微酒窝通道与圆柱面凹槽通道对流传热强化分析

结合对流传热场协同原理分析了微酒窝通道、圆柱面凹槽通道及低肋通道强化传热特点,研究发现酒窝与圆柱面凹槽强化传热主要原因为:1)增加近壁区流体扰动,促进酒窝或凹槽内部流体与主流之间的传热;2)酒窝与凹槽均可扩展传热面积,进而提高总传热量。与低肋通道相比,酒窝与圆柱面凹槽仅对其附近流体的流动产生影响,而对主流流体的流动影响较小,进而阻力增加较少。提出传热量单元性能参数PEC_A作为评价指标,酒窝通道综合性能参数略高于圆柱面凹槽通道,而远高于低肋通道。

Numerical Study of the Convective Heat Transfer Enhancement in the Micro Channel With Dimples and Cylindrical Grooves

According to the field synergy principle,the convective heat transfer characteristics in micro-channels with dimples,cylindrical grooves and low fins are numerically studied,and the reasons of the enhanced heat transfer in the dimple and cylindrical channels are in two ways:1)increasing the turbulence of fluid near the wall and enhancing heat transfer between the main stream and the fluid inside the dimples or cylindrical grooves;2)dimples and grooves can extend more surface for the total heat transfer.Compared with low fins,only the fluids inside or near dimples and grooves are influenced and dimples or grooves do not have much impact on the main stream such that more flow resistance can be avoided.We proposed a parameter PEC_a as the evaluation coefficient,and the results show that the PEC_A of the dimple channel is slightly higher than that of the cylindrical channel,but much higher than that of the low fin channel.