Heat Transfer

The generation, utilization, conversion, and exchange of thermal energy (heat) across physical systems is the subject of the thermal engineering field known as heat transfer. Different heat transmission techniques, including thermal conduction, thermal convection, thermal radiation, and energy transfer by phase changes, are categorized. To achieve heat transmission, engineers also take into account the advection of material containing various chemical species, whether hot or cold. Despite the fact that each of these processes has unique properties, they frequently coexist in the same system.

Heat conduction, also known as diffusion, is the microscopic exchange of kinetic energy via the border of two systems between particles (like molecules) or quasiparticles (like lattice waves). When a body or its surroundings are at a temperature that is different from an object, heat flows between them until they both reach the same temperature, at which point they are in thermal equilibrium. According to the second rule of thermodynamics, such spontaneous heat transfer always takes place from one area with a high temperature to another with a lower temperature.

When a fluid (gas or liquid) flows in its bulk, its heat is carried through the fluid. This is known as heat convection. Heat is also moved in part through diffusion in all convective processes. The movement of a fluid may be influenced by external forces or, less frequently (in gravitational fields), buoyant forces brought on by the expansion of the fluid due to heat energy (such as in a fire plume). The latter is frequently referred to as "natural convection." The former method is frequently referred to as "forced convection." In this instance, a pump, fan, or other mechanical device is used to compel the fluid to flow.

Thermal radiation occurs through a vacuum or any transparent medium (solid or fluid or gas). It is the transfer of energy by means of photons or electromagnetic waves governed by the same laws.

This course contains important derivations, laws related to various modes of Heat transfer. A total of 8 chapters will be discussed which are as follows

1. Introduction

2. Conduction

3. Fins or Extended Surfaces

4. Transient Heat Conduction

5. Dimensional Analysis

6. Convection

7. Radiation

8. Heat Exchangers

Some important problems will also be discussed. This course will be helpful for the aspirants of GATE/ESE and PSU's