一种绕流管束雷诺数和特征尺寸计算新方法

摘要

A new method for calculating Reynolds number and the characteristic length in detou-ring tube bundles is proposed.The characteristic length is related not only to the tube diameter, but also to the tube spacing and line spacing of the bundle as well as the flow rates between tubes.Based on the software Fluent,a 2-D simulation model is built to study the airflow sweep-ing across the tube bundles and the standard k-εmodel is adopted.The pressure drop of detouring flow is equivalent to the drop along the path,the pressure drop variation under different bundle sizes and flow rates is analyzed,and the relationship of Reynolds number and characteristic length with bundle structural parameters and flow rates is studied too.The results show that the new method to calculate the characteristic length could describe the influence of structural parameters and flow rates on characteristic length in detouring tube bundles more truly.%针对匀速进气横掠管束的流动，采用Fluent软件和标准k-ε模型，建立二维网格进行了数值模拟。以绕流管束的沿程压降为流道流动压降的当量压降，分析了不同管束尺寸和不同流速下流动压降的变化规律，得到了绕流雷诺数及其特征尺寸随管束结构参数和流速的变化关系，据此提出了一种绕流管束雷诺数和特征尺寸计算的新方法。数值模拟结果表明，在绕流管束雷诺数及其特征尺寸计算中同时考虑管外径、管间距、排间距和管间流速的影响时，得到的绕流管束雷诺数及其特征尺寸能更真实地反映绕流管束结构尺寸和流速对流道或流场特征尺寸de的影响。