Engineering Questions with Answers - Multiple Choice Questions
Separation Processes MCQ’s – Mass Transfer in Turbulent Flow
1 - Question
Which of the following is true about turbulent flow?
a) Nre greater than 2000
b) Nre greater than 4000
c) Nre greater than 5000
d) Nre greater than 6000
View Answer
Explanation: The flow becomes turbulent for a reynold’s number above 4000.
2 - Question
Which of the following reynold’s number represents a turbulent flow?
a) 500
b) 700
c) 2500
d) 6000
View Answer
Explanation: The flow becomes turbulent for a reynold’s number above 4000.
3 - Question
Which of the following is present in turbulent flow mass transfer?
a) Slow mass transfer
b) Less mass transfer
c) Eddy currents
d) Eddy diffusion
View Answer
Explanation: Eddy diffusion is created due to the turbulent flow because of which mass transfer is fast.
4 - Question
What is the physical significance of drag coefficient?
a) It is drag force divided by projected area and velocity head
b) It is the ratio of pipe wall shear stress and velocity head
c) It is the ratio of inertial forces to viscous force
d) It is the ratio of inertial force to surface tension force
View Answer
Explanation: The drag coefficient Cd=2FD/Au2ρ is drag force divided by projected area and velocity head.
5 - Question
What is the physical significance of weber number?
a) It is drag force divided by projected area and velocity head
b) It is the ratio of pipe wall shear stress and velocity head
c) It is the ratio of inertial forces to viscous force
d) It is the ratio of inertial force to surface tension force
View Answer
Explanation: The weber number is the ratio of inertial force to surface tension force.
6 - Question
What is the physical significance of lewis number?
a) It is the ratio of bulk transfer mass and molecular diffusion
b) It is the ratio of thermal diffusivity to mass diffusivity
c) It is the ratio of conductive mass transfer to molecular diffusion
d) It is the ratio of mass transfer to mass capacity
View Answer
Explanation: Lewis number is the ratio of thermal diffusivity to mass diffusivity.
7 - Question
What is the Sherwood number analogous to?
a) Schmidt number
b) Lewis number
c) Nusselt number
d) Prandtl number
View Answer
Explanation: The Sherwood number Nsh =KcL/Dab is analogous to nusselt number.
8 - Question
Which of the following equations is referred as reynold’s analogy?
a) f/c = kc/ux
b) f/c = kcux
c) f/2 = kcux
d) f/2 = kc/ux
View Answer
Explanation: The equation f/2 = kc/ux is referred to as reynold’s analogy.
9 - Question
For what condition does the equation for reynold’s analogy equals to equation by Chilton-colburn analogy.
a) Npr=Nre=1
b) Npr=Nse=1
c) Npr=Nsc=1
d) Nsc=Nse=1
View Answer
Explanation: For Npr=Nsc=1 the equation for reynold’s analogy equals to equation by Chilton-colburn analogy.
10 - Question
What is the significance of fanning friction factor?
a) It is the ratio of pipe wall shear stress to velocity head
b) It is drag force divided by projected area and velocity head
c) It is the ratio of inertial forces to viscous force
d) It is the ratio of inertial force to surface tension force
View Answer
Explanation: The fanning friction factor is the ratio of pipe wall shear stress to velocity head.