Heat Transfer Basic Mechanical Engineering & Nano Science JANGAM SASIDHAR
Index ❑ Heat Transfer – Definition & Basics ❑ Modes / Mechanisms of Heat transfer ❑ Conduction ❑ Convection ❑ Radiation ❑ Heat Transfer & its governing equations ❑ Fins – Types & Applications ❑ Heat Exchangers – working principle & Types
Heat Transfer - Overview ❑ Heat is the form of energy that can be transferred from one system to another as a result of temperature difference, The science that deals with the determination of the rates of such energy transfers is Heat Transfer. ❑ thermodynamics is concerned with the amount of heat transfer as a system undergoes a process from one equilibrium state to another, and it gives no indication about how long the process will take. ❑ In practice we are more concerned about the rate of heat transfer (heat transfer per unit time) than we are with the amount of it. Example, we can determine the amount of heat transferred from a thermos bottle as the hot coffee inside cools from 90°C to 80°C by a thermodynamic analysis alone. But a typical user or designer of a thermos bottle is primarily interested in how long it will be before the hot coffee inside cools to 80°C, and a thermodynamic analysis cannot answer this question
Heat Transfer - Overview ❑ Thermodynamics deals with equilibrium states and changes from one equilibrium state to another. Heat transfer, on the other hand, deals with systems that lack thermal equilibrium, and thus it is a nonequilibrium phenomenon. ❑ Therefore, the study of heat transfer cannot be based on the principles of thermodynamics alone. However, the laws of thermodynamics lay the framework for the science of heat transfer. In practice we are more concerned about the rate of heat transfer (heat transfer per unit time) than we are with the amount of it.