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利用CFD的方法建立了简单、准确计算板翅式换热器平直翅片在层流和湍流区域性能的数值模型。在湍流区域使用低雷诺数湍流模型来替代壁面函数的方法,f因子的平均绝对误差从22.7%降低到7.9%;并用湍流普朗特数模型代替FLUENT软件中默认的湍流普朗特数常量(0.85)使得j因子平均绝对误差从17.9%降低到6.9%;通过以上两个措施使得CFD方法能够更准确预测平直翅片性能。对18种具有不同几何结构参数的平直翅片进行数值模拟;计算结果表明:翅片间距、高度对性能有较大影响而翅片厚度影响较小。同时,回归了j和f因子关联式。
A simple and accurate numerical model for calculating the performance of flat-finned plate-fin heat exchanger in laminar and turbulent flow regions is established by CFD method. The average absolute error of f factor was reduced from 22.7% to 7.9% using the low Reynolds number turbulence model instead of the wall function in the turbulent region. The turbulent Prandtl number model was used to replace the default turbulence Prandtl number constant in FLUENT software 0.85) reduced the average absolute error of j factor from 17.9% to 6.9%. By the above two measures, the CFD method can predict the flat fin performance more accurately. Eighteen kinds of straight fins with different geometrical parameters were simulated. The calculation results show that the fin spacing and height have great influence on the performance and the fin thickness has little influence. At the same time, regression j and f factor correlation.