横掠周期性密集管束流动换热的数值模拟

在较宽的雷诺数范围内,使用CFD软件、SIMPLE算法和QUICK格式,对流体横掠不同管间距的顺排密集型管束,在周期性充分发展段的流动换热进行了数值模拟.选用几何间距与经验公式中相同的管束模型进行计算,将数值结果与前人已存在的经验公式和实验结果进行比较,确保数值模拟方法的正确性.通过分析3种不同计算模型的流场、换热系数等,验证了针对高度密集管束采用周期性边界条件和对称性边界条件的合理性.将其与大间距顺排管束的流动换热特性进行对比,结果表明,密集管束换热系数最高可达大间距管束换热系数的3倍,可为工业上换热器管排布置方式提供参考.

Numerical Simulation of Periodically Fully Developed Flow and Heat Transfer in Crossflow over Intensive Tube Banks

To investigate the effect of the longitudinal pitch and the transverse pitch on the convective heat transfer in the crossflow over intensive in-line tube banks,an analytical study using the CFD (computational fluid dynamics) code and the SIMPLE (semi-implicit method for pressure-linked equations) algorithm with the QUICK (quadratic upwind interpolation of convective kinematics)scheme was performed.A bundle model with the same longitudinal reduction and transverse pitch as those in the empirical formula was selected in the simulation.By comparison of numerical results with existing empirical formulas and experimental results,the correctness of the numerical simulation method was ensured.Three kinds of bundle models were simulated.By analyzing the results of the flow field and the heat transfer coefficient of tube banks,it indicates that the periodic boundary conditions and the symmetryical boundary conditions given in the model are reasonable.By comparing the flow and heat transfer coefficient characteristics of the intensive and sparse array tube banks,the results show that the heat transfer coefficient of intensive tube bundles is up to three times as big as that of sparse tube banks.The conclusion can provide a reference to the arrangement of industrial heat exchanger tubes.