Fluid Mechanics for Chemical Quiz 3

1 / 50

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

Equal to

More than

Less than

Not related to

2 / 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

3 / 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

Make the pipe joint leak-proof

Keep the pipe in proper orientation

4 / 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

Lies above the centroid of the plane surface

Is at the centroid of the plane surface

Is different for different fluids

5 / 50

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

Flow rate through accumulator

Rate of falling of ram

Volume available in the cylinder

Amount of energy stored

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

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

8 / 50

Check valve is used for _________ flow?

Unidirectional

None of these

Multidirectional

Very precise control of

9 / 50

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

Inlet pressure low

Outlet pressure high

Inlet pressure high

Outlet pressure low

10 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

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

11 / 50

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

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

12 / 50

Centrifugal pump can?t be used to pump _______?

Moderately viscous vegetable oil used in soap industry

None of the above

Thick molten soap at 80?C

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

13 / 50

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

> 2.5

< 0.1

< 500

< 2100

14 / 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

15 / 50

Diaphragm pumps are used to transport__________?

Fluids

Slurries

Liquids

Solids

16 / 50

Cavitation can be prevented by_________?

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

17 / 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

100 to 1000

200 to 300

18 / 50

Differential manometer measures the______?

Pressure difference between two points

Atmospheric pressure

Sub-atmospheric pressure

None of these

19 / 50

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

Loss of kinetic head

Loss of static head

Back flow through impeller

None of these

20 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Type of casing

rpm

Impeller blade angle

21 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Power consumption in agitated vessels

Psychrometry

Fluid-particle interaction

22 / 50

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

None of these

Hagen-Poiseuille?s equation

Stoke?s law

Navier-stokes equation

23 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have quieter operation

Have lower operating costs

All A., B. and C.

24 / 50

Differential manometer measures the_____?

Gauge pressure

Absolute pressure

Pressure gradient

Pressure difference

25 / 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

26 / 50

Cocks are used to control _____?

Any liquid

Solids

None of these

Water

27 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

None of these

Independent of fluid density

28 / 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

29 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Non-Newtonian

Corrosive

Solid suspended

30 / 50

Check in a centrifugal pump is_________?

Generally a globe valve

Provided in the discharge line

All A., B. and C.

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

31 / 50

Cd is always _______ Cc?

Either more or less than

Less than

Equal to

Greater than

32 / 50

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

Either above or below; depends on the liquid density

Below

Above

33 / 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/?

34 / 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

35 / 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

36 / 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.

NPSH required

Head of the liquid pumped

BHP required by the pump

37 / 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

38 / 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

FLT, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

39 / 50

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

d1/3

d2/3

40 / 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

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

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

41 / 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

0.82

0.42

0.62

42 / 50

Buoyant force___________?

Depends on the depth of the submergence of the floating body

None of these

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

43 / 50

Check valves are used________?

In bends

At high pressure

For unidirectional flow

For controlling water flow

44 / 50

Curve III in the bellow diagram represents a/an_________?

Dilatent fluid

Ideal plastic

None of these

Pseudo plastic fluid

45 / 50

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

F.L-2

FL-1

F-1. L

F-2. L

46 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T-1

MLT

ML-1T

47 / 50

Cd for the orifice plate varies from _____?

0.02 to 0.03

0.58 to 0.8

0.2 to 0.3

0.93 to 0.98

48 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-2

L2T

L2T-1

49 / 50

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

Is independent of body length

Depends mainly on cross-sectional shape

Is primarily a friction drag

Occurs when NRe is very small

50 / 50

Cp/Cv is termed as___________?

Weber number

Prandtl number

Adiabatic constant

Mach number

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