EXPERIMENTAL INVESTIGATION OF MICRO HEAT EXCHANGERS USING POROUS MEDIA OR MICROCHANNELS

摘要

The flow and heat transfer performance of a micro-channel heat exchanger and a micro-porous heat exchanger are investigated experimentally and compared with two other heat exchanger designs. The results revealed that the heat transfer performance of the micro-porous heat exchanger is better than that of the micro-channel heat exchanger, but the pressure drop increases correspondingly. For the conditions investigated, the maximum volumetric heat transfer coefficient of the micro-porous heat exchanger is 86.3 MW/(m{sup}3K), the corresponding mass flow rate is 0.067 kg/s and the pressure drop is 4.66 bar. The maximum volumetric heat transfer coefficient of the micro-channel heat exchanger is 38.4 MW/(m{sup}3K), the corresponding mass flow rate is 0.34 kg/s and the pressure drop is 0.9 bar. The overall performance considering both the heat transfer and pressure drop of the micro heat exchanger using deeper microchannels is better than the micro heat exchangers using shallow microchannels or porous media.