Multistream Countercurrent Heat Exchangers

Abstract

An idealized model multistream countercurrent exchanger is considered. It comprises a number of parallel two-dimensional streams in channels separated by thin conductive partitions. The streams on the two sides of any partition flow in opposite directions. Thus the heat contained in one set of co-directional currents, which enters the exchanger at a high temperature, is transferred through the partitions to the oppositely directed cooling streams. The analysis accounts for the entire temperature distribution in this model when the axial conduction in the streams and in the partitions is neglected. The solution is obtained by expressing the temperature field in terms of the inlet conditions and the flux across the partitions. The latter is represented by as many a priori unknown functions of the axial distance as there are partitions. They are governed by the same number of linear integral equations. Using a finite-difference technique, these are solved for a variety of cases that are of practical interest.