Fluid Mechanics for Chemical Quiz 3

1 / 50

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

Volume available in the cylinder

Rate of falling of ram

Amount of energy stored

Flow rate through accumulator

2 / 50

Check valves are used________?

In bends

For controlling water flow

At high pressure

For unidirectional flow

3 / 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

4 / 50

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

Develops noise

Develops high pressure

Increase in thrust

Decrease in effect

5 / 50

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

d2/3

d1/3

6 / 50

Diaphragm valves are used for handling ________ fluids?

Solid suspended

Viscous

Non-Newtonian

Corrosive

7 / 50

Cd is always _______ Cc?

Either more or less than

Equal to

Less than

Greater than

8 / 50

Cp/Cv is termed as___________?

Mach number

Weber number

Prandtl number

Adiabatic constant

9 / 50

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

Back flow of fluid in the event of stoppage of pump

Discharge pressure

Flow of liquid during operation of the pump

All A., B. and C.

10 / 50

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

Loss of kinetic head

Loss of static head

Back flow through impeller

None of these

11 / 50

Capacity of a rotary gear pump can be varied by___________?

Changing the speed of rotation

Bleeding air into suction

All A., B. and C.

Bypassing liquid from the suction or discharge line

12 / 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?

BHP required by the pump

Head of the liquid pumped

NPSH required

All A., B. and C.

13 / 50

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

Either above or below; depends on the liquid density

Below

Above

14 / 50

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

Depends mainly on cross-sectional shape

Occurs when NRe is very small

Is primarily a friction drag

Is independent of body length

15 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

Maintaining the suction head sufficiently greater than the vapour pressure

16 / 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

17 / 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

FL-2T, ML-1T-1

F-1L2T-1, MLT-3

ML-1T-3, F-1L2T

18 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

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

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

19 / 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

20 / 50

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

> 2.5

< 0.1

< 500

< 2100

21 / 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___________?

0.98

0.82

0.42

0.62

22 / 50

Buoyant force___________?

Depends on the depth of the submergence of the floating body

Depends on the weight of the floating body

None of these

For non-symmetrical bodies is not vertical

23 / 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

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

24 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-2

L2T-1

L2T

25 / 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

26 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

Number of blades in impeller

rpm

Impeller blade angle

27 / 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

200 to 300

100 to 1000

28 / 50

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

Outlet pressure low

Inlet pressure low

Inlet pressure high

Outlet pressure high

29 / 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

30 / 50

Differential manometer measures the_____?

Absolute pressure

Pressure gradient

Gauge pressure

Pressure difference

31 / 50

Cd for the orifice plate varies from _____?

0.93 to 0.98

0.2 to 0.3

0.02 to 0.03

0.58 to 0.8

32 / 50

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

Is at the centroid of the plane surface

Lies above the centroid of the plane surface

Is independent of the specific weight of the fluid

Is different for different fluids

33 / 50

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

d4/5

d2/3

d1/3

34 / 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.

35 / 50

Differential manometer measures the______?

Sub-atmospheric pressure

None of these

Pressure difference between two points

Atmospheric pressure

36 / 50

Cocks are used to control _____?

Solids

None of these

Any liquid

Water

37 / 50

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

Equal to

Less than

Not related to

More than

38 / 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

39 / 50

Diaphragm pumps are used to transport__________?

Liquids

Fluids

Slurries

Solids

40 / 50

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

F-1. L

F-2. L

FL-1

F.L-2

41 / 50

Choking in case of pipe flow means that a_____?

None of these

Specified mass flow rate cannot be achieved

Valve is closed in the line

Restriction in flow cross-section area occurs

42 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

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

43 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Velocity of sound is reached

Valve is closed in a pipeline

Cross-section of the channel is reduced

44 / 50

Critical velocity in a pipe flow__________?

Increases as pipe diameter increases

None of these

Increases as fluid viscosity increases

Independent of fluid density

45 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

All A., B. and C.

Require less space

Have quieter operation

46 / 50

Dean number is concerned with the______?

Psychrometry

Fluid-particle interaction

Fluid flow through helical pipes

Power consumption in agitated vessels

47 / 50

Check valve is used for _________ flow?

Unidirectional

Multidirectional

Very precise control of

None of these

48 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Dilatent fluid

Ideal plastic

Pseudo plastic fluid

49 / 50

Dimension of absolute viscosity is__________?

MLT

ML-1T-1

MLT-1

ML-1T

50 / 50

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

Hagen-Poiseuille?s equation

None of these

Stoke?s law

Navier-stokes equation

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