翅片管蒸发式冷凝器换热特性研究与结构优化

Research on Heat Transfer Characteristics and Structure Optimization of Fin Tube Evaporative condenser

利用翅片管换热器可大幅增加换热面积的优点,将其与光管蒸发式冷凝器相结合,进一步的提升蒸发式冷凝器换热性能。基于VOF模型,采用Lee模型描述气液两相双向传热传质过程中的质量与能量传递,同时考虑气液剪切力的影响,建立了翅片管蒸发式冷凝器气液两相传热传质三维数值模型。模拟光管蒸发式冷凝器的冷却过程,模拟结果与试验结果吻合良好。进而模拟研究了管型、翅片间距、纵向管排、迎面风速等因素对翅片管蒸发式冷凝器换热性能的影响规律。模拟结果表明,翅片管最佳间距为5 mm,换热量比光管提高了22.1%;随着管排的增加,换热量增加幅度减小,最佳换热区域在第一排,前六排换热量占据了总换热量的82.3%;最佳间距下的最佳迎面风速为2.91 m/s。

Due to the large heat transfer area,the finned tube heat exchanger can be combined with a smooth tube evaporative condenser to further improve the heat transfer performance of the evaporative condenser.Based on the VOF model,the Lee model is used to calculate the mass and energy transfer in the process of gas-liquid two-phase two-way heat and mass transfer.Incorporated the influence of the gas-liquid shear force,three-dimensional numerical model of the gas-liquid two-phase in evaporative condenser is established.Compared with the experimental results,the simulation results are in good agreement with the experimental results.The effects of tube shape,fin spacing,longitudinal tube row and oncoming wind speed on heat transfer performance are studied.The results show that the best spacing of finned tube is 5 mm,and the heat transfer is 22.1%higher than that of smooth tube.With the increase of tube rows,the rate of the increase in heat transfer becomes smaller.The best heat transfer area is in the first row and the heat exchange of the first six rows accounted for 82.3%of the total heat exchange.The best oncoming wind speed under the best spacing is 2.91 m/s.