采用烧结Ni微纤多孔结构材料的微型换热器及其性能

Micro Heat Exchanger with a Novel Sintered Ni Microfibrous Structured Wick and Its Performance

采用烧结Ni微纤多孔结构材料(简称Ni微纤)制备了微型换热器,对其传热和流动性能进行了研究,考察了微型换热器结构对传热系数及流动阻力的影响。实验结果表明,填充Ni微纤能显著强化微型换热器的传热性能,比相同条件下空流道微型换热器的体积传热系数提高了2倍多;降低Ni微纤的孔隙率和减小流道深度可显著提高微型换热器的传热性能,但导致换热器的压降增加;采用导热系数高和厚度小的紫铜换热片有利于提高微型换热器的传热性能。Ni微纤孔隙率为95.1%、流道深度为0.3mm、换热紫铜片厚度为0.1mm、水的体积流量为14.6L/h时,微型换热器的体积传热系数高达40.0MW/(m3.K),面积传热系数可达20kW/(m2.K),压降约为0.2MPa。

A high -performance micro heat exchanger has been constructed by using a novel micro fibrous structured wick. Influence of micro heat exchanger structure parameters on heat transfer coefficient and pressure drop was presented. Heat transfer performance of micro heat exchanger could be enhanced dramatically by using a monolithic micro fibrous structure consisting of nickel fiber 8 μm in diameter. The use of this approach provided 2 - fold or more increase in volumetric heat transfer coefficient under same operational conditions. Reduction of microfibrous structure porosity and flow channel depth promoted heat transfer performance but caused large pressure drop. Moreover, use of thinner heat transfer plate made of copper with higher thermal conductivity coefficient also provided significant promotion of heat transfer performance at high flow rate. Under optimal structure of micro heat exchanger as micro fibrous porosity 95.1%, flow channel depth of 0. 3 mm, copper heat exchange plate thickness of 0. 1 mm and water volume flow rate of 14.6 L/h, volumetric heat transfer coefficient, overall heat transfer coefficient and pressure drop can be 40. 0 MW/（ m^3·K）, 20 kW/ （m^2·K） and 0. 2 MPa, respectively.