带肋矩形直通道内的冷却空气换热特性研究

Study of the Heat Exchange Characteristics of the Cooling Air Inside a Straight Ribbed Rectangular Channel

采用ANSYS CFX商用软件对带肋矩形直通道内的冷却空气换热特性进行了数值计算,并与文献[4]的实验数据进行了对比,分析了雷诺数Re和肋片角度对努塞尔特数Nu的影响。结果表明:Nu数计算平均值与实验值的变化趋势一致,但计算结果大于实验值;由于肋片的扰流作用,在两个肋片之间的壁面区域产生了两个旋涡,强化了冷却空气与固体壁面的换热;随着Re数的增大,Nu数增大,平均摩擦阻力系数也增大;当肋片角度在45°～60°之间时,冷却通道的强化对流换热效果最好。

By using the commercial software ANSYS CFS,numerically calculated were the heat exchange characteristics of the cooling air inside a straight ribbed rectangular channel and compared were the calculation results with the test data obtained by Han.Furthermore,the influence of Reynolds and the angle of ribs on Nusselt number was also analyzed.It has been found that the average Nusselt number obtained from the numerical calculation assumes an identical variation tendency to the test values.The calculation results,however,were bigger than the test values.Due to the flow disturbance role played by the ribs,two vortexes will be produced in the zone between any two ribs,enhancing the heat exchange between the cooling air and the solid wall surfaces.With an increase of Reynolds and Nusselt number,the average friction resistance coefficient will also increase.When the angle of ribs falls in a range from 45 to 60 degrees,the intensified convection heat exchange effectiveness in the cooling channel is assessed as the best.