Fluid Mechanics for Chemical Quiz 3

1 / 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

2 / 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

FL-2T, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

3 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Valve is closed in a pipeline

Cross-section of the channel is reduced

Velocity of sound is reached

4 / 50

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

Outlet pressure low

Inlet pressure high

Outlet pressure high

Inlet pressure low

5 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Type of casing

Impeller blade angle

Number of blades in impeller

6 / 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

7 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T

L2T-2

L2T-1

8 / 50

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

F.L-2

F-1. L

FL-1

F-2. L

9 / 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

200 to 300

0.01 to 0.10

10 / 50

Capacity of a rotary gear pump can be varied by___________?

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

All A., B. and C.

Bleeding air into suction

11 / 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

Flow of liquid during operation of the pump

All A., B. and C.

Discharge pressure

12 / 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

0.42

0.98

0.62

13 / 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

14 / 50

Cocks are used to control _____?

Any liquid

None of these

Water

Solids

15 / 50

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

Is independent of the specific weight of the fluid

Is different for different fluids

Is at the centroid of the plane surface

Lies above the centroid of the plane surface

16 / 50

Centrifugal compressors compared to reciprocating compressors___________?

All A., B. and C.

Have lower operating costs

Require less space

Have quieter operation

17 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

Dilatent fluid

Pseudo plastic fluid

None of these

18 / 50

Cp/Cv is termed as___________?

Mach number

Weber number

Adiabatic constant

Prandtl number

19 / 50

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

< 2100

< 500

> 2.5

< 0.1

20 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

Run at a lower speed for the same discharge

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

Do not need priming

21 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Pressure difference between two points

Atmospheric pressure

22 / 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

Develops high pressure

Develops noise

Decrease in effect

23 / 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

24 / 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

25 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Viscous

Corrosive

Solid suspended

26 / 50

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

d2/3

d1/3

27 / 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

28 / 50

Dimension of absolute viscosity is__________?

ML-1T

MLT

MLT-1

ML-1T-1

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

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

31 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure difference

Absolute pressure

Pressure gradient

32 / 50

Check valves are used________?

For unidirectional flow

In bends

At high pressure

For controlling water flow

33 / 50

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

Is primarily a friction drag

Occurs when NRe is very small

Is independent of body length

Depends mainly on cross-sectional shape

34 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Psychrometry

Fluid flow through helical pipes

Fluid-particle interaction

35 / 50

Check in a centrifugal pump is_________?

All A., B. and C.

Provided in the discharge line

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

Generally a globe valve

36 / 50

Diaphragm pumps are used to transport__________?

Slurries

Fluids

Solids

Liquids

37 / 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

38 / 50

Cd for the orifice plate varies from _____?

0.02 to 0.03

0.2 to 0.3

0.93 to 0.98

0.58 to 0.8

39 / 50

Cd is always _______ Cc?

Equal to

Less than

Greater than

Either more or less than

40 / 50

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

Above

Below

Either above or below; depends on the liquid density

41 / 50

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

More than

Not related to

Equal to

Less than

42 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

None of these

Increases as fluid viscosity increases

Increases as pipe diameter increases

43 / 50

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

Navier-stokes equation

None of these

Stoke?s law

Hagen-Poiseuille?s equation

44 / 50

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

Loss of kinetic head

Loss of static head

None of these

Back flow through impeller

45 / 50

Choking in case of pipe flow means that a_____?

Restriction in flow cross-section area occurs

Valve is closed in the line

Specified mass flow rate cannot be achieved

None of these

46 / 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

Head of the liquid pumped

All A., B. and C.

NPSH required

47 / 50

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

Equal to the developed head

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

Less than the vapour pressure of the liquid at that temperature

48 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

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

Moderately viscous vegetable oil used in soap industry

Thick molten soap at 80?C

49 / 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

50 / 50

Check valve is used for _________ flow?

Multidirectional

Very precise control of

None of these

Unidirectional

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