STEADY-STATE ANALYSIS OF THE CONJUGATE HEAT-TRANSFER BETWEEN FORCED COUNTERFLOWING STREAMS

In this article we analyze the steady-state conjugate heat transfer pr ocess between two counterflowing forced streams separated by a wall wi th finite thermal conductivity, The influence of the longitudinal heat conduction through the wall is very important on the overall heat tra nsfer rates and has been analytically deduced, The most important para meters are denoted by alpha, beta, and epsilon. The parameter alpha co rresponds to the ratio of the solid heat conduction in the longitudina l direction to the convected heat towards the hotter fluid, beta is th e relationship between the thermal boundary-layer thickness of both fl uids, and epsilon is the aspect ratio of the plate. In the asymptotic limit alpha --> infinity and using the Lighthill approximation, it can be shown that the balance equations reduce to a single integro-differ ential equation with only the parameters alpha and beta. This limit is analyzed using regular perturbation techniques, On the other hand, fo r alpha --> 0, the governing equations can also be solved using asympt otic methods. The distribution of the temperature of the plate as well as the overall heat transfer rates have been obtained in closed form and compared with the numerical solution for different values of the p arametric set, In general, close to the analyzed limits, a good agreem ent is achieved.