**1. Introduction to modeling and simulation of heat transfer**

"Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy and/or heat between physical systems. Heat transfer is classified into various mechanisms, such as heat con‐ duction, convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system" [1].

In recent times, numerical modeling and simulation techniques have been increasingly applied to the problems of heat transfer. Various studies have been carried out utilizing the basic techniques and their modifications and/or customized variants to customize, operate, test, evaluate, optimize and judge the performance of experimental systems and actual engineering problems. Problems particularly related to engineering issues in the fields of energy [2], oil and gas, metallurgy [3], chemical, process and reaction engineering, fuel cell technologies, manufacturing technologies [2], nanotechnology [4, 5], and aerospace have been extensively studied.

This chapter enlists, describes, explains and elaborates with examples these techniques as applied to problems and practical scenarios of heat transfer.
