section of the channel is reduced

Velocity of sound is reached

Valve is closed in a pipeline

Pressure reaches a minimum

32 / 50

Co-efficient of velocity is _____ the coefficient of discharge?

Less than

Not related to

More than

Equal to

33 / 50

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, ? = surface tension of mercury)______?

1/d

1/?

34 / 50

Dimension of kinematic viscosity is_______?

L2T-2

L2T-1

L2T

MLT-1

35 / 50

Capillary tube method of viscosity measurement is based on the _________?

Navier-stokes equation

Hagen-Poiseuille?s equation

Stoke?s law

None of these

36 / 50

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.) ?

d4/5

d1/3

d2/3

37 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

Can be run with discharge line valve closed for a short interval

Run at a lower speed for the same discharge

Deliver fluid with pulsating/fluctuating discharge

38 / 50

Cavitation can be prevented by_________?

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

39 / 50

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the________?

Discharge pressure

Back flow of fluid in the event of stoppage of pump

Flow of liquid during operation of the pump

All A., B. and C.

40 / 50

Diaphragm pumps are used to transport__________?

Fluids

Solids

Slurries

Liquids

41 / 50

Cp/Cv is termed as___________?

Prandtl number

Adiabatic constant

Mach number

Weber number

42 / 50

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

Increase in thrust

Develops noise

Decrease in effect

Develops high pressure

43 / 50

Capacity of a hydraulic accumulator is defined in terms of maximum_______?

Amount of energy stored

Volume available in the cylinder

Flow rate through accumulator

Rate of falling of ram

44 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

All A., B. and C.

Bleeding air into suction

45 / 50

Cd for the orifice plate varies from _____?

0.93 to 0.98

0.58 to 0.8

0.02 to 0.03

0.2 to 0.3

46 / 50

Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(?/D) + (1.26/NRe ?F). It reduces to Nikuradse equation for a value of (?/D) equal to ___________?

0.5

47 / 50

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid_________?

Lies above the centroid of the plane surface

Is independent of the specific weight of the fluid

Is different for different fluids

Is at the centroid of the plane surface

48 / 50

Choking in case of pipe flow means that a_____?

None of these

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

Valve is closed in the line

49 / 50

Cd is always _______ Cc?

Greater than

Either more or less than

Equal to

Less than

50 / 50

Centrifugal pump can?t be used to pump _______?

Thick molten soap at 80?C

None of the above

Moderately viscous vegetable oil used in soap industry

Molten sodium (used as a coolant in Fast Breeder Reactor)

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