一种适用于复杂结构管翅式换热器传热性能分析的高效数值方法

A High Efficiency Numerical Method for Analyzing the Heat Transfer Characteristics of Flat Tube-bank-fin Heat Exchanger with Complex Structure

特征正交分解POD(Proper orthogonal decomposition)低阶模型是一种对物理问题的高保真加速技术,被广泛应用于工程实际.本文针对带涡产生器的扁管管翅式换热器这一复杂结构中流动与传热特性问题,构建了适用于求解该类问题的POD低阶模型.采用SVD(Singular Value Decomposition)方法从样本中提取基函数,将基函数与谱系数结合,探究空气侧雷诺数、翅片间距、横向管间距这3种参数变化下传热单元的温度场和速度场.研究结果表明:POD方法对于复杂结构的多变量稳态问题是适用的,重构温度场的平均相对误差最大值为0.0047%,重构速度场的平均相对误差最大值为0.036%.而且,POD方法不仅计算精度高,在计算速度上也平均高达SIMPLE算法的556倍.本文POD方法在扁管管翅式换热器传热特性方面的研究尝试,拓展了该方法的工程应用范围,对于提高复杂结构换热器数值设计效率有一定的理论参考价值.

The proper orthogonal decomposition(POD)reduced-order model is an efficient method popularized in the engineering field,which can significantly reduce the computational load.The POD method can simplify the solving process of complex problems and can greatly reduce the calculation time under the premise of ensuring the calculation accuracy.It is a high-fidelity acceleration technology for physical problems.In this paper,a POD reduced-order model(ROM)is established and the flow and heat transfer characteristics in a complex structure of a flat tube-bank-fin heat exchanger arranged with vortex generators is researched.The SVD(Singular Value Decomposition)method is used to extract the basis functions from the samples,the basis function is combined with the spectral coefficient.The air side Reynolds number,fin spacing and transverse tube spacing are respectively taken as the variation parameters to analyze the temperature fields and velocity fields of the heat transfer unit under single-parameter variation,two-parameter variation and three-parameter variation.The results show that the POD method is applicable to solve the multivariable steady-state problem of complex structures.The maximum average relative error of the reconstructed temperature field is 0.0047%while the maximum average relative error of the reconstructed velocity field is 0.036%.Moreover,the POD method not only has high calculation accuracy,which is also average 556 times of the FVM in calculation speed.The conclusions obtained by this study have certain theoretical reference for structural parameter design and operation optimization of flat tube-bank-fin heat exchanger.