涡产生器倾角对换热器内流动与换热特性的影响

为优化涡产生器强化传热的性能,通过改变三角翼式涡产生器的倾角,数值分析了倾角变化对板式换热器通道内流动与换热特性的影响,倾角变化范围为-30°～30°。获得了不同倾角下通道内的纵向涡、涡量分布,换热及阻力特性。结果表明涡产生器倾斜方向对流动与换热的影响不同,存在最佳的涡产生器倾角-10°,使得换热通道内涡产生器强化换热的性能最优;改变倾角可进一步提高涡产生器的强化传热性能,不同倾角对应努塞尔数和热性能评价因子间的最大差值分别达到8.9%和5.7%。

Effects of Inclination Angle of Vortex Generator on Fluid Flow and Heat Transfer Characteristics of Heat Exchanger

To improve the heat transfer enhancement performance of vortex generator, the inclination angle of a delta winglet vortex generator is proposed. The effects of inclination angle in the range between -30° and 30° on the fluid flow and heat transfer characteristics are numerically studied in the flow channel of plate heat exchanger. The details of the longitudinal vortex, vorticity, heat transfer and pressure loss in the flow channel are obtained under different inclination directions and different inclination angles. The results showed that inclination direction has apparent effect on the characteristics of fluid flow and heat transfer. There is an optimum inclination angle with -10° for the best heat transfer performance. Heat transfer performance of vortex generator can be further improved by changing the inclination angle. The maximum differences in Nusselt number and thermal performance factor between different inclination angles are approximately 8.9% and 5.7%, respectively.