中文摘要：

利用数值模拟的方法，在适体坐标系下对渐缩通道中层流状态下二次流强度及其对流换热的关系进行了数值分析研究．分析了不同的渐缩角a和Re对渐缩通道内二次流及对流换热的影响．结果表明：随着渐缩角的增大，渐缩通道截面上的二次流速度、通道内的阻力系数也相应的增大，通道内平均努塞尔数Num和二次流强度Se数均随着渐缩角和Re的增大而增大，二次流对Num的增强起到一定作用，渐缩通道较直方管有一定的强化传热作用，但这种强化作用与渐缩角的变化规律并不相一致．

英文摘要：

The relationship between the strength of secondary flow and the convective heat transfer in the convergent square duct is studied under body fitted coordinate system by using a numerical simulation approach. The impact of different convergent angle a and Re on the secondary flow and the convective heat transfer in the convergent square duct is analyzed. The results show that with the increase of α and Re,the secondary flow velocity on the convergent cross section and the friction factor in the channel increase accordingly,and both the average Nusselt number Num and the strength of secondary flow Se increase with the increase of α and Re. The secondary flow plays a certain role in the increase of Num. Compared to straight square duct,convergent duct can enhance the heat transfer,however,the enhancement does not coincide with α.