Fluid Mechanics for Chemical Quiz 3

1 / 50

Check valve is used for _________ flow?

Multidirectional

Unidirectional

Very precise control of

None of these

2 / 50

Cp/Cv is termed as___________?

Prandtl number

Mach number

Adiabatic constant

Weber number

3 / 50

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

< 0.1

< 500

< 2100

> 2.5

4 / 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

0.62

0.98

0.42

5 / 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

6 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head lower than the vapour pressure

7 / 50

Cocks are used to control _____?

Water

Any liquid

None of these

Solids

8 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Cross-section of the channel is reduced

Pressure reaches a minimum

Velocity of sound is reached

9 / 50

Cd is always _______ Cc?

Greater than

Either more or less than

Less than

Equal to

10 / 50

Critical velocity in a pipe flow__________?

Increases as pipe diameter increases

Independent of fluid density

None of these

Increases as fluid viscosity increases

11 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

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

Run at a lower speed for the same discharge

12 / 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) ?

ML-1T-3, F-1L2T

FLT, ML-1T-1

FL-2T, ML-1T-1

F-1L2T-1, MLT-3

13 / 50

Diaphragm pumps are used to transport__________?

Slurries

Solids

Fluids

Liquids

14 / 50

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

None of these

Stoke?s law

Hagen-Poiseuille?s equation

Navier-stokes equation

15 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Viscous

Corrosive

Solid suspended

16 / 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

17 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

18 / 50

Centrifugal pump can?t be used to pump _______?

Moderately viscous vegetable oil used in soap industry

None of the above

Thick molten soap at 80?C

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

19 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

rpm

Impeller blade angle

Type of casing

20 / 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

All A., B. and C.

Flow of liquid during operation of the pump

Discharge pressure

21 / 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

22 / 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

23 / 50

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

Occurs when NRe is very small

Depends mainly on cross-sectional shape

Is independent of body length

Is primarily a friction drag

24 / 50

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

Equal to the developed head

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 vapour pressure

25 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-2

L2T

L2T-1

26 / 50

Buoyant force___________?

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

None of these

27 / 50

Dimension of absolute viscosity is__________?

ML-1T

ML-1T-1

MLT-1

MLT

28 / 50

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

Below

Above

Either above or below; depends on the liquid density

29 / 50

Curve III in the bellow diagram represents a/an_________?

Dilatent fluid

Pseudo plastic fluid

None of these

Ideal plastic

30 / 50

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

Back flow through impeller

Loss of kinetic head

None of these

Loss of static head

31 / 50

Capacity of a rotary gear pump can be varied by___________?

Bleeding air into suction

Bypassing liquid from the suction or discharge line

All A., B. and C.

Changing the speed of rotation

32 / 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?

NPSH required

BHP required by the pump

Head of the liquid pumped

All A., B. and C.

33 / 50

Check valves are used________?

In bends

At high pressure

For unidirectional flow

For controlling water flow

34 / 50

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

Volume available in the cylinder

Amount of energy stored

Flow rate through accumulator

Rate of falling of ram

35 / 50

Centrifugal compressors compared to reciprocating compressors___________?

All A., B. and C.

Have quieter operation

Require less space

Have lower operating costs

36 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure gradient

Absolute pressure

Pressure difference

37 / 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

Increase in thrust

Develops high pressure

Decrease in effect

38 / 50

Differential manometer measures the______?

Sub-atmospheric pressure

None of these

Pressure difference between two points

Atmospheric pressure

39 / 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

40 / 50

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

d1/3

d2/3

41 / 50

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

Inlet pressure high

Outlet pressure low

Outlet pressure high

Inlet pressure low

42 / 50

Check in a centrifugal pump is_________?

All A., B. and C.

Generally a globe valve

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

Provided in the discharge line

43 / 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

44 / 50

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

F.L-2

F-1. L

F-2. L

FL-1

45 / 50

Choking in case of pipe flow means that a_____?

Valve is closed in the line

None of these

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

46 / 50

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

100 to 1000

0.01 to 0.10

2 to 3

200 to 300

47 / 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 ?

Data not sufficient to relate f1 & f2

f1 > f2

f1 = f2

f1 < f2

48 / 50

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

More than

Not related to

Less than

Equal to

49 / 50

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

Lies above the centroid of the plane surface

Is different for different fluids

Is at the centroid of the plane surface

Is independent of the specific weight of the fluid

50 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Psychrometry

Fluid-particle interaction

Fluid flow through helical pipes

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