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

Cp/Cv is termed as___________?

Adiabatic constant

Prandtl number

Weber number

Mach number

3 / 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 independent of the specific weight of the fluid

Is at the centroid of the plane surface

4 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

Valve is closed in the line

None of these

Restriction in flow cross-section area occurs

5 / 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

6 / 50

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

Equal to the developed head

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

7 / 50

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

Equal to

Not related to

More than

Less than

8 / 50

Cocks are used to control _____?

None of these

Any liquid

Solids

Water

9 / 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

Head of the liquid pumped

All A., B. and C.

BHP required by the pump

10 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have quieter operation

All A., B. and C.

Have lower operating costs

11 / 50

Dean number is concerned with the______?

Psychrometry

Power consumption in agitated vessels

Fluid-particle interaction

Fluid flow through helical pipes

12 / 50

Check in a centrifugal pump is_________?

All A., B. and C.

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

13 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Valve is closed in a pipeline

Velocity of sound is reached

Cross-section of the channel is reduced

14 / 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

15 / 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___________?

0.62

0.98

0.42

0.82

16 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

Thick molten soap at 80?C

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

Moderately viscous vegetable oil used in soap industry

17 / 50

Critical velocity in a pipe flow__________?

None of these

Increases as fluid viscosity increases

Independent of fluid density

Increases as pipe diameter increases

18 / 50

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

Occurs when NRe is very small

Is primarily a friction drag

Is independent of body length

Depends mainly on cross-sectional shape

19 / 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

20 / 50

Check valves are used________?

At high pressure

For unidirectional flow

For controlling water flow

In bends

21 / 50

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

< 500

> 2.5

< 2100

< 0.1

22 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

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

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

23 / 50

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

Stoke?s law

Hagen-Poiseuille?s equation

None of these

Navier-stokes equation

24 / 50

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

d2/3

d1/3

25 / 50

Cd is always _______ Cc?

Either more or less than

Greater than

Equal to

Less than

26 / 50

Differential manometer measures the______?

Pressure difference between two points

Sub-atmospheric pressure

None of these

Atmospheric pressure

27 / 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

2 to 3

0.01 to 0.10

200 to 300

28 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Solid suspended

Corrosive

Viscous

29 / 50

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

Amount of energy stored

Flow rate through accumulator

Rate of falling of ram

Volume available in the cylinder

30 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-1

L2T-2

L2T

31 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Pseudo plastic fluid

Dilatent fluid

Ideal plastic

32 / 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

33 / 50

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

Outlet pressure low

Outlet pressure high

Inlet pressure high

Inlet pressure low

34 / 50

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

Below

Either above or below; depends on the liquid density

Above

35 / 50

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

Increase in thrust

Decrease in effect

Develops high pressure

Develops noise

36 / 50

Diaphragm pumps are used to transport__________?

Slurries

Liquids

Fluids

Solids

37 / 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) ?

F-1L2T-1, MLT-3

ML-1T-3, F-1L2T

FLT, ML-1T-1

FL-2T, ML-1T-1

38 / 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

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

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

Type of casing

Number of blades in impeller

rpm

41 / 50

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

F.L-2

FL-1

F-2. L

F-1. L

42 / 50

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

Back flow through impeller

Loss of kinetic head

Loss of static head

None of these

43 / 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

44 / 50

Check valve is used for _________ flow?

Very precise control of

Unidirectional

None of these

Multidirectional

45 / 50

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

Account for the pressure variation side the pipeline

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

46 / 50

Buoyant force___________?

None of these

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

47 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

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

Do not need priming

48 / 50

Differential manometer measures the_____?

Pressure difference

Gauge pressure

Absolute pressure

Pressure gradient

49 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT

MLT-1

ML-1T

50 / 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

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