The combined effects of wall longitudinal heat conduction, inlet fluid flow nonuniformity and temperature nonuniformity in compact tube-fin heat exchangers: a finite element method

A finite element analysis of a crossflow tube-fin compact heat exchanger is presented. The analysis takes into account the combined effects of one-dim ensional longitudinal heat conduction through the exchanger wall and nonuni form inlet fluid flow and temperature distributions on both hot and cold fl uid sides. A mathematical equation is developed to generate different types of fluid flow/temperature maldistribution models considering the possible deviations in fluid flow. Using these fluid flow/temperature maldistributio n models, the exchanger effectiveness and its deterioration due to the comb ined effects of longitudinal heat conduction and flow/temperature nonunifor mity are calculated for various design and operating conditions of the exch anger. It was found that the performance deteriorations are quite significa nt in some typical applications due to the combined effects of longitudinal heat conduction: temperature nonuniformity and fluid flow nonuniformity on crossflow tube-fin heat exchanger. (C) 1998 Elsevier Science Ltd. All righ ts reserved.