THE CHARACTERISTICS OF LOCAL MECHANICAL ENERGY DISSIPATION IN THE FIN SIDE OF A CIRCULAR TUBE BANK FIN HEAT EXCHANGER

摘要

The mechanical energy dissipation characteristics in the fin side channel of a circular tube bank fin heat exchanger and their relations with the convective heat transfer characteristics on the fin surfaces are studied numerically. Most mechanical energy is dissipated in the regions near the surface and beside the tubes （having an arc angle from 0°to 138° relating to the upstream direction). In these regions the local heat transfer coefficient is large. The distribution of the span-volume-average mechanical energy dissipation has a trend roughly similar to the distribution of the span-average heat transfer coefficient. Downstream the mechanical energy dissipation has less efficiency to enhance heat transfer. The dimensionless span-volume-average mechanical energy dissipation φrms and span-average Euler Number Eurms do not closely correspond. The change of Eurms reflects that the static pressure energy may change into mechanical energy.