Study of the parameters affecting conjugated heat transfer in plate-fin and tube heat exchanger

A numerical method was used to study the effect of conduction through the f ins and convection over the fins of a single-row plate-fin and tube heat ex changer. The simulations were conducted for conditions that are equivalent to those encountered in real heat exchangers. The influence of several para meters on conjugate heat transfer was analyzed. The fin surface is divided in two regions: one of high heat transfer in the region upstream of the tub es, and one of low heat transfer located downstream of the tubes. The regio n upstream of the tubes is the most affected by conduction through the fins , with decrease of temperature arid heat transfer when conduction is consid erable. It was also possible to identify a region of heat transfer reversal in the region downstream of the tubes. The parameters found to affect conjugate heat transfer were fin conductivit y and thickness, Reynolds number and tube eccentricity There is a possibili ty of heat transfer augmentation by making the tube eccentric respect to fi n length. By moving the tube nearer to the trailing edge of the fin, the ar ea of low heat transfer downstream of the tube is reduced in size and, at t he same tune, the area upstream of the tubes is increased, with reduced hea t transfer: This suggests the existence of an optimum position of the tube with respect to the fin length.