Engineering Questions with Answers - Multiple Choice Questions
MCQs on Flow of Compressible Fluid through Orifices and Nozzles
1 - Question
What is the Mach number at room temperature?
a) 310 m/s
b) 320 m/s
c) 330 m/s
d) 340 m/s
View Answer
d
Explanation: Mach number is defined as the ratio of the speed of an object to the speed of sound. Mach number is denoted by ‘M’. Mach number ranges from zero to infinity. It falls into several flow regimes. It is 340 m/s at room temperature.
2 - Question
In a one-dimensional flow, the gas flows through one spatial dimension, namely its length.
a) True
b) False
View Answer
a
Explanation: One dimensional flow refers to the flow of gas through a duct or channel in which the flow parameters are assumed to change significantly along a particular dimension. In this case, it’s about its duct length.
3 - Question
The compressible flow is assumed to be _____________
a) Isentropic
b) Adiabatic
c) Polytropic
d) Isentropic and adiabatic
View Answer
a
Explanation: Compressible flow is a branch of fluid mechanics that deals with different types of flow. Its main significance lies on the change in fluid density. It deals with gas dynamics. Flow is assumed to be isentropic.
4 - Question
Ratio of duct length to width length in a compressible flow is_______
a) More than 5
b) Less than 5
c) More than or equal to 5
d) Less than or equal to 5
View Answer
d
Explanation: In a compressible flow, the flow is usually in a single dimension. One dimensional flow refers to the flow of gas through a duct or channel in which the flow parameters are assumed to change significantly. Thus, it is less than or equal to 5.
5 - Question
The fluid speed through the nozzle is altered with________
a) Acceleration
b) Deceleration
c) Constant speed
d) Zero
View Answer
a
Explanation: The fluid speed through the nozzle is altered as the speed accelerates from subsonic speed to supersonic speed in a regime. It alters a nozzle and a diffuser.
6 - Question
What happens to velocity in the converging duct?
a) Increases
b) Decreases
c) Same
d) Independent
View Answer
a
Explanation: Mass flow rate is given by Q = m/p. This is a relation expressed for mass flow rate. With the presence of a converging duct, the velocity increases. At this point, the area of the duct is less than zero.
7 - Question
What happens to velocity in the diverging duct?
a) Increases
b) Decreases
c) Same
d) Independent
View Answer
b
Explanation: Mass flow rate is given by Q = m/p. This is a relation expressed for mass flow rate. With the presence of a converging duct, the velocity decreases. At this point, the area of the duct is more than zero.
8 - Question
The area of the duct is either maximum or minimum when the_________
a) Mach number = 1
b) Mach > 1
c) Mach = 0
d) Mach < 0
View Answer
a
Explanation: Mass flow rate is given by Q = m/p. This is a relation expressed for mass flow rate. The area of the duct is either maximum or minimum when the Mach number of the fluid flow is exactly one.
9 - Question
Which among the following is an assumption of the compressible flow?
a) Resistance to flow of object
b) No-slip condition
c) Known mass flow rate
d) Resistance to flow of heat
View Answer
b
Explanation: The related assumption of a compressible fluid flow is No-slip condition. It is assumed that the flow velocity at the solid surface is equal to the velocity of the surface itself. It is in direct consequence of the continuum flow.
10 - Question
Which among the following is an example of a converging-diverging nozzle?
a) De Laval nozzle
b) High velocity nozzle
c) Magnetic nozzle
d) Vacuum nozzle
View Answer
a
Explanation: De-Laval nozzle is an example of a converging diverging nozzle. It a tube that is pinched in the mid marking with a particular balance. It is used to accelerate, hot pressurized gases that pass through a higher supersonic speed in the axial thrust.
11 - Question
Maximum achievable velocity of a gas is directly proportional to__________
a) Specific heat
b) Deceleration
c) Velocity
d) Pressure
View Answer
a
Explanation: Maximum achievable velocity of a gas is directly proportional to the specific heat of gas. It is based on the energy content. It is derived in accordance with the law of conservation of energy.
12 - Question
How much pressure ratio makes one Mach number?
a) 0
b) 1
c) 2
d) 3
View Answer
c
Explanation: The overall pressure ratio is given by Pb/Pt. The overall pressure ratio must be approximately 2 to attain the Mach number of one. It is because of the changes in the downstream and upstream of flow in the nozzle.
13 - Question
Normal shock waves are_______ to the local flow.
a) Parallel
b) Perpendicular
c) Same
d) Independent
View Answer
b
Explanation: Normal shock waves are perpendicular to the local flow direction. The shock waves occur when the pressure builds up into an extremely thin shockwave that converts energy into heat. The waves thus take over one another.
14 - Question
Oblique shock waves are ______ to the local flow.
a) Parallel
b) Perpendicular
c) Less than 90 degrees
d) Independent
View Answer
a
Explanation: Oblique shock waves have an angle less than 90 degrees with respect to its local flow. They are similar to the normal shock waves. When there is any disturbance to the fluid flow at a non-zero angle oblique shock is formed.