Fluid Mechanics for Chemical Quiz 3

1 / 50

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

More than

Equal to

Not related to

Less than

2 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

Do not need priming

Run at a lower speed for the same discharge

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

3 / 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

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

4 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Pressure reaches a minimum

Velocity of sound is reached

Cross-section of the channel is reduced

5 / 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.

BHP required by the pump

NPSH required

Head of the liquid pumped

6 / 50

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

Less than the vapour pressure of the liquid at that temperature

Greater than the vapour pressure of the liquid at that temperature

Equal to the developed head

Equal to the vapour pressure

7 / 50

Diaphragm pumps are used to transport__________?

Fluids

Liquids

Solids

Slurries

8 / 50

Check valves are used________?

For unidirectional flow

For controlling water flow

In bends

At high pressure

9 / 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

10 / 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

11 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

Moderately viscous vegetable oil used in soap industry

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

Thick molten soap at 80?C

12 / 50

Cp/Cv is termed as___________?

Weber number

Adiabatic constant

Mach number

Prandtl number

13 / 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

14 / 50

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

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

Make the pipe joint leak-proof

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

15 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

Increases as fluid viscosity increases

None of these

Increases as pipe diameter increases

16 / 50

Cocks are used to control _____?

Any liquid

Water

Solids

None of these

17 / 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

18 / 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

19 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head = developed head

20 / 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

21 / 50

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

F.L-2

FL-1

F-2. L

F-1. L

22 / 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

Flow of liquid during operation of the pump

All A., B. and C.

Discharge pressure

23 / 50

Check in a centrifugal pump is_________?

Provided in the discharge line

Generally a globe valve

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

24 / 50

Dimension of kinematic viscosity is_______?

L2T-2

L2T-1

L2T

MLT-1

25 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

26 / 50

Cd is always _______ Cc?

Less than

Equal to

Greater than

Either more or less than

27 / 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

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

Buoyant force___________?

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

None of these

For non-symmetrical bodies is not vertical

30 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

Number of blades in impeller

rpm

Impeller blade angle

31 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

None of these

Dilatent fluid

Pseudo plastic fluid

32 / 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

Occurs when NRe is very small

Is primarily a friction drag

33 / 50

Check valve is used for _________ flow?

Very precise control of

Unidirectional

None of these

Multidirectional

34 / 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

35 / 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

Develops high pressure

Increase in thrust

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

Is different for different fluids

Is at the centroid of the plane surface

Lies above the centroid of the plane surface

37 / 50

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

Outlet pressure low

Inlet pressure high

Inlet pressure low

Outlet pressure high

38 / 50

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

Stoke?s law

Hagen-Poiseuille?s equation

Navier-stokes equation

None of these

39 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Power consumption in agitated vessels

Fluid-particle interaction

Psychrometry

40 / 50

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

< 0.1

> 2.5

< 500

< 2100

41 / 50

Capacity of a rotary gear pump can be varied by___________?

All A., B. and C.

Bleeding air into suction

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

42 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Solid suspended

Non-Newtonian

Corrosive

43 / 50

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

None of these

Back flow through impeller

Loss of kinetic head

Loss of static head

44 / 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

45 / 50

Differential manometer measures the_____?

Pressure gradient

Pressure difference

Gauge pressure

Absolute pressure

46 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have quieter operation

Require less space

Have lower operating costs

All A., B. and C.

47 / 50

Differential manometer measures the______?

None of these

Atmospheric pressure

Pressure difference between two points

Sub-atmospheric pressure

48 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T

ML-1T-1

MLT

49 / 50

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

Below

Above

Either above or below; depends on the liquid density

50 / 50

Cd for the orifice plate varies from _____?

0.58 to 0.8

0.02 to 0.03

0.93 to 0.98

0.2 to 0.3

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