微小通道氢—氦换热器传热分析与结构改进

Heat Transfer Analysis and Structure Improvement of Micro-channel Hydrogen/Helium Heat Exchanger

微小通道氢-氦换热器在高超声速飞行器中具有潜在的应用前景,研究其流动传热特性并对换热器进行结构参数的优化具有重要的意义。本文数值模拟结果表明,减小通道间壁厚度和深宽比有助于提升换热器的传热性能,减小肋宽、间壁厚度和采用方形通道有助于提升换热器的功率密度。提出了一种能够降低换热器固体结构热阻的交错通道布置方式,但由于氢-氦换热器的换热热阻主要集中在流体侧,因此传热优化效果较弱,但用于流体侧热阻较小或固体材料热导率较低的换热器时有明显的改善传热效果。

The micro-channel heat exchanger(MHX) for hydrogen and helium possesses potential application in hypersonic vehicles. It is of great significance to study the flow and heat transfer characteristics and optimize the structure for this MHX. The numerical simulations of this article on the flow and heat transfer characteristic of hydrogen/helium MHX indicate that reducing the thickness of channel partition wall and the aspect ratio could improve the thermal performance of the MHX, and reducing the rib width, the partition wall thickness and adopting square channels are helpful to improve the power density. A staggered channel arrangement for MHX is proposed,which could reduce the thermal resistance of solid structure. Due to the heat transfer resistance of hydrogen/helium MHX mainly concentrates on the fluid side, the improvement on heat transfer is weak, while this staggered channel arrangement can improve the heat transfer obviously for MHX with low resistance at fluid side or low solid thermal conductivity.