Fluid Mechanics for Chemical Quiz 3

1 / 50

Check valve is used for _________ flow?

Very precise control of

None of these

Multidirectional

Unidirectional

2 / 50

Differential manometer measures the_____?

Pressure difference

Absolute pressure

Pressure gradient

Gauge pressure

3 / 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

4 / 50

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

Equal to the vapour pressure

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

5 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have quieter operation

Require less space

Have lower operating costs

All A., B. and C.

6 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT

MLT-1

ML-1T

7 / 50

Diaphragm pumps are used to transport__________?

Fluids

Solids

Slurries

Liquids

8 / 50

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

Equal to

More than

Not related to

Less than

9 / 50

Cocks are used to control _____?

Any liquid

Water

None of these

Solids

10 / 50

Brownian movement is prominent in the particle size range of ______ microns in case of settling of a particle in a fluid?

2 to 3

100 to 1000

0.01 to 0.10

200 to 300

11 / 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

12 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Psychrometry

Fluid flow through helical pipes

Power consumption in agitated vessels

13 / 50

Cd is always _______ Cc?

Less than

Either more or less than

Equal to

Greater than

14 / 50

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

Inlet pressure low

Outlet pressure high

Outlet pressure low

Inlet pressure high

15 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

Bleeding air into suction

All A., B. and C.

16 / 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/?

17 / 50

Check in a centrifugal pump is_________?

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

All A., B. and C.

18 / 50

Check valves are used________?

In bends

For unidirectional flow

For controlling water flow

At high pressure

19 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Solid suspended

Viscous

Corrosive

20 / 50

Differential manometer measures the______?

Sub-atmospheric pressure

None of these

Atmospheric pressure

Pressure difference between two points

21 / 50

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

Below

Above

Either above or below; depends on the liquid density

22 / 50

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

rpm

Type of casing

Number of blades in impeller

23 / 50

Critical velocity in a pipe flow__________?

Increases as pipe diameter increases

Independent of fluid density

None of these

Increases as fluid viscosity increases

24 / 50

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

Rate of falling of ram

Volume available in the cylinder

Flow rate through accumulator

Amount of energy stored

25 / 50

Choking in case of pipe flow means that a_____?

None of these

Valve is closed in the line

Restriction in flow cross-section area occurs

Specified mass flow rate cannot be achieved

26 / 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) ?

ML-1T-3, F-1L2T

FLT, ML-1T-1

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

27 / 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

NPSH required

All A., B. and C.

28 / 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

29 / 50

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

d2/3

d1/3

30 / 50

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

> 2.5

< 2100

< 0.1

< 500

31 / 50

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

Occurs when NRe is very small

Depends mainly on cross-sectional shape

Is primarily a friction drag

Is independent of body length

32 / 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

33 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T

L2T-1

L2T-2

34 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Valve is closed in a pipeline

Velocity of sound is reached

Cross-section of the channel is reduced

35 / 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, 23.3 inches of Hg

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

36 / 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

37 / 50

Curve III in the bellow diagram represents a/an_________?

Pseudo plastic fluid

None of these

Dilatent fluid

Ideal plastic

38 / 50

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

None of these

Back flow through impeller

Loss of kinetic head

Loss of static head

39 / 50

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

d4/5

d1/3

d2/3

40 / 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

41 / 50

Cp/Cv is termed as___________?

Mach number

Adiabatic constant

Weber number

Prandtl number

42 / 50

Centrifugal pump can?t be used to pump _______?

Thick molten soap at 80?C

None of the above

Moderately viscous vegetable oil used in soap industry

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

43 / 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

Decrease in effect

Increase in thrust

Develops high pressure

44 / 50

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

Keep the pipe in proper orientation

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

Make the pipe joint leak-proof

Account for the pressure variation side the pipeline

45 / 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

46 / 50

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

Is at the centroid of the plane surface

Is independent of the specific weight of the fluid

Is different for different fluids

Lies above the centroid of the plane surface

47 / 50

Buoyant force___________?

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

None of these

48 / 50

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

F-2. L

F.L-2

F-1. L

FL-1

49 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head = developed head

50 / 50

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

Stoke?s law

Hagen-Poiseuille?s equation

None of these

Navier-stokes equation

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