Fluid Mechanics for Chemical Quiz 3

1 / 50

Centrifugal pump can?t be used to pump _______?

Thick molten soap at 80?C

None of the above

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

Moderately viscous vegetable oil used in soap industry

2 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

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

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

3 / 50

Differential manometer measures the_____?

Pressure gradient

Pressure difference

Absolute pressure

Gauge pressure

4 / 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

5 / 50

Check valves are used________?

For controlling water flow

In bends

At high pressure

For unidirectional flow

6 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

Bleeding air into suction

All A., B. and C.

7 / 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) ?

ML-1T-3, F-1L2T

FLT, ML-1T-1

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

8 / 50

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

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Less than the vapour pressure of the liquid at that temperature

9 / 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

0.42

0.62

0.98

10 / 50

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

< 0.1

> 2.5

< 500

< 2100

11 / 50

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

Make the pipe joint leak-proof

Account for the pressure variation side the pipeline

Keep the pipe in proper orientation

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

12 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Fluid flow through helical pipes

Psychrometry

Power consumption in agitated vessels

13 / 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/?

14 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Cross-section of the channel is reduced

Velocity of sound is reached

Pressure reaches a minimum

15 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Non-Newtonian

Solid suspended

Corrosive

16 / 50

Check in a centrifugal pump is_________?

Provided in the discharge line

Generally a globe valve

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

All A., B. and C.

17 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.02 to 0.03

0.58 to 0.8

0.93 to 0.98

18 / 50

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

d1/3

d2/3

19 / 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

20 / 50

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

Less than

Not related to

Equal to

More than

21 / 50

Check valve is used for _________ flow?

Very precise control of

Unidirectional

Multidirectional

None of these

22 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T

MLT-1

L2T-2

23 / 50

Buoyant force___________?

Depends on the depth of the submergence of the floating body

Depends on the weight of the floating body

For non-symmetrical bodies is not vertical

None of these

24 / 50

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

Outlet pressure low

Outlet pressure high

Inlet pressure high

Inlet pressure low

25 / 50

Cd is always _______ Cc?

Equal to

Less than

Greater than

Either more or less than

26 / 50

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

Decrease in effect

Develops noise

Increase in thrust

Develops high pressure

27 / 50

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

F-2. L

F-1. L

F.L-2

FL-1

28 / 50

Critical velocity in a pipe flow__________?

None of these

Independent of fluid density

Increases as pipe diameter increases

Increases as fluid viscosity increases

29 / 50

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

rpm

Type of casing

Number of blades in impeller

30 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Run at a lower speed for the same discharge

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

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

31 / 50

Cp/Cv is termed as___________?

Mach number

Adiabatic constant

Weber number

Prandtl number

32 / 50

Differential manometer measures the______?

Pressure difference between two points

Atmospheric pressure

Sub-atmospheric pressure

None of these

33 / 50

Cocks are used to control _____?

Water

Solids

Any liquid

None of these

34 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT-1

MLT

ML-1T

35 / 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?

NPSH required

BHP required by the pump

Head of the liquid pumped

All A., B. and C.

36 / 50

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

Is independent of the specific weight of the fluid

Lies above the centroid of the plane surface

Is at the centroid of the plane surface

Is different for different fluids

37 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

Have quieter operation

Require less space

All A., B. and C.

38 / 50

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

d2/3

d4/5

d1/3

39 / 50

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

Loss of static head

Back flow through impeller

Loss of kinetic head

None of these

40 / 50

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

2 to 3

0.01 to 0.10

100 to 1000

200 to 300

41 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head = developed head

42 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

Valve is closed in the line

None of these

43 / 50

Diaphragm pumps are used to transport__________?

Solids

Fluids

Liquids

Slurries

44 / 50

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

Occurs when NRe is very small

Is primarily a friction drag

Is independent of body length

Depends mainly on cross-sectional shape

45 / 50

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

Discharge pressure

All A., B. and C.

Back flow of fluid in the event of stoppage of pump

Flow of liquid during operation of the pump

46 / 50

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

Below

Above

Either above or below; depends on the liquid density

47 / 50

Curve III in the bellow diagram represents a/an_________?

Pseudo plastic fluid

None of these

Dilatent fluid

Ideal plastic

48 / 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 ?

f1 = f2

f1 > f2

Data not sufficient to relate f1 & f2

f1 < f2

49 / 50

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

Rate of falling of ram

Flow rate through accumulator

Amount of energy stored

Volume available in the cylinder

50 / 50

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

None of these

Stoke?s law

Navier-stokes equation

Hagen-Poiseuille?s equation

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