脉动流与波纹壁通道耦合强化换热及优化研究

In order to obtain the channel enhanced heat transfer technology with good energy saving effect, the enhanced heat transfer performance mechanism and flow characteristics under the coupling effect of the corrugated channel wall profile and the inlet pulsating flow were studied. The flow and heat transfer phenomena in three kinds of corrugated channels under the sinusoidal pulsating flow were compared and analyzed. The results show that under the studied Reynolds number range, the arc channel has the lowest flow resistance, the sinusoidal channel has the best heat transfer enhancement effect, and the Bezier channel has both moderate heat transfer enhancement and flow resistance improvement. When the Reynolds number is 5 000 or 10 000, the comprehensive performance of the Bezier channel is significantly better than that of the other two kinds of channels, relatively improved by more than 20%. When the Reynolds number increases to 20 000, the comprehensive performance is only slightly smaller than that of the arc channel. The addition of the wall structure excites a high turbulent kinetic energy region near the wall, which enhances the heat and mass transfer between the fluid near the wall and the mainstream, and the high-temperature fluid near the wall is periodically transported to the mainstream. Furthermore, with the Bezicr channel featuring excellent comprehensive performance selected and the comprehensive performance evaluation criterion chosen as the objective function, a fast and accurate optimization method of the wall profile based on the genetic algorithm is established. The optimization results show that the Bezier structure tends to be arranged to the right and rear is conducive to the improvement of comprehensive performance, and the improvement of the optimal channel reaches 38. 7%. The change of the channel structure affects the distribution position and intensity of the secondary vortex, which further improves the temperature distribution on the downstream side and alleviates the problem of local overheating.