NUMERICAL-SOLUTION OF THE CONJUGATE HEAT-TRANSFER BETWEEN FORCED COUNTERFLOWING STREAMS

In this paper we study numerically the steady-state conjugate heat transfer process between two counterflowing forced streams separated by a wall with finite thermal conductivity. Using the Lighthill approximation, the energy equations for both fluids can be written as an integral relationship between the temperature and the temperature gradient at both interfaces. The energy equation for the solid given by the Laplace equation is solved numerically using the above mentioned boundary conditions together with those coming from the adiabatic edges. Three non-dimensional parameters appear in the problem, alpha, beta and epsilon. alpha corresponds to the ratio of the ability of the plate to carry heat in the streamwise direction to the ability of the fluid to carry out of the plate, beta ist the relationship between the thermal boundary layer thicknesses of both fluids and epsilon corresponds to the aspect ratio of the plate. The distribution of the temperature of the plate as well the overall heat transfer rates have been numerically obtained. The influence of the longitudinal heat conduction through the wall is very important on the overall heat transfer rates. The maximum average Nusselt number occurs for a finite value of alpha, depending strongly on beta and epsilon