Fluid Mechanics for Chemical Quiz 3

1 / 50

Capacity of a rotary gear pump can be varied by___________?

Bleeding air into suction

Changing the speed of rotation

All A., B. and C.

Bypassing liquid from the suction or discharge line

2 / 50

Diaphragm pumps are used to transport__________?

Solids

Fluids

Liquids

Slurries

3 / 50

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

Is different for different fluids

Is at the centroid of the plane surface

Is independent of the specific weight of the fluid

Lies above the centroid of the plane surface

4 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure difference

Absolute pressure

Pressure gradient

5 / 50

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

Either above or below; depends on the liquid density

Below

Above

6 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

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

7 / 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.

8 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Ideal plastic

Pseudo plastic fluid

Dilatent fluid

9 / 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

BHP required by the pump

NPSH required

10 / 50

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

None of these

Loss of static head

Back flow through impeller

Loss of kinetic head

11 / 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

Data not sufficient to relate f1 & f2

f1 = f2

f1 < f2

12 / 50

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

None of these

Hagen-Poiseuille?s equation

Navier-stokes equation

Stoke?s law

13 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

Have quieter operation

All A., B. and C.

Require less space

14 / 50

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

Is independent of body length

Depends mainly on cross-sectional shape

Is primarily a friction drag

Occurs when NRe is very small

15 / 50

Check valves are used________?

For controlling water flow

In bends

For unidirectional flow

At high pressure

16 / 50

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

< 0.1

< 2100

< 500

> 2.5

17 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Atmospheric pressure

Pressure difference between two points

18 / 50

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

Develops high pressure

Increase in thrust

Decrease in effect

Develops noise

19 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T-2

L2T

MLT-1

20 / 50

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

d1/3

d4/5

d2/3

21 / 50

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

Equal to

Not related to

More than

Less than

22 / 50

Cp/Cv is termed as___________?

Weber number

Prandtl number

Adiabatic constant

Mach number

23 / 50

Cocks are used to control _____?

Solids

Any liquid

Water

None of these

24 / 50

Choking in case of pipe flow means that a_____?

Valve is closed in the line

Specified mass flow rate cannot be achieved

None of these

Restriction in flow cross-section area occurs

25 / 50

Cd is always _______ Cc?

Greater than

Less than

Equal to

Either more or less than

26 / 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

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

27 / 50

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

200 to 300

0.01 to 0.10

2 to 3

100 to 1000

28 / 50

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

FL-1

F-1. L

F-2. L

F.L-2

29 / 50

Dimension of absolute viscosity is__________?

MLT

ML-1T

ML-1T-1

MLT-1

30 / 50

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

All A., B. and C.

Flow of liquid during operation of the pump

Discharge pressure

Back flow of fluid in the event of stoppage of pump

31 / 50

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

d2/3

d1/3

32 / 50

Cd for the orifice plate varies from _____?

0.58 to 0.8

0.2 to 0.3

0.93 to 0.98

0.02 to 0.03

33 / 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) ?

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

ML-1T-3, F-1L2T

FLT, ML-1T-1

34 / 50

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

Inlet pressure low

Outlet pressure high

Inlet pressure high

Outlet pressure low

35 / 50

Critical velocity in a pipe flow__________?

None of these

Increases as pipe diameter increases

Increases as fluid viscosity increases

Independent of fluid density

36 / 50

Buoyant force___________?

None of these

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

37 / 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/?

38 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

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

Do not need priming

Run at a lower speed for the same discharge

Deliver fluid with pulsating/fluctuating discharge

39 / 50

Boundary layer separation occurs when the______?

Velocity of sound is reached

Pressure reaches a minimum

Cross-section of the channel is reduced

Valve is closed in a pipeline

40 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

41 / 50

Dean number is concerned with the______?

Psychrometry

Power consumption in agitated vessels

Fluid flow through helical pipes

Fluid-particle interaction

42 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Type of casing

Impeller blade angle

rpm

43 / 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

0.98

0.62

0.42

44 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Solid suspended

Non-Newtonian

Viscous

45 / 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

46 / 50

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

Volume available in the cylinder

Flow rate through accumulator

Rate of falling of ram

Amount of energy stored

47 / 50

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

Equal to the vapour pressure

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

Greater than the vapour pressure of the liquid at that temperature

48 / 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

49 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

50 / 50

Check valve is used for _________ flow?

Very precise control of

None of these

Multidirectional

Unidirectional

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