Fluid Mechanics for Chemical Quiz 3

1 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Power consumption in agitated vessels

Psychrometry

Fluid-particle interaction

2 / 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 at the centroid of the plane surface

Is different for different fluids

Is independent of the specific weight of the fluid

3 / 50

Cd is always _______ Cc?

Either more or less than

Less than

Equal to

Greater than

4 / 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

5 / 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

Flow of liquid during operation of the pump

Back flow of fluid in the event of stoppage of pump

6 / 50

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

Hagen-Poiseuille?s equation

Stoke?s law

None of these

Navier-stokes equation

7 / 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

8 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

None of these

Independent of fluid density

9 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

All A., B. and C.

Have quieter operation

Have lower operating costs

10 / 50

Diaphragm pumps are used to transport__________?

Slurries

Fluids

Liquids

Solids

11 / 50

Diaphragm valves are used for handling ________ fluids?

Solid suspended

Corrosive

Viscous

Non-Newtonian

12 / 50

Cocks are used to control _____?

Solids

Any liquid

None of these

Water

13 / 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/?

14 / 50

Differential manometer measures the_____?

Gauge pressure

Absolute pressure

Pressure gradient

Pressure difference

15 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

None of these

Pseudo plastic fluid

Dilatent fluid

16 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

17 / 50

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

Keep the pipe in proper orientation

Make the pipe joint leak-proof

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

Account for the pressure variation side the pipeline

18 / 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

19 / 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

20 / 50

Cd for the orifice plate varies from _____?

0.93 to 0.98

0.2 to 0.3

0.58 to 0.8

0.02 to 0.03

21 / 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

22 / 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

23 / 50

Buoyant force___________?

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

None of these

Depends on the weight of the floating body

24 / 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

f1 > f2

Data not sufficient to relate f1 & f2

25 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-1

MLT-1

L2T-2

26 / 50

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

Outlet pressure high

Inlet pressure low

Outlet pressure low

Inlet pressure high

27 / 50

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

Develops noise

Develops high pressure

Increase in thrust

Decrease in effect

28 / 50

Differential manometer measures the______?

Sub-atmospheric pressure

Pressure difference between two points

Atmospheric pressure

None of these

29 / 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

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

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

30 / 50

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

F-2. L

F-1. L

FL-1

F.L-2

31 / 50

Check valve is used for _________ flow?

None of these

Unidirectional

Multidirectional

Very precise control of

32 / 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___________?

0.42

0.82

0.98

0.62

33 / 50

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

Below

Either above or below; depends on the liquid density

Above

34 / 50

Cp/Cv is termed as___________?

Weber number

Mach number

Prandtl number

Adiabatic constant

35 / 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

36 / 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

F-1L2T-1, MLT-3

FLT, ML-1T-1

ML-1T-3, F-1L2T

37 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Type of casing

Number of blades in impeller

Impeller blade angle

38 / 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

NPSH required

Head of the liquid pumped

All A., B. and C.

39 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

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

Deliver fluid with pulsating/fluctuating discharge

Run at a lower speed for the same discharge

40 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T-1

ML-1T

MLT

41 / 50

Check valves are used________?

In bends

At high pressure

For controlling water flow

For unidirectional flow

42 / 50

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

Volume available in the cylinder

Amount of energy stored

Rate of falling of ram

Flow rate through accumulator

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

Check in a centrifugal pump is_________?

Generally a globe valve

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

45 / 50

Choking in case of pipe flow means that a_____?

Restriction in flow cross-section area occurs

None of these

Specified mass flow rate cannot be achieved

Valve is closed in the line

46 / 50

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

Loss of kinetic head

None of these

Back flow through impeller

Loss of static head

47 / 50

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

Depends mainly on cross-sectional shape

Occurs when NRe is very small

Is independent of body length

Is primarily a friction drag

48 / 50

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

d2/3

d1/3

49 / 50

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

Equal to

Less than

Not related to

More than

50 / 50

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

< 0.1

< 2100

< 500

> 2.5

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