Thermodynamics Questions and Answers – Examples of Steady Flow Processes

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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Examples of Steady Flow Processes”.

1. What does a nozzle do?
a) decreases the velocity of a fluid at the cost of its pressure gain
b) increases the velocity of a fluid at the cost of its pressure drop
c) increases the velocity of a fluid and also its pressure
d) none of the mentioned.
View Answer

Answer: b
Explanation: A nozzle increases KE of fluid and reduces its pressure.
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2. What does a diffuser do?
a) increases the pressure of the fluid at the expense of its KE
b) decreases the pressure of the fluid and also increases its KE
c) increases the pressure of the fluid and also its KE
d) decreases the pressure of the fluid and also its KE
View Answer

Answer: a
Explanation: A diffuser increases the pressure at the expense of its KE.

3. For an insulated nozzle, SFEE of the control surface gives ( considering change in PE is zero and inlet velocity is small compared to exit velocity)
a) V2=sqrt(4*Δh)
b) V2=sqrt(Δh)
c) V2=sqrt(Δh/2)
d) V2=sqrt(2*Δh)
View Answer

Answer: d
Explanation: dQ/dm=0, dW/dm=0, Δh=h1-h2.
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4. Fluid flow through which of the following throttles the flow?
a) partially opened valve
b) orifice
c) porous plug
d) all of the mentioned
View Answer

Answer: d
Explanation: In all of the given cases, there is an appreciable drop in pressure and hence the flow is throttled.

5. In a throttling device, what do we get as SFEE when changes in PE and KE are taken zero?
a) dQ/dm≠0
b) dW/dm≠0
c) h1=h2
d) none of the mentioned
View Answer

Answer: c
Explanation: Enthalpy of the fluid before throttling is equal to the enthalpy of the fluid after throttling.
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6. Turbines and engines ____ positive power output, and compressors and pumps ____ power input.
a) require, give
b) give, require
c) give, give
d) require, require
View Answer

Answer: b
Explanation: This is the basic information about turbines, engines, compressors and pumps.

7. For a turbine, it is seen that work is done by the fluid at the expense of its enthalpy.
a) true
b) false
View Answer

Answer: a
Explanation: For a turbine, W/m=h1-h2.
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8. For an adiabatic compressor or pump,
a) the enthalpy of fluid remains constant with the amount of work input
b) the enthalpy of fluid decreases by the amount of work input
c) the enthalpy of fluid increases by the amount of work input
d) none of the mentioned
View Answer

Answer: c
Explanation: For an adiabatic pump or compressor, W/m=h2-h1.

9. A heat exchanger is a device in which heat is transferred from one fluid to another.
a) true
b) false
View Answer

Answer: a
Explanation: Basic fact about heat exchanger.
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10. For an inviscid frictionless fluid flowing through a pipe, Euler equation is given by
a) Vdp+VdV+gdZ=0
b) Vdp-VdV+gdZ=0
c) Vdp-VdV-gdZ=0
d) none of the mentioned
View Answer

Answer: a
Explanation: Euler equation is derived from steady flow energy equation.

11. The Bernoulli equation is restricted to _____ fluids but the SFEE is valid for _____ fluids as well.
a) viscous compressible, frictionless incompressible
b) frictionless incompressible, viscous compressible
c) viscous incompressible, frictionless compressible
d) none of the mentioned
View Answer

Answer: b
Explanation: This statement tells us that the Bernoulli equation is a limiting case of SFEE.

Sanfoundry Global Education & Learning Series – Thermodynamics.
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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter