CONJUGATE HEAT TRANSFER ANALYSIS OF A RECTANGULAR COOLING CHANNEL WITH 45-DEG RIBS

摘要

A conjugate heat transfer simulation of air in a rectangular cooling channel with 45-deg ribs is presented in this paper. The test channel length is 400mm and the ratio of width to height is 1. The hydraulic diameter of the channel is 40mm and the thickness of channel wall is 3mm. The rib height is 1.9mm and the distance between nearby ribs is 19mm. The flow field and the temperature field in the solid channel are obtained by using ANSYS CFX. An energy source is added in the solid domain to simulate the Low-Voltage High-Current heating method in the experiment. The GGI method is adopted for the mesh connection between the fluid domain and solid domain. The SST turbulence model and automatic wall function in ANSYS CFX are used to simulate the flow and heat transfer in near-wall region. The numerical results show great agreement with the experimental data. The temperature distribution on the channel outer wall is shown and analyzed. The Nusselt number field on the channel wall is shown and illustrated by the flow field shown by the Vortex Core Technology. There are four secondary flow vortex cores between ribs in near wall region and a strong secondary flow can be seen in main flow region. The angled ribs leads to the unbalanced temperature and Nusselt number field on the outer wall and the inner wall of the channel respectively. The distribution law of the Nusselt number on inner wall is not similar with the one of temperature on the outer wall. But the overall distribution of outer wall temperature field is more homogeneous compared with that of the inner wall Nusselt number. Some recommendations for optimization are given based on the flow field and Nusselt number distribution.