Mass, Momentum and Energy Conservation Equations

Abstract

Heat can be transferred by means of the following three fundamental processes:

• conduction,

• convection,

• radiation.

In practice, these three kinds of the heat transfer co-occur. Heat conduction plays the most significant role in solid bodies, whereas in gases and liquids convection and radiation prevail. Radiation differs from conduction and convection in that it can also occur in a vacuum. Like thermodynamics, the heat transfer phenomenon is based on mass, momentum, and energy conservation equations. The first law of thermodynamics is the law of energy conservation or, simply speaking, the energy balance equation.