Fluid Mechanics for Chemical Quiz 3

1 / 50

Cocks are used to control _____?

Water

Solids

Any liquid

None of these

2 / 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

NPSH required

All A., B. and C.

BHP required by the pump

3 / 50

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

> 2.5

< 0.1

< 2100

< 500

4 / 50

Capacity of a rotary gear pump can be varied by___________?

Bleeding air into suction

All A., B. and C.

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

5 / 50

Curve III in the bellow diagram represents a/an_________?

Pseudo plastic fluid

Dilatent fluid

None of these

Ideal plastic

6 / 50

Cd is always _______ Cc?

Equal to

Less than

Either more or less than

Greater than

7 / 50

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

None of these

Loss of kinetic head

Loss of static head

Back flow through impeller

8 / 50

Check in a centrifugal pump is_________?

Provided in the discharge line

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

Generally a globe valve

9 / 50

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

Flow rate through accumulator

Volume available in the cylinder

Rate of falling of ram

Amount of energy stored

10 / 50

Check valve is used for _________ flow?

Unidirectional

Very precise control of

None of these

Multidirectional

11 / 50

Diaphragm pumps are used to transport__________?

Solids

Liquids

Slurries

Fluids

12 / 50

Boundary layer separation occurs when the______?

Cross-section of the channel is reduced

Velocity of sound is reached

Valve is closed in a pipeline

Pressure reaches a minimum

13 / 50

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

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

14 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid-particle interaction

Fluid flow through helical pipes

Psychrometry

15 / 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

16 / 50

Choking in case of pipe flow means that a_____?

Restriction in flow cross-section area occurs

Valve is closed in the line

Specified mass flow rate cannot be achieved

None of these

17 / 50

Differential manometer measures the______?

Pressure difference between two points

None of these

Sub-atmospheric pressure

Atmospheric pressure

18 / 50

Critical velocity in a pipe flow__________?

None of these

Increases as pipe diameter increases

Independent of fluid density

Increases as fluid viscosity increases

19 / 50

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

None of these

Hagen-Poiseuille?s equation

Navier-stokes equation

Stoke?s law

20 / 50

Dimension of absolute viscosity is__________?

ML-1T

ML-1T-1

MLT-1

MLT

21 / 50

Cp/Cv is termed as___________?

Adiabatic constant

Mach number

Weber number

Prandtl number

22 / 50

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

Outlet pressure low

Inlet pressure low

Outlet pressure high

Inlet pressure high

23 / 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

Lies above the centroid of the plane surface

Is independent of the specific weight of the fluid

24 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

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

Deliver fluid with pulsating/fluctuating discharge

Run at a lower speed for the same discharge

25 / 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

f1 = f2

Data not sufficient to relate f1 & f2

26 / 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

27 / 50

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

Equal to

Less than

More than

Not related to

28 / 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

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

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

29 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Solid suspended

Viscous

Non-Newtonian

30 / 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

31 / 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

32 / 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

33 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.58 to 0.8

0.93 to 0.98

0.02 to 0.03

34 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T

L2T-2

MLT-1

35 / 50

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

Either above or below; depends on the liquid density

Below

Above

36 / 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

37 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Type of casing

Impeller blade angle

rpm

38 / 50

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

d2/3

d1/3

39 / 50

Buoyant force___________?

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

None of these

Depends on the weight of the floating body

40 / 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

Develops noise

Increase in thrust

Decrease in effect

41 / 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

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

Keep the pipe in proper orientation

42 / 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) ?

FL-2T, ML-1T-1

FLT, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

43 / 50

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

F-1. L

F.L-2

F-2. L

FL-1

44 / 50

Differential manometer measures the_____?

Pressure difference

Gauge pressure

Absolute pressure

Pressure gradient

45 / 50

Check valves are used________?

In bends

For controlling water flow

At high pressure

For unidirectional flow

46 / 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

47 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have lower operating costs

Have quieter operation

All A., B. and C.

48 / 50

Cavitation can be prevented by_________?

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

49 / 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

50 / 50

Centrifugal pump can?t be used to pump _______?

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

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

None of the above

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