The comparison of longitudinal wall conduction effect on the crossflow heat exchangers including three fluid streams with different arrangements

This study investigates the effect of longitudinal wall conduction on a crossflow heat exchanger including three fluid streams with three different arrangements. By using numerical method, this study calculates the exit mean temperature of each fluid stream and then computes the deterioration factor of each fluid stream in each arrangement. The results indicate that the effect of longitudinal wall conduction for fluid stream 3 in first arrangement is more severe than that in second arrangement when the heat capacity rate ratio of fluid stream 1 is same to that of fluid stream 3. The deterioration factor of fluid stream 2 is affected slightly by the change of inlet temperature of fluid stream 3 in first and second arrangements. Besides, the longitudinal wall conduction strongly deteriorates the thermal performance of heat exchangers including three fluid streams at lower heat capacity rate ratios.