横掠叉排管束传热特性的数值研究

Numerical investigation on heat transfer characteristics of staggered tube bundles in cross flow

为验证基于大管径实验数据的经典传热关联式在小尺度管束传热问题上的适用性,针对横掠叉排管束的管外流动换热特性进行了数值研究。在建立了确定变几何结构合理网格密度的方法基础上,探究了大参数范围内管径、管间距比和雷诺数对管外传热努塞尔数和流动特征的影响规律。结果表明:(1)管排流动马赫数小于0.1时,雷诺数不变,管径对管外努塞尔数影响很小,不同管径对应的管外流动特征差别很小;(2)管间距比通过改变管外的流动特征来影响管外努塞尔数,且雷诺数和管径不变时,努塞尔数分布在特定管间距比范围内存在峰值区;(3)需要更为具体的分段函数来拟合传热关联式以准确预测努塞尔数。

In order to verify the applicability of the classical heat transfer correlations mostly based on the experimental data of large tube diameter on heat transfer of small-scale tube bundle,the flow and heat transfer characteristics outside the staggered tube bundle in cross flow were numerically investigated.With a new method to determine the reasonable mesh density of variable geometry,the effects of tube diameter,tube pitch ratio and Reynolds number on Nusselt number and flow characteristics outside the tube bundle were studied within a large parameter range.The following conclusions can be obtained:(1)when flow Mach number was smaller than 0.1 and Reynolds number kept constant,the tube diameter had little effect on the Nusselt number because the flow characteristics outside the tube varied slightly with tube diameter;(2)the tube pitch ratio affected Nusselt number by changing the flow characteristics outside the tube,and there was a peak area of Nusselt number within a specific range of tube pitch ratio when the Reynolds number and tube diameter kept constant;(3)a more specific piecewise function was needed to fit the heat transfer correlation to accurately predict the Nusselt number.