涡强化扁管管片散热器传热特性及场协同原理分析

NUMERICAL SIMULATION ON HEAT TRANSFER PERFORMANCE OF THE FIN-AND-FLAT TUBE BANK HEAT EXCHANGER WITH VORTEX GENERATORS AND ANALYSIS WITH FIELD SYNERGY PRINCIPLE

本文以空气为介质(Pr=0．698),通过数值模拟的方法在Re=400-2000的范围内对涡强化扁管管片散热器内周期性充分发展的层流流动进行了模拟分析,说明了在不同Re下,涡产生器横向间距δ和涡产生器攻角β改变时对局部NuLocal、横断面上的平均Nub和整体平均Nut的影响,以及对局部协同角θLocal、横断面上的平均协同角θb 和整体平均协同角θt的影响,通过比较分析得出协同角的变化趋势与换热强烈程度的变化趋势是完全和场协同原理相符合的,说明纵向涡强化换热的根本机理是改善了速度场与温度场的协同。

The periodically fully developed laminar heat transfer in the fin-and-fiat tube bank heat exchanger with vortex generators has been investigated by numerical analysis in the Reynolds number range of 400-2000. A set of laminar heat transfer predictions are presented to demonstrate the effects of the Reynolds number, span-wise position of VGs （δ） and the attack angle of VGs（β） on the local, span-averaged, total-averaged Nusselt number and on the local, span-averaged, total-averaged intersection（synergy） angle. By comparison of the Nusselt number with the synergy angle, it is found that the fundamental mechanism of heat transfer enhancement by the longitudinal vortices is the improvement of the synergy between velocity and temperature gradient.