多元平行流冷凝器传热流动性能研究

平行流冷凝器空气侧采用间断型扩展表面的波纹型百叶窗翅片,制冷剂侧采用小水力直径的非圆截面微通道多孔铝制扁管,选用适合于该微尺度强化换热结构的传热和压降关联式,对某规格的平行流冷凝器建立数学模型并在一定工况下进行数值模拟.结果分析表明,制冷剂在非圆截面微通道内的冷凝过程中,表面张力对表面传热系数的强化效果明显;通过改变流程数和各流程管数来改变冷凝过程中的流通截面而达到调整流速的作用,从而可以保持较高的冷凝换热系数和较低的流动压降,与常规换热器相比具有显著的优越性.

Study on Heat Transfer and Flow Characteristics of a Multi- unit Parallel- flow Type Condenser

For parallel - flow type condensers, the louvered fin is adopted for air side and the micro- channel with rectangle sections and small hydraulic diameter is adopted for refrigerant side. The formulas suitable to this special configuration were presented to calculate the heat transfer coefficient and pressure drop. Then the mathematic model was established to simulate the performance of the condenser. The results show that during the process of flow and condensation of the refrigerant, surface tension plays a significant role in the enhancement of heat transfer. In the parallel flow type condenser with gradually decreasing flow section areas, it can keep high heat transfer coefficient and low pressure - drop.