应用FLUENT商业软件,模拟水蒸气在水平管束外遇冷凝结的流动情况,数值模型基于多相流混合物模型,模型中加入自定义函数以实现蒸汽向水的转换,利用有限体积法及SIMPLE算法和标准的k-ε双方程求解控制方程组,得出换热器的表面传热系数,内部混合相压力、速度、温度的变化分布。模拟了管外径d=20 mm、排列方式分别为顺排和错排,在不同的横向间距S1以及不同的纵向间距S2下的换热情况。结果表明不论是顺排还是错排均在S1/d=1．4, S2/d=1．2下结果最优,在最优情况下错排构成的换热器表面传热系数比顺排高1．7倍,为设计高效冷凝换热器提供参考。%This paper uses the software FLUENT to simulate the flow condition of the water vapor when it conden-ses as it comes to the outside horizontal tube bundle. The numerical model used in this paper is based on multi-phase mixture model. The user-defined function is added to the model to realize the conversion process of steam to water. It uses finite volume method, SIMPLE algorithm and k-ε double equation to solve the governing equations. And finally, the surface heat transfer coefficient of the heat exchanger well as the distribution of changes of the in-side mixed phase’ s pressure, velocity, and temperature, are worked out. This paper simulates the heat exchange process under the following conditions:pipes external diameter 20 mm ( d=20 mm) , exchangers arranged respec-tively in line and staggered, space varied by the horizontal spaces ( S1 ) , and s longitudinal spaces ( S2 ) . The re-sults show that the optimal result is obtained under the condition of S1/d=1. 4 and S2/d=1. 2 whether they are ar-ranged in staggered or in line. Under the optimal situation, the surface heat transfer coefficient of heat exchanger arranged in staggered is 1. 7 times higher than that in line. Therefore, this study provides reference for designing efficient condensing heat exchanger.
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