Fluid Mechanics for Chemical Quiz 3

1 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-1

L2T

L2T-2

2 / 50

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

None of these

Stoke?s law

Navier-stokes equation

Hagen-Poiseuille?s equation

3 / 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

2 to 3

200 to 300

4 / 50

Cocks are used to control _____?

None of these

Any liquid

Solids

Water

5 / 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

Generally a globe valve

All A., B. and C.

6 / 50

Choose the set of pressure intensities that are equivalent ?

4.33 psi, 10 ft. of water, 8.83 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

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

7 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

Maintaining the suction head sufficiently greater than the vapour pressure

8 / 50

Check valve is used for _________ flow?

None of these

Unidirectional

Multidirectional

Very precise control of

9 / 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

Keep the pipe in proper orientation

Make the pipe joint leak-proof

10 / 50

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

None of these

Back flow through impeller

Loss of static head

Loss of kinetic head

11 / 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?

All A., B. and C.

Head of the liquid pumped

BHP required by the pump

NPSH required

12 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Run at a lower speed for the same discharge

Deliver fluid with pulsating/fluctuating discharge

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

Do not need priming

13 / 50

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

d2/3

d1/3

d4/5

14 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Impeller blade angle

Number of blades in impeller

Type of casing

15 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Solid suspended

Non-Newtonian

Corrosive

16 / 50

Differential manometer measures the______?

Pressure difference between two points

Atmospheric pressure

None of these

Sub-atmospheric pressure

17 / 50

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

F.L-2

F-2. L

F-1. L

FL-1

18 / 50

Cp/Cv is termed as___________?

Adiabatic constant

Prandtl number

Weber number

Mach number

19 / 50

Boundary layer separation occurs when the______?

Velocity of sound is reached

Valve is closed in a pipeline

Pressure reaches a minimum

Cross-section of the channel is reduced

20 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure gradient

Pressure difference

Absolute pressure

21 / 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

22 / 50

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

Outlet pressure low

Inlet pressure low

Outlet pressure high

Inlet pressure high

23 / 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

0.42

0.62

24 / 50

Buoyant force___________?

None of these

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

25 / 50

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

Volume available in the cylinder

Rate of falling of ram

Amount of energy stored

Flow rate through accumulator

26 / 50

Check valves are used________?

At high pressure

In bends

For controlling water flow

For unidirectional flow

27 / 50

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

Above

Either above or below; depends on the liquid density

Below

28 / 50

Centrifugal compressors compared to reciprocating compressors___________?

All A., B. and C.

Require less space

Have lower operating costs

Have quieter operation

29 / 50

Cd is always _______ Cc?

Less than

Either more or less than

Equal to

Greater than

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

ML-1T-3, F-1L2T

FLT, ML-1T-1

F-1L2T-1, MLT-3

31 / 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

Is primarily a friction drag

Depends mainly on cross-sectional shape

32 / 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

33 / 50

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

Discharge pressure

All A., B. and C.

Flow of liquid during operation of the pump

Back flow of fluid in the event of stoppage of pump

34 / 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/?

35 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Fluid flow through helical pipes

Psychrometry

Power consumption in agitated vessels

36 / 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

37 / 50

Curve III in the bellow diagram represents a/an_________?

Pseudo plastic fluid

None of these

Dilatent fluid

Ideal plastic

38 / 50

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

Equal to

Less than

More than

Not related to

39 / 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

40 / 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

41 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

All A., B. and C.

Bleeding air into suction

Changing the speed of rotation

42 / 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

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

43 / 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

44 / 50

Diaphragm pumps are used to transport__________?

Liquids

Slurries

Fluids

Solids

45 / 50

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

d2/3

d1/3

46 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

Increases as fluid viscosity increases

None of these

Increases as pipe diameter increases

47 / 50

Dimension of absolute viscosity is__________?

MLT

MLT-1

ML-1T

ML-1T-1

48 / 50

Centrifugal pump can?t be used to pump _______?

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

None of the above

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

49 / 50

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

< 500

< 0.1

> 2.5

< 2100

50 / 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 at the centroid of the plane surface

Is independent of the specific weight of the fluid

Lies above the centroid of the plane surface

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