板翅式换热器入口流场的模拟及实验研究

利用PIV粒子图像测速仪和CFD数值模拟的方法,对板翅式换热器入口结构改进前后的流场进行了研究,发现其内部流场的流动与分布规律。由于原始入口结构的不合理导致漩涡、回流等现象存在,使得其内部的物流分配极不均匀。而对于添加了打孔挡板的改进型结构,物流分配的均匀性有了很大改善。实验结果和数值计算结果吻合良好,不仅验证了计算模型的正确性,而且证明PIV技术适合于研究复杂的流动结构。

A numerical and experimental investigation of the flow field at the entrance of plate-fin heat exchanger

The turbulent flow structure inside the entrance of plate-fin heat exchanger was characterized by using PIV experiments and CFD simulations.The experiments and computations were performed under similar conditions.Results were obtained for two distinct configurations,involving conventional and improved configuration.A series of velocity vector and streamline graphs of different cross-sections were achieved.The numerical and experimental results indicate that performance of fluid maldistribution in conventional entrance is very serious while the improved configuration with punched baffle can effectively improve the performance.Numerical results and the experimental data are in good agreement with each other.It validates that PIV and CFD are well suitable to investigate complex flow patterns.