# THERMAL ENGINEERING INTERVIEW QUESTION

## THERMAL ENGINEERING INTERVIEW QUESTION

1. What is the importance of the Thermodynamics in the field of Mechanical Engineering?

Ans. All the mechanical engineering systems are studied with the help of thermodynamics. Hence it is very important for the mechanical engineers.

2. How many Laws of Thermodynamics are there?

There are three laws of the thermodynamics.

First Law: Energy can be neither created nor destroyed. It can only change forms.In any process in an isolated system, the total energy remains the same.

Second Law: When two isolated systems in separate but nearby regions of space, each in thermodynamic equilibrium in itself, but not in equilibrium with each other at first, are at some time allowed to interact, breaking the isolation that separates the two systems, and they exchange matter or energy, they will eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initial, isolated systems is less than or equal to the entropy of the final exchanging systems. In the process of reaching a new thermodynamic equilibrium, entropy has increased, or at least has not decreased.

Third Law: As temperature approaches absolute zero, the entropy of a system approaches a minimum.

THERMAL ENGINEERING INTERVIEW QUESTION 2023

3. How do you want to contribute to the field of thermal engineering in the future?

Alongside your professional expertise, employers may explore your personal philosophy or goals in the field of thermal engineering to see if they align with company objectives or values.

answer: I plan to continue to position myself as an expert in my field by continuously updating my skill set and expertise through webinars, networking and education. Additionally, I hope to find employment at a company that values advancement and innovation in thermal engineering, so I can be part of the industry’s growth. I plan to work hard on developing new, more efficient and effective thermal management systems and collaborate with the industry’s top minds whenever possible.

## THERMAL ENGINEERING

4. Define engineering thermodynamics?

Ans. It is the science which analyses the problems related to the conversion of heat to work and vice-versa and changes in properties of the working fluids involved in such a conversion.

The thermodynamic study deals with a concept of ideal processes and most possible efficient operation of machine. This science establishes the fact that to what extent a particular process provides efficiency to the ideal conditions.

The study analyses thermal system and properties of the system and establishes a relationship between the various properties and parameter involved in system. It may be possible to know maximum work and efficiency of the system.

### THERMAL ENGINEERING INTERVIEW QUESTION

5. What are the areas of thermal engineering?

Ans. There are various areas of thermal engineering which are based on the study of engineering thermo-dynamics. The Engineering thermodynamics considers various thermal processes ideally possible and results of these processes are hypothetical, which are results to indicate scientifically how conversion processes are possible.

The thermal engineering is divided into various areas like:

(1) Heat Engines:

These are the devices in which heat energy is converted into mechanical energy by performing series of thermodynamic processes. The heat engines convert heat energy into useful mechanical work.

These are various types of heat engines such as:

(1) Steam engine

(2) Steam turbine

(3) I.C. engine, and

(4) Gas turbines.

(2) Energy Sources:

These are various sources of energy.

They are divided into two categories:

(1) Conventional energy source

(2) Unconventional energy sources.

The conventional energy sources are fuels such as solid, liquid and gaseous fuels. The hydraulic energy is conventional energy.

The unconventional energy sources are:

(1) Solar energy

(2) Wind energy

(3) Tidal energy

(4) MHD

(3) Refrigeration and Air-Conditioning:

These low temperature applications in which the system is brought to the temperature below atmospheric temperature. The system where the temperature is brought below the normal temperature.

The systems are known as:

(1) Refrigeration system

(2) Air-conditioning system.

In the refrigeration system, the temperature is brought below 0°C and article, foods, items, medices etc. can be maintained below atmospheric temperature.

In the air-conditioning system, the temperature of system brought to human comfort level and maintaining the system with proper humidity, odour etc. The system conditioned to human acceptable level.

(4) Heat and Mass Transfer:

This is study of transfer heat from one place to another.

The heat is transferred from one body to another using various modes like:

(1) Conduction

(2) Convection

The transfer mass due combustion or diffusion or interaction is known mass transfer. The mass can be changing its phase in mass transfer process.

(5) Fuel and Combustion System:

This is area of thermal engineering in which the study of properties and combustion characteristics of various fuels is carried out. The combustion systems and methods are studied and analysed.

(6) Compressor and Blowers:

The compressors are the devices used for compression of air and fluids. The fluid is compressed to high pressure and temperature. This involves suction of fluid and increasing the pressure in return reducing the volume of fluid.

(7) Cryogenic:

This is the science dealing with behaviour of fluids at very low temperatures.

(8) Jet Propulsion:

This is the propulsion of jet resulting into movement object at high attitudes.

also read:- automobile engineering interview questions

6. What Is Meant By Free Or Natural Convection?

Ans. It is fluid movement is produced due to trade in density as a consequence of temperature gradients, the mode of heat transfer is said to be unfastened or natural convection.

7. Define Grashof Number [gr].?

Ans. It is described because the ratio of made from inertia force and buoyancy pressure to the rectangular of viscous pressure.

Gr = Inertia pressure x Buoyancy force / [Viscous force]2

8. Define Stanton Number [st].?

Ans. It is the ratio of Nusselt quantity to the manufactured from Reynolds wide variety andPrandtl range.

. St = Nu / Re x Pr.

9. What Is Meant By Newtonian And Non-newtonian Fluids?

Ans. The fluids which obey the Newton’s law of viscosity are referred to as Newtonian fluids and those which do not obey are called no-newtonian fluids.

10. What Is Meant By Laminar Flow ?

Ans. Laminar glide: Laminar glide is once in a while referred to as stream line flow. In this sort of waft, the fluid moves in layers and every fluid particle follows a clean continuous route. The fluid particles in every layer continue to be in an orderly series with out mixing with each other.

11. Mention Stefan Boltzmann Constant?

Ans. σ = Stefan Boltzmann regular = 5.6697 x 10-eight W/ (m² K4).

12. What Is Meant By Absorptivity?

13. What Is Meant By Direct Heat Exchanger [or] Open Heat Exchanger?

Ans. In direct touch heat exchanger, the heat change takes area via direct mixing of warm and cold fluids.

Good luck guys 👍

Sahil Dahiya is a close follower of tech and everything that has the word 'smart' involved. This makes him passionate to write about everything revolving around the world of technology. He can always be seen surfing the web and while he’s not working, you can find him watching netflix and reading comics.

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