Fluid Mechanics for Chemical Quiz 3

1 / 50

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

Hagen-Poiseuille?s equation

None of these

Navier-stokes equation

Stoke?s law

2 / 50

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

FL-1

F-1. L

F-2. L

F.L-2

3 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid-particle interaction

Psychrometry

Fluid flow through helical pipes

4 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure gradient

Pressure difference

Absolute pressure

5 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head = developed head

6 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Solid suspended

Non-Newtonian

Corrosive

7 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT

ML-1T

MLT-1

8 / 50

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

Account for the pressure variation side the pipeline

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

Keep the pipe in proper orientation

Make the pipe joint leak-proof

9 / 50

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

Flow rate through accumulator

Amount of energy stored

Rate of falling of ram

Volume available in the cylinder

10 / 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

2 to 3

200 to 300

100 to 1000

11 / 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

0.62

0.42

0.82

12 / 50

Boundary layer separation occurs when the______?

Cross-section of the channel is reduced

Pressure reaches a minimum

Valve is closed in a pipeline

Velocity of sound is reached

13 / 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 independent of the specific weight of the fluid

Is at the centroid of the plane surface

Is different for different fluids

14 / 50

Diaphragm pumps are used to transport__________?

Solids

Liquids

Slurries

Fluids

15 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

None of these

Independent of fluid density

Increases as pipe diameter increases

16 / 50

Capacity of a rotary gear pump can be varied by___________?

Changing the speed of rotation

All A., B. and C.

Bypassing liquid from the suction or discharge line

Bleeding air into suction

17 / 50

Differential manometer measures the______?

Pressure difference between two points

Atmospheric pressure

None of these

Sub-atmospheric pressure

18 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T-2

L2T

MLT-1

19 / 50

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

Depends mainly on cross-sectional shape

Is independent of body length

Occurs when NRe is very small

Is primarily a friction drag

20 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

Do not need priming

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

Run at a lower speed for the same discharge

21 / 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/?

22 / 50

Buoyant force___________?

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

None of these

23 / 50

Cd is always _______ Cc?

Less than

Either more or less than

Equal to

Greater than

24 / 50

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

d1/3

d4/5

d2/3

25 / 50

Check valves are used________?

At high pressure

For unidirectional flow

For controlling water flow

In bends

26 / 50

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

d1/3

d2/3

27 / 50

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

Outlet pressure high

Inlet pressure low

Inlet pressure high

Outlet pressure low

28 / 50

Cocks are used to control _____?

Water

Solids

Any liquid

None of these

29 / 50

Check valve is used for _________ flow?

Very precise control of

Multidirectional

Unidirectional

None of these

30 / 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

BHP required by the pump

All A., B. and C.

Head of the liquid pumped

31 / 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

32 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

33 / 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

34 / 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

All A., B. and C.

Discharge pressure

Flow of liquid during operation of the pump

35 / 50

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

Greater than the vapour pressure of the liquid at that temperature

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

36 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

Require less space

Have quieter operation

All A., B. and C.

37 / 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

F-1L2T-1, MLT-3

ML-1T-3, F-1L2T

FL-2T, ML-1T-1

38 / 50

Check in a centrifugal pump is_________?

Generally a globe valve

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

All A., B. and C.

39 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.93 to 0.98

0.02 to 0.03

0.58 to 0.8

40 / 50

Centrifugal pump can?t be used to pump _______?

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

Moderately viscous vegetable oil used in soap industry

None of the above

Thick molten soap at 80?C

41 / 50

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

Above

Either above or below; depends on the liquid density

Below

42 / 50

Choking in case of pipe flow means that a_____?

None of these

Valve is closed in the line

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

43 / 50

Cp/Cv is termed as___________?

Mach number

Weber number

Prandtl number

Adiabatic constant

44 / 50

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

Back flow through impeller

Loss of kinetic head

Loss of static head

None of these

45 / 50

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

< 500

> 2.5

< 0.1

< 2100

46 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

rpm

Type of casing

Impeller blade angle

47 / 50

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

More than

Equal to

Less than

Not related to

48 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

Pseudo plastic fluid

Dilatent fluid

None of these

49 / 50

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

Decrease in effect

Increase in thrust

Develops noise

Develops high pressure

50 / 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

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