Fluid Mechanics for Chemical Quiz 3

1 / 50

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

< 500

< 0.1

< 2100

> 2.5

2 / 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 independent of the specific weight of the fluid

Lies above the centroid of the plane surface

Is at the centroid of the plane surface

3 / 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

4 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T

L2T-1

L2T-2

5 / 50

Check valve is used for _________ flow?

None of these

Multidirectional

Very precise control of

Unidirectional

6 / 50

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

d1/3

d2/3

7 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T

ML-1T-1

MLT

8 / 50

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

F-2. L

F-1. L

FL-1

F.L-2

9 / 50

Cd is always _______ Cc?

Either more or less than

Greater than

Equal to

Less than

10 / 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

11 / 50

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

Either above or below; depends on the liquid density

Above

Below

12 / 50

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

Volume available in the cylinder

Rate of falling of ram

Flow rate through accumulator

Amount of energy stored

13 / 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?

BHP required by the pump

All A., B. and C.

NPSH required

Head of the liquid pumped

14 / 50

Buoyant force___________?

Depends on the weight of the floating body

None of these

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

15 / 50

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

None of these

Hagen-Poiseuille?s equation

Navier-stokes equation

Stoke?s law

16 / 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

Decrease in effect

Increase in thrust

Develops noise

17 / 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

FL-2T, ML-1T-1

FLT, ML-1T-1

F-1L2T-1, MLT-3

18 / 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

19 / 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

0.01 to 0.10

2 to 3

100 to 1000

20 / 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

21 / 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

22 / 50

Differential manometer measures the______?

Pressure difference between two points

None of these

Atmospheric pressure

Sub-atmospheric pressure

23 / 50

Capacity of a rotary gear pump can be varied by___________?

Bleeding air into suction

All A., B. and C.

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

24 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Run at a lower speed for the same discharge

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

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

25 / 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

26 / 50

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

Less than

Not related to

Equal to

More than

27 / 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

28 / 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

Data not sufficient to relate f1 & f2

f1 > f2

29 / 50

Check valves are used________?

At high pressure

For unidirectional flow

In bends

For controlling water flow

30 / 50

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

Loss of static head

Loss of kinetic head

None of these

Back flow through impeller

31 / 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

32 / 50

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

Depends mainly on cross-sectional shape

Is primarily a friction drag

Occurs when NRe is very small

Is independent of body length

33 / 50

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

All A., B. and C.

Discharge pressure

Back flow of fluid in the event of stoppage of pump

Flow of liquid during operation of the pump

34 / 50

Cocks are used to control _____?

Water

None of these

Solids

Any liquid

35 / 50

Choking in case of pipe flow means that a_____?

Restriction in flow cross-section area occurs

None of these

Valve is closed in the line

Specified mass flow rate cannot be achieved

36 / 50

Differential manometer measures the_____?

Absolute pressure

Pressure gradient

Pressure difference

Gauge pressure

37 / 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

0.98

0.62

0.42

38 / 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

39 / 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

40 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid-particle interaction

Psychrometry

Fluid flow through helical pipes

41 / 50

Centrifugal compressors compared to reciprocating compressors___________?

All A., B. and C.

Require less space

Have lower operating costs

Have quieter operation

42 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Type of casing

Impeller blade angle

rpm

43 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

Pseudo plastic fluid

None of these

Dilatent fluid

44 / 50

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

Outlet pressure high

Outlet pressure low

Inlet pressure high

Inlet pressure low

45 / 50

Diaphragm pumps are used to transport__________?

Solids

Liquids

Fluids

Slurries

46 / 50

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

Less than the vapour pressure of the liquid at that temperature

Greater than the vapour pressure of the liquid at that temperature

Equal to the developed head

Equal to the vapour pressure

47 / 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

48 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

Independent of fluid density

None of these

49 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Solid suspended

Non-Newtonian

Viscous

50 / 50

Cp/Cv is termed as___________?

Mach number

Adiabatic constant

Weber number

Prandtl number

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