Abstract:

Traditional numerical simulation methods have shortcomings of large amount of calculation, longer calculating time, so they can not meet the development requirement of modern industry. A POD reduced-order model for flat tube fin heat exchanger is constructed by combining body-fitted coordinates with proper orthogonal decomposition. The flow and heat transfer process of flat tube fin heat exchanger is calculated under unique heat flux boundary conditions. And its calculation results are compared with calculation results of the finite volume method (FVM). Results show that the POD method is feasible for solving the flow and heat transfer problems in complex structures such as flat tube fin heat exchangers and that can accurately capture the temperature field and velocity field information for different parameters. The relative deviation increases with the number of variables between the POD and FVM. The relative average maximum error of reconstructed velocity fields and temperature fields are 1.90% and 0.308%, respectively. Both cases are three-variable conditions. The POD method can increase the calculating speed of the traditional FVM by 3093.4 times under the premise of ensuring the calculating accuracy. This study has certain theoretical reference for improving the numerical design efficiency of flat tube fin heat exchangers and expanding the engineering application field of POD method.

Key words: heat transfer, heat exchanger, flat tube, reduced-order model, uniform heat flux, velocity field reconstruction, numerical simulation

摘要：

传统的数值模拟方法计算量大，计算时间长，很难满足现代工业发展的需求。以扁管管翅式换热器为例，采用适体坐标与最佳正交分解（POD）相结合的方法构建了低阶模型，在等热流边界条件下对扁管管翅式换热器中流动与传热过程进行计算，并将POD计算结果与有限体积法（FVM）计算结果进行了对比。结果表明：POD方法能准确地捕捉到不同数量参数变化情况下的温度场及速度场信息。对于3变量工况重构速度场及温度场的相对偏差平均值的最大值分别为1.90%、0.308%。采用POD方法在保证计算精度的前提下将FVM计算速度最大能提高3093.4倍。研究对于提高扁管管翅式换热器数值设计效率、拓展POD方法的工程应用领域有一定的理论参考价值。

关键词: 传热, 换热器, 扁管, 低阶模型, 等热流, 速度场重构, 数值模拟