矩形涡流发生器结构参数对圆形换热管传热特性的影响

Effects of Structural Parameters of Rectangular Vortex Generator on Heat Transfer Characteristics of Circular Heat Exchange Tube

为了提高圆形换热管的换热效率,采用SST(shear-stress transport)k-ω湍流模型(k为湍动能,ω为耗散率),对内置矩形涡流发生器的圆形换热管进行了数值模拟研究,分析了涡流发生器长高比和攻角对流动和传热特性的影响。结果表明:V型排布的4个矩形涡流发生器产生了两对反向旋转的纵向涡流,增强了冷热流体的混合,改善了圆管内的场协同,提高了换热性能;随着涡流发生器长高比的增加,换热管性能比较指标增大,但是增加幅度逐渐减小,当长高比为2时,换热管具有较好的综合性能;随涡流发生器攻角的增大,性能比较指标先增大后减小,当攻角为30°时,多数工况下性能比较指标具有最大值,换热管具有最佳综合性能。可见,矩形涡流发生器的结构参数对换热管的传热特性有巨大影响,研究结果可为换热管的设计和改进提供参考。

In order to improve the heat transfer efficiency of circular heat exchange tube,the numerical simulation of circular heat exchange tube with rectangular vortex generator was carried out using shear-stress transport(SST)k-ωturbulence model(k is turbulent kinetic energy,ωis dissipation rate).The effects of the length-height ratio and the attack angle of the vortex generators on the flow and heat transfer characteristics were analyzed.The results show that four rectangular vortex generators generate two pairs of longitudinal vortices rotating in opposite directions,which enhance the mixing of hot and cold fluid,improve the field synergy in the circular tube and improve the heat transfer performance.The performance evaluation criterion of the heat exchanger tube increases with the increase of the length-height ratio of the vortex generator.With the increase of length height ratio of vortex generator,the increase range of performance evaluation criterion decreases gradually.When the length-height ratio is 2,the heat exchange tube has a better comprehensive performance.With the increase of the angle of attack of the vortex generator,the performance evaluation criterion increases at first and then decreases.When the angle of attack is 30°,the performance evaluation criterion has the maximum value under most cases,and the heat exchanger tube has the best comprehensive performance.It can be seen that the structural parameters of rectangular vortex generator have great influence on the heat transfer characteristics of heat exchange tubes,and the results can provide reference for the design and improvement of heat exchange tubes.