Chemical Engineering Fluid Mechanics & Fluid Kinematics Questions - Set 23 - ObjectiveBooks

# Practice Test: Question Set - 23

1. 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
(A) 0.42
(B) 0.62
(C) 0.82
(D) 0.98

2. Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate.
(A) Elastic
(B) Viscous
(C) Gravity
(D) None of these

3. The head loss in turbulent flow in a pipe varies
(A) As velocity
(B) As (velocity)2
(C) Inversely as the square of diameter
(D) Inversely as the velocity

4. Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.)
(A) √d
(B) d2/3
(C) d4/5
(D) d1/3

5. The fluid property, due to which, mercury does not wet the glass is
(A) Surface tension
(B) Viscosity
(C) Cohesion

6. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the
(A) Discharge
(B) Suction
(C) Suction minus vapor pressure of the liquid at suction temperature
(D) Discharge minus vapor pressure of the liquid at the discharge temperature

7. The ratio of inertial forces to elastic forces is called the __________ number.
(A) Reynolds
(B) Mach
(C) Euler
(D) Weber

8. Select the correct statement.
(A) The discharge through a Venturimeter depends upon Δp only and is independent of orientation of the meter
(B) A Venturimeter with a given gage difference discharges at a greater rate, when the flow is vertically downward through it, than when the flow is vertically upward
(C) For a given pressure difference, the discharge of gas is greater through a Venturimeter, when compressibility is taken into account, than when it is neglected
(D) The overall pressure loss is the same in a given pipe line, whether a Venturimeter or a nozzle with the same throat dia is used

9. Centrifugal compressors compared to reciprocating compressors
(A) Require less space
(B) Have quieter operation
(C) Have lower operating costs
(D) All (a), (b) and (c)

10. Nominal size of the discharge pipe of a pump is usually __________ the nominal size of the inlet pipe.
(A) Smaller than
(B) Larger than
(C) Same as
(D) Twice

11. A fluid element has a velocity V = -y2. xi + 2yx2 . j. The motion at (x, y) = (1/√2, 1) is
(A) Rotational and incompressible
(B) Rotational and compressible
(C) Irrotational and compressible
(D) Irrotational and incompressible

12. Which of the following has the minimum compressibility?
(A) Water at room temperature
(B) Air at room temperature
(C) Oxygen at room temperature
(D) Nitrogen at room temperature

13. A stream tube is that, which has __________ cross-section entirely bounded by stream lines.
(A) A circular
(B) Any convenient
(C) A small
(D) A large

14. Power loss in an orificemeter is __________ that in a Venturimeter.
(A) Less than
(B) Same as
(C) More than
(D) Data insufficient, cannot be predicted

15. Applying a pressure drop across a capillary results in a volumetric flow rate 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is
(A) Q/2
(B) Q/4
(C) Q/8
(D) Q/16

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