交错管束间湿空气-水蒸发冷却特性模拟

为研究交错管束间喷淋水-湿空气及管壁-喷淋水间传热传质特性，综合考虑了喷淋水在交错管束间运动及传热传质过程，采用基于DPM （discrete phase models）与WFM （wall film models）耦合的欧拉-拉格朗日方法，建立了交错管束间湿空气-水蒸发冷却传热传质特性分析模型.通过文献实验数据验证了模型的可靠性，最大误差仅为1.1%；模拟了运行参数对交错管束间湿空气-水传热传质性能的影响.结果表明，空气流量对交错管束间传热传质性能的影响要比喷淋水流量对其影响更加显著，因此可适当降低喷淋水流量提高循环水泵能效；干湿球温度升高会对交错管束间传热传质性能产生不利影响，但与干球温度相比，湿球温度对交错管束间传热传质影响更大；提高喷淋水温度可以改善喷淋水膜-管壁间的Nusselt数，但管束壁面平均温度也随之升高，从而降低冷水机组的性能.上述研究成果为交错管束热力设计计算提供依据. 

Simulation Analysis on Humid Air-Water Evaporative Cooling Characteristics Among Staggered Tube Bundles

Based on the Euler-Lagrange method coupled with DPM (discrete phase models)-WFM (wall film models),a new model was established to investigate the heat and mass transfer characteristics of spray water-humid air and spray water-tube wall among staggered tube bundlesand to design the movement of spray water among staggered tube bundles and the heat/mass transfer process.Firstly,the reliability of the model was verified according to the literature experimental data,showing only 1.1% maximum error.Secondly,the influence of operating parameters was analyzed for heat and mass transfer performance of humid air-wateramong staggered tube bundles.The results show that the influence of air flow rate on heat and mass transfer performance among staggered tube bundles is more significant than that of spray water flow.Therefore,the spray water flow rate can be appropriately reduced to improve the energy efficiency of circulating water pump.The increase of dry bulb temperature and wet bulb temperature will have a negative effect on the heat and mass transfer performance among staggered tube bundles.However,the effect of wet bulb temperature on heat and mass transfer performance among staggered tube bundles is greater than that of dry bulb temperature.Increasing the spray water temperature can improve the Nusselt number between spray water and tube wall,but the average temperature of tube bundle wall also increases,which means that the performance of the cooling-water machine is reduced.The above research results can provide a basis for the thermal design and calculation of staggered tube bundles.