ABSTRACT
This chapter reviews several important analogy theories for heat and momentum transport. It argues that the empirical correlations for friction factor, heat transfer coefficient, and mass transfer coefficient represent empirical solutions to the momentum, energy, and mass species conservation equations. The usefulness of the analogy approach becomes clear by noting that measurement of friction factor is usually much simpler than the measurement of heat or mass transfer coefficients. Most analogy theories thus attempt to derive relations in the generic forms which represent analogy between heat and momentum transfer. The chapter considers the two-dimensional boundary layer on a flat surface that is subject to a steady and parallel flow of an incompressible constant-property fluid. It discusses the turbulence model of Churchill for fully developed turbulent flow in circular channels.
