冷箱U型和Z型集管流体分布特性数值模拟

Numerical investigation on flow distribution characteristics of U type and Z type manifold of cold box

针对大型冷箱的U型和Z型集管内流体分布特性进行数值模拟研究。依据集管内压力分布规律性,探讨了不同雷诺数Re与结构因素对其内流体分布的实际影响;采用多孔介质模型分析给出了板翅式换热器对集管内流体分布的影响作用;最后对大型冷箱集管布置提出了流体均配优化方案。研究表明,U型集管内流体分配优于Z型集管;随着Re增加,U型集管流体分布趋于均匀而Z型集管变得不均匀;随着支管阻力增加所致的集管压降增加能使集管内流体分布趋于均匀;支管长度增加或支管管径减小,可使集管内流体分布趋于均匀,但会导致较大额外压降。依据以上结论提出的大型冷箱集管优化方案可在较大改善实际流体分布同时有效降低集管压降。

Numerical simulation was conducted for obtaining flow distribution characteristics of U type and Z type manifold structures in the cold box, Reynolds number and the geometric factors were examined based on the different pressure distribution characteristics of the manifold. A porous media model was presented for analyzing the influence of plate-fin heat exchanger for the flow distribution. Finally, an optimized scheme for improving the flow uniformity was proposed. The results show that the flow distribution of the U type manifold is better than that of the Z type. With the Reynolds number being increased, the flow distribution of the U type manifold is being improved, while that of Z type is becoming deteriorated. The flow imbalance can be improved with increasing the pressure drop by the flow resistance. Increasing the length of the branch tubes or reducing the cross-sectional area of the branch tubes, the flow distribution of U type and Z type manifold were both improved but more extra-cost caused by large pressure drop. Here, a new optimized strategy is proposed for greatly helping to achieve the uniform flow distribution of manifold in the cold box with the pressure drop obviously reduced.