圆台凹凸结构通道的流动传热性能和熵产研究

Study on flow and heat transfer performance and entropy generation in concave-convex channel with frustum of a cone

为提高换热器的结构强度和降低接触热阻,提出一种新型采用热冲压成形工艺的圆台凹凸板片。对径高比为3、6、12的圆台凹凸结构通道和径高比为6的圆柱和球型凹凸结构通道进行了数值研究,并探究了不同雷诺数下单侧和双侧凹凸表面通道的流动传热性能和熵产的分布规律。研究表明:单侧和双侧凹凸表面通道传热壁面的传热分布相似,但前者的流动传热性能要优于后者;当雷诺数从5000增大到20000时,圆台凹凸结构通道的摩擦因数比和综合传热因子均随着圆台径高比的增大而增大;当径高比一定时,通道的综合传热因子从大到小依次为球型、圆台和圆柱凹凸结构;此外,随着雷诺数的增大5种结构下通道的传热和摩擦熵产的比值会减小。

In order to improve the structural strength of heat exchanger and reduce the contact thermal resistance,a new concave-convex plate of frustum of a cone with hot stamping process was proposed.Numerical studies were carried out on the concave-convex structure channels of frustum of a cone with diameter height ratio of 3,6 and 12 and on those of cylinder and spherical shape structure with diameter height ratio of 6.The flow and heat transfer performance and entropy generation distribution of channels with one and two concave-convex surfaces under different Reynolds numbers were studied.The results showed that the heat transfer distribution on the heat transfer wall of channels with one and two concave-convex surfaces was similar,but the flow and heat transfer performance of the former was better than that of the latter.When the Reynolds number increased from 5000 to 20000,the friction coefficient ratio and comprehensive heat transfer factor increased with the increasing diameter height ratio of frustum of a cone.When the diameter height ratio was constant,the comprehensive heat transfer factor of the channel was a spherical shape,frustum of a cone and cylinder concave-convex structure from large to small.In addition,the ratio of heat transfer and friction entropy generation decreased with the increase of Reynolds number.