Fluid Mechanics for Chemical Quiz 3

1 / 50

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

Flow rate through accumulator

Amount of energy stored

Rate of falling of ram

Volume available in the cylinder

2 / 50

Check in a centrifugal pump is_________?

All A., B. and C.

Provided in the discharge line

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

Generally a globe valve

3 / 50

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

d1/3

d2/3

d4/5

4 / 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

5 / 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

6 / 50

Dimension of absolute viscosity is__________?

MLT-1

MLT

ML-1T

ML-1T-1

7 / 50

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

Outlet pressure high

Inlet pressure low

Outlet pressure low

Inlet pressure high

8 / 50

Choking in case of pipe flow means that a_____?

None of these

Valve is closed in the line

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

9 / 50

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

Loss of static head

None of these

Loss of kinetic head

Back flow through impeller

10 / 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

100 to 1000

200 to 300

0.01 to 0.10

11 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

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

Run at a lower speed for the same discharge

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

12 / 50

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

1/?

1/d

13 / 50

Check valves are used________?

For unidirectional flow

In bends

For controlling water flow

At high pressure

14 / 50

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

Either above or below; depends on the liquid density

Above

Below

15 / 50

Diaphragm valves are used for handling ________ fluids?

Solid suspended

Corrosive

Viscous

Non-Newtonian

16 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Atmospheric pressure

Pressure difference between two points

17 / 50

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

> 2.5

< 500

< 0.1

< 2100

18 / 50

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

Discharge pressure

Flow of liquid during operation of the pump

All A., B. and C.

Back flow of fluid in the event of stoppage of pump

19 / 50

Cd for the orifice plate varies from _____?

0.02 to 0.03

0.58 to 0.8

0.93 to 0.98

0.2 to 0.3

20 / 50

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

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

Less than the vapour pressure of the liquid at that temperature

Equal to the developed head

21 / 50

Cocks are used to control _____?

None of these

Solids

Any liquid

Water

22 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

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

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

23 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have lower operating costs

Have quieter operation

All A., B. and C.

24 / 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

Is different for different fluids

Is at the centroid of the plane surface

Lies above the centroid of the plane surface

25 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Bleeding air into suction

Changing the speed of rotation

All A., B. and C.

26 / 50

Differential manometer measures the_____?

Pressure gradient

Absolute pressure

Pressure difference

Gauge pressure

27 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

None of these

Independent of fluid density

28 / 50

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

d2/3

d1/3

29 / 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

FLT, ML-1T-1

ML-1T-3, F-1L2T

FL-2T, ML-1T-1

30 / 50

Cp/Cv is termed as___________?

Prandtl number

Weber number

Mach number

Adiabatic constant

31 / 50

Diaphragm pumps are used to transport__________?

Liquids

Solids

Slurries

Fluids

32 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

33 / 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?

Head of the liquid pumped

All A., B. and C.

NPSH required

BHP required by the pump

34 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

Pseudo plastic fluid

Dilatent fluid

None of these

35 / 50

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

Stoke?s law

Hagen-Poiseuille?s equation

Navier-stokes equation

None of these

36 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Velocity of sound is reached

Cross-section of the channel is reduced

Valve is closed in a pipeline

37 / 50

Check valve is used for _________ flow?

None of these

Very precise control of

Unidirectional

Multidirectional

38 / 50

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

Equal to

Not related to

Less than

More than

39 / 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

40 / 50

Cavitation can be prevented by_________?

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

41 / 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

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 high pressure

Develops noise

Decrease in effect

43 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid-particle interaction

Fluid flow through helical pipes

Psychrometry

44 / 50

Buoyant force___________?

None of these

Depends on the weight of the floating body

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

45 / 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

0.42

0.62

46 / 50

Cd is always _______ Cc?

Equal to

Less than

Greater than

Either more or less than

47 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Number of blades in impeller

Impeller blade angle

Type of casing

48 / 50

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

Account for the pressure variation side the pipeline

Keep the pipe in proper orientation

Make the pipe joint leak-proof

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

49 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-1

MLT-1

L2T-2

50 / 50

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

F-2. L

FL-1

F-1. L

F.L-2

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