51
The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the
A)
Static submergence
B)
Net positive suction head (NPSH)
C)
Cavitation sensitivity
D)
Priming
Answer & Solution
Answer: Option
B
52
The vent valve provided in a liquid handling centrifugal pump is
A)
Generally a needle valve
B)
Used to release any gases that might be vapour locking the pump
C)
Helpful in easy removal of samples
D)
All of the above
Answer & Solution
Answer: Option
D
53
Stoke's equation is valid in the Reynolds number range
A)
0.01 to 0.1
B)
0.1 to 2
C)
2 to 10
D)
10 to 100
Answer & Solution
Answer: Option
A
54
A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is __________ litres.
A)
600
B)
660
C)
1.1
D)
60
Answer & Solution
Answer: Option
B
55
In case of turbulent flow of fluid through a circular pipe, the
A)
Mean flow velocity is about 0.5 times the maximum velocity
B)
Velocity profile becomes flatter and flatter with increasing Reynolds number
C)
Point of maximum instability exists at a distance of $$\frac{{2{\text{r}}}}{3}$$ from the pipe wall (r = pipe radius)
D)
Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more
Answer & Solution
Answer: Option
D
56
In case of laminar flow of fluid through a circular pipe, the
A)
Shear stress over the cross-section is proportional to the distance from the surface of the pipe
B)
Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder
C)
Velocity profile varies hyperbolically and the shear stress remains constant over the cross-section
D)
Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)
Answer & Solution
Answer: Option
B
57
Centrifugal compressors compared to reciprocating compressors
A)
Require less space
B)
Have quieter operation
C)
Have lower operating costs
D)
All of the above
Answer & Solution
Answer: Option
D
58
For flow of fluids through packed bed, the superficial velocity is
A)
Less than the average velocity through channels
B)
More than the average velocity through channels
C)
Dependent on the pressure drop across the bed
D)
Same as the average velocity through channels
Answer & Solution
Answer: Option
A
59
Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will
A)
Increase
B)
Decrease
C)
Remain same
D)
Be quadrupled
Answer & Solution
Answer: Option
A
60
Buckingham-π theorem states that in any physical problem including 'n' quantities having 'm' diamensions, the quantities can be arranged into __________ independent dimensionless parameters.
A)
m
B)
n
C)
n - m
D)
$$\frac{{\text{n}}}{{\text{m}}}$$
Answer & Solution
Answer: Option
C
