Fluid Mechanics for Chemical Quiz 3

1 / 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

2 / 50

Cp/Cv is termed as___________?

Mach number

Weber number

Adiabatic constant

Prandtl number

3 / 50

Capacity of a rotary gear pump can be varied by___________?

All A., B. and C.

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

Bleeding air into suction

4 / 50

Cd is always _______ Cc?

Equal to

Less than

Greater than

Either more or less than

5 / 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

6 / 50

Centrifugal compressors compared to reciprocating compressors___________?

All A., B. and C.

Require less space

Have lower operating costs

Have quieter operation

7 / 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

All A., B. and C.

Provided in the discharge line

Generally a globe valve

8 / 50

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

rpm

Type of casing

Number of blades in impeller

9 / 50

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

All A., B. and C.

Back flow of fluid in the event of stoppage of pump

Flow of liquid during operation of the pump

Discharge pressure

10 / 50

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

d2/3

d1/3

11 / 50

Check valves are used________?

For unidirectional flow

At high pressure

In bends

For controlling water flow

12 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Power consumption in agitated vessels

Psychrometry

Fluid-particle interaction

13 / 50

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

200 to 300

2 to 3

100 to 1000

0.01 to 0.10

14 / 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

15 / 50

Choose the set of pressure intensities that are equivalent ?

10 psi, 19.7 ft. of water, 5.3 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

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

16 / 50

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

Flow rate through accumulator

Rate of falling of ram

Amount of energy stored

Volume available in the cylinder

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___________?

0.98

0.82

0.42

0.62

18 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

Moderately viscous vegetable oil used in soap industry

Thick molten soap at 80?C

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

19 / 50

Check valve is used for _________ flow?

Unidirectional

None of these

Very precise control of

Multidirectional

20 / 50

Cocks are used to control _____?

Any liquid

Solids

None of these

Water

21 / 50

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

Is independent of body length

Occurs when NRe is very small

Depends mainly on cross-sectional shape

Is primarily a friction drag

22 / 50

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

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

Keep the pipe in proper orientation

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

23 / 50

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

Outlet pressure low

Inlet pressure low

Outlet pressure high

Inlet pressure high

24 / 50

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

Loss of kinetic head

Back flow through impeller

None of these

Loss of static head

25 / 50

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

Equal to the developed head

Equal to the vapour pressure

Less than the vapour pressure of the liquid at that temperature

Greater than the vapour pressure of the liquid at that temperature

26 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Independent of fluid density

None of these

Increases as pipe diameter increases

27 / 50

Differential manometer measures the______?

Pressure difference between two points

None of these

Atmospheric pressure

Sub-atmospheric pressure

28 / 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

29 / 50

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, ? = surface tension of mercury)______?

1/d

1/?

30 / 50

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

Above

Either above or below; depends on the liquid density

Below

31 / 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

Data not sufficient to relate f1 & f2

f1 = f2

f1 < f2

32 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Velocity of sound is reached

Valve is closed in a pipeline

Cross-section of the channel is reduced

33 / 50

Buoyant force___________?

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

Depends on the weight of the floating body

None of these

34 / 50

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

< 500

> 2.5

< 2100

< 0.1

35 / 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

All A., B. and C.

Head of the liquid pumped

BHP required by the pump

36 / 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

37 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Dilatent fluid

Ideal plastic

Pseudo plastic fluid

38 / 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

Do not need priming

Run at a lower speed for the same discharge

39 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-1

MLT-1

L2T-2

40 / 50

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

F-2. L

F-1. L

F.L-2

FL-1

41 / 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

42 / 50

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

Equal to

Not related to

Less than

More than

43 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Non-Newtonian

Solid suspended

Corrosive

44 / 50

Diaphragm pumps are used to transport__________?

Fluids

Slurries

Liquids

Solids

45 / 50

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

d1/3

d2/3

d4/5

46 / 50

Differential manometer measures the_____?

Pressure gradient

Gauge pressure

Pressure difference

Absolute pressure

47 / 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

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

48 / 50

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

None of these

Navier-stokes equation

Stoke?s law

Hagen-Poiseuille?s equation

49 / 50

Dimension of absolute viscosity is__________?

ML-1T

MLT-1

ML-1T-1

MLT

50 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

None of these

Restriction in flow cross-section area occurs

Valve is closed in the line

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