In this paper a double-layered microchannel gas-togas heat exchanger has been designed and experimentally investigated. The micro heat exchanger (micro HEX) core is based on 133 parallel microchannels machined into polished PEEK plate for both hot side and cold side. Each microchannel is 200 μm high, 200 μm wide and 39.8 mm long. The microchannel layers have been designed in order to be able to test the effect on the thermal performances of the micro heat exchanger of partition foils made in different materials and of various thicknesses. In addition, the device allows to test the layers under three different flow arrangements, namely, countercurrent flow, cocurrent flow and cross flow. Customized pressure and temperature sensors are integrated into the microHEX to enable in-situ measurements. Experimental tests have been performed for various mass flow rates of hot and cold currents. The experimental results are compared with the predictions of the classical theory for conventionally sized heat exchangers. The influence of flow arrangements and wall axial conduction on the thermal performance of the micro heat exchanger are analyzed by considering both the theory and the experimental results.
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