Chapter 5 - Rate of Generation in Momentum, Energy and Mass Transfer

Abstract

This chapter derives the explicit expressions for the generation rate per unit volume (R) for the cases of momentum, energy, and mass transport. In the rate of generation of momentum transport, for a given system the inventory rate equation for momentum can be expressed in terms of the forces acting on a system. These forces include: the pressure force (surface force), and the gravitational force (body force). The chapter focuses on the issue of “rate of generation in energy transport,” and explains the paradox called: “One of the most important problems that the world faces today is energy shortage.” According to the first law of thermodynamics, energy is converted from one form to another and transferred from one system to another but its total is conserved. If energy is conserved, then there should be no energy shortage”. Rate of generation in mass transport are described with the inclusion of Stoichiometry of a chemical reaction, the law of combining proportions, and rate of reaction. In the law of combining proportions, the molar extent of the reaction is an extensive property measured in moles and its value can be greater than unity. The rate constant can be determined by running the same reaction at different temperatures and using the Arrhenius relation.