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Some Significant Mechanical Engineering Questions for Students

Updated on December 31, 2016

Mechanical Engineering is one of the oldest disciplines in the engineering studies. It is vast and core engineering subject. If the topics of this great subject are well organized and simplified then the students will not face hard time completing their courses. From many days I was thinking of publishing some useful mechanical engineering contents in the form of questions & answers. As a mechanical engineer I have tried to to gather some theoretical questions which will be helpful for the graduation as well as job interview questions. Okay lets begin .

Mechanical Engineering Interview Questions

In this section I will discuss questions about Heat Transfer, Thermodynamics, Refrigeration & Air Conditioning, Solid Mechanics , Fluid Mechanics , Power Plant Engineering , IC engines etc.

  • What is the difference between machine & Engine ?

Answer : Heat engine only converts heat energy to mechanical energy whereas machine converts all types of energy to mechanical energy - except heat energy.

  • What are significant heat engine cycles used in modern automobile and power generation methods ?

Answer: Otto Cycle, Diesel Cycle, Stirling Cycle, Joul/ Brayton Cycle, Ericsson Cycle, Ranking Cycle.

  • Which thermodynamic cycle is used in Coal fired Power Plant ?

Answer: Rankin Cycle .

  • Draw the p-v and T-s Diagram of Rankin Cycle .

Answer:

p-v and t-s diagram of the Rankin Cycle

T-s diagram of the Rankin Cycle
T-s diagram of the Rankin Cycle
p-v diagram of rankin cycle
p-v diagram of rankin cycle
  • Show the differences between vapor compression and vapor absorption refrigeration cycle .

Answer:

Vapor Compression
Vapor Absorption
Vapor Compression Refrigeration System Needs High Quality Energy Sources. For example high quality energy is needed to run the compressor
Vapor Absorption refrigeration system can run with loq quality waste heats and exhaust steam etc.
V.C system has moving parts in compressor
Vapor absorption system has moving parts in pumps
It doesn't work well on partial load conditions
It runs on different load condition . Performance in different conditions is similar
COP is high
COP is poor in comparison to V.C
  • Which Cycle is used to run Gas Turbine ?

Answer : Brayton Cycle is used to run the Gas turbine. Gas Turbine Cycle can used with Reheating, Regeneration and also intercooling.

  • Give examples of Internal combustion and External Combustion Engine.

Answer : I.C Engines - Diesel engine, Gas turbine cycle, Otto cycle etc.

External Combustion Engine : Steam Turbine.

  • What is Reynolds Number ?

Answer : It is the ratio of inertia force to the viscous force.

  • How to determine if a fluid flow is laminar or turbulent ?

Answer: If Reynolds number is less that 2300 then the flow is laminar and if the Reynolds number is greater than 4000, the flow is turbulent. The flow having a value in between them is known as the transient flow.

  • What is the difference between pump and turbine ?

Answer: The pump is a device which converts mechanical energy to flow energy. Turbine is a device which converts flow energy to mechanical energy and thus mechanical energy is then converted to electrical energy.

  • What is the difference between Positive Displacement and Centrifugal or non positive displacement pump ?

Answer: In positive displacement pump the flow rate remains constant but in centrifugal pump the flow rate is not constant.

  • What is LMTD method ?

Answer: LMTD is the Logarithmic Mean Temperature Difference method which used to measure the heat transfer rate in double pipe heat exchangers.

Mecha Quiz 1


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  • What is the difference between Beam and column ?

Answer: Beam is a member which carries load perpendicular to its geometrical axis and also deals with bending moment. It is generally a horizontal member.

Column is a member which carries compressive load . This is generally a vertical member.

  • What are the different types of beams ?

Answer: Simple beam or simple supported beam, overhanging beam , cantilever beam, Continuous beam etc.

  • What is system in Thermodynamics ?

Answer: System is a Space in Which a Thermodynamics process takes place.

  • What is surrounding in Thermodynamics ?

Answer: Surrounding is the space outside the real or imaginary boundary of a thermodynamics system.

  • What is entropy in Thermodynamics ?

Answer: Entropy is the measure of microscopic disorder in a system/ substance.

  • What are the different Heat Transfer Methods ?

Answer : Conduction, Convection and Radiation.

Thanks Mecha people . Its is a start of mechanical engineering interview question collection. Some more articles will be published soon Stay Tuned.

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