环形内肋片圆管层流脉冲流动强化对流换热数值分析

为了解环形内肋片圆管中脉冲流动强化对流换热的机理,该文对这一现象进行了数值研究。数值计算结果表明:与具有相同Rem时的稳定流动相比,脉冲流动可使对流换热强化一倍以上,其强化效果与振荡频率、肋片高度和肋片间距有关;最佳量纲1振荡频率在400到1000之间,并随着Rem的增大而增加;对流换热强化的原因在于脉冲流动使由肋片引起的涡旋更加激烈,速度场和温度梯度场之间的协同性更好。

Numerical analysis of the enhanced convection heat transfer in an annular finned tube with laminar pulsating flow

The convection heat transfer enhancement induced by pulsating flow in an annular finned tube was investigated numerically. The numerical results show that the pulsating flow enhances the convection heat transfer more than twice that of steady flow at the same Re_m. The heat transfer enhancement depends on the pulsation frequency, the fin height and the fin pitch. The best dimensionless pulsating frequencies are 400(1 000) and they increase with increasing Re_m. The enhancement is due to the pulsating flow strengthening the vortex between the fins and improving the coordination of the temperature and velocity fields.