纤毛肋强化管内对流换热

Convective heat transfer enhancement in a circular tube with microfiber fin

为发展一种在提高换热的同时附加阻力较小的新型强化换热技术 ,对层流通道中单根纤毛肋的强化换热作用进行了简化的理论分析 ,入口条件为速度和温度充分发展 ,分析中注意到了肋表面传热系数远远大于壁表面传热系数的事实。结果表明纤毛肋能有效地强化传热 ,影响纤毛肋的强化换热效果的主要参数是肋的长径比 (D/ d )和肋与流体的导热系数之比 (λs/λf)。随着 D/ d和λs/λf 的增加 ,传热强化作用增强 ;在λs/λf 较小时 ,纤毛肋的强化换热作用增加很快 ,当λs/λf 较大时 ,继续增加λs/λf

In the interest of developing a novel heat transfer enhancement technique with high heat transfer rates and less additional pressure loss, the thermal performance of a single fiber fin in internal laminar flow was theoretically analyzed. The inlet temperature and velocity were assumed fully developed. The analysis was based on the fact that the heat transfer coefficient along the fin surface was far greater than that of the tube wall. Analytical results show that the fiber fins can effectively enhance heat transfer. The effect of a single fiber fin on the heat transfer enhancement is mainly dominated by two parameters: the fin length to diameter ratio ( D/d ) and the ratio of the thermal conductivities of the fin and the fluid ( λ s/ λ f). The heat transfer improves monotonously as D/d increase. The heat transfer enhancement depends strongly on λ s/ λ f when λ s/ λ f is relatively small, but the thermal conductivity ratio has little effect when λ s/ λ f is relatively large.