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对带纵向涡发生器的椭圆管翅片换热器空气侧表面的换热和流动特性进行了三维数值模拟.深入分析了纵向涡对流场和温度场的影响,并通过场协同原理揭示了纵向涡强化换热的根本机理,即减小了速度和温度梯度之间的夹角,改善了速度场和温度场的协同性.在此基础上,对纵向涡发生器的布置位置(上游布置和下游布置)和纵向涡发生器的攻角α(15°,30°,45°,60°)进行了优化设计.结果表明:当纵向涡发生器布置于换热管下游时,具有更好的强化换热能力;在纵向涡发生器采用下游布置的前提下,当纵向涡发生器的攻角α=30°时,具有最佳的强化换热能力.
The three-dimensional numerical simulation of the heat transfer and flow characteristics of the elliptical tube-fin heat exchangers with longitudinal vortex generators was carried out. The effects of longitudinal vortices on the flow field and the temperature field were analyzed in detail. Longitudinal vortex enhances the fundamental mechanism of heat transfer, that is, the angle between velocity and temperature gradient is reduced and the synergy between velocity field and temperature field is improved.On this basis, the arrangement of longitudinal vortex generator And the downstream arrangement) and the angle of attack α (15 °, 30 °, 45 °, 60 °) of the longitudinal vortex generator are optimized.The results show that when the longitudinal vortex generator is arranged downstream of the heat exchange tube, Of the enhanced heat transfer capacity; longitudinal vortex generator in the downstream arrangement of the premise, when the longitudinal vortex generator angle of attack α = 30 °, with the best heat transfer enhancement.