Effect of Flow Arrangement on the Heat Transfer Behaviors of a Microchannel Heat Exchanger

摘要

A study on the effect of flow arrangement was carried out for the heat transfer behaviors of a microchannel heat exchanger The results were obtained by both numerical simulations and experimental data The solver of numerical simulations - COMSOL - was developed by using the finite element method. For all cases done in this study, the heat flux obtained from the counter-flow arrangement is always higher than that obtained from the parallel-flow one: the value obtained from the counter-flow is 1.1 to 1.2 times of that obtained from the parallel-flow. This means that the heat transfer behaviors of the microchanel heat exchanger with counter-flow are better than those with parallel-flow. For the case of the counter-flow, the experimental results indicated that the total heat flux of 17.81 W/cm~2 was achieved for water from the hot side of the device having the inlet temperature of 70°C and flow rate of 0.2321 g/s and for water from the cold side having the inlet temperature of 22.5°C and flow rate of 0.401 g/s. In addition, the results obtained from the numerical analyses were in good agreement with those obtained from the experiments, with the discrepancies of the heat transfer coefficient estimated to be less than 10%.