Thermal-Hydraulic Performance Optimization of Micro-Channel Separate Heat Pipes: A Structural Parameter Study

本文以微通道换热器作为分离式热管的蒸发端和冷凝段，制冷剂选用R22，建立了分离式热管的一维稳态模型，利用MATLAB软件编程模拟计算。经验证实验和模拟的性能参数最大相对误差为9.7%。构建稳态模型研究微通道分离式热管变结构参数下的系统性能，得出结论：1) 扁管高度由1.6 mm增至4.4 mm时，蒸发器制冷剂侧压降急剧降低后趋于平缓，但换热效率随高度增大逐渐劣化；2) 系统换热量随翅片高度增加显著提升，而空气侧压降则呈相反趋势；3) 百叶窗间距与角度对换热性能影响显著，较小间距(This study employs a micro-channel heat exchanger as the evaporator and condenser of a separate heat pipe system using R22 refrigerant. A one-dimensional steady-state model of the separate heat pipe was established and simulated by MATLAB Experimental validation showed a maximum relative error of 9.7% between simulated and measured performance parameters. The steady-state model was utilized to investigate system performance under varying structural parameters of the microchannel separate heat pipe, yielding the following conclusions: 1) As flat tube height increases from 1.6 mm to 4.4 mm, the evaporator refrigerant-side pressure drop decreases sharply before stabilizing, while heat transfer efficiency gradually deteriorates with increasing height; 2) System heat transfer capacity significantly improves with fin height enhancement, whereas air-side pressure drop exhibits an opposite trend; 3) Louver spacing and angle substantially influence heat transfer performance—smaller spacing (<1 mm) and larger angles (45˚) respectively enhance heat transfer coefficients and turbulence intensity, but special attention should be paid to matching with airflow load; 4) Diameter differences between riser and downcomer pipes significantly affect system performance, with greater sensitivity to riser diameter variations due to two-phase flow characteristics and liquid working fluid density differences. This research elucidates the correlation between structural parameters and thermal performance in microchannel separated heat pipes, providing theoretical support for optimizing heat exchanger design and improving energy efficiency in data center composite cooling systems.