Fluid Mechanics for Chemical Quiz 3

1 / 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

2 / 50

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

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

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

3 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.02 to 0.03

0.93 to 0.98

0.58 to 0.8

4 / 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

BHP required by the pump

NPSH required

All A., B. and C.

5 / 50

Cp/Cv is termed as___________?

Weber number

Prandtl number

Adiabatic constant

Mach number

6 / 50

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

Hagen-Poiseuille?s equation

None of these

Stoke?s law

Navier-stokes equation

7 / 50

Buoyant force___________?

For non-symmetrical bodies is not vertical

None of these

Depends on the depth of the submergence of the floating body

Depends on the weight of the floating body

8 / 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___________?

0.42

0.82

0.98

0.62

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

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

rpm

Number of blades in impeller

Impeller blade angle

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

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

F-1. L

FL-1

F.L-2

F-2. L

13 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-1

MLT-1

L2T-2

14 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

ML-1T

MLT-1

MLT

15 / 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

16 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Solid suspended

Corrosive

Non-Newtonian

17 / 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

18 / 50

Differential manometer measures the_____?

Pressure difference

Absolute pressure

Pressure gradient

Gauge pressure

19 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

None of these

Increases as pipe diameter increases

Increases as fluid viscosity increases

20 / 50

Check valves are used________?

In bends

At high pressure

For unidirectional flow

For controlling water flow

21 / 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

Greater than the vapour pressure of the liquid at that temperature

Equal to the developed head

22 / 50

Differential manometer measures the______?

Atmospheric pressure

Sub-atmospheric pressure

None of these

Pressure difference between two points

23 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid flow through helical pipes

Psychrometry

Fluid-particle interaction

24 / 50

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

All A., B. and C.

Flow of liquid during operation of the pump

Discharge pressure

Back flow of fluid in the event of stoppage of pump

25 / 50

Diaphragm pumps are used to transport__________?

Liquids

Solids

Slurries

Fluids

26 / 50

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

Outlet pressure high

Outlet pressure low

Inlet pressure high

Inlet pressure low

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

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

Rate of falling of ram

Amount of energy stored

Flow rate through accumulator

Volume available in the cylinder

29 / 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

30 / 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

F-1L2T-1, MLT-3

ML-1T-3, F-1L2T

FLT, ML-1T-1

31 / 50

Check valve is used for _________ flow?

Multidirectional

Unidirectional

Very precise control of

None of these

32 / 50

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

Below

Either above or below; depends on the liquid density

Above

33 / 50

Cd is always _______ Cc?

Greater than

Equal to

Either more or less than

Less than

34 / 50

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

More than

Not related to

Less than

Equal to

35 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

Require less space

All A., B. and C.

Have quieter operation

36 / 50

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

< 0.1

< 2100

> 2.5

< 500

37 / 50

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

0.01 to 0.10

100 to 1000

200 to 300

2 to 3

38 / 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

39 / 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, 20.7 inches of Hg

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

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

40 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

Pseudo plastic fluid

None of these

Dilatent fluid

41 / 50

Cocks are used to control _____?

Any liquid

Water

Solids

None of these

42 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

All A., B. and C.

Changing the speed of rotation

Bleeding air into suction

43 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

44 / 50

Choking in case of pipe flow means that a_____?

None of these

Restriction in flow cross-section area occurs

Valve is closed in the line

Specified mass flow rate cannot be achieved

45 / 50

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

d1/3

d2/3

46 / 50

Centrifugal pump can?t be used to pump _______?

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

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

None of the above

47 / 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 primarily a friction drag

Is independent of body length

48 / 50

Check in a centrifugal pump is_________?

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

All A., B. and C.

Generally a globe valve

49 / 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

Is independent of the specific weight of the fluid

Is different for different fluids

Lies above the centroid of the plane surface

50 / 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

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