Abstract: The flow and heat transfer characteristics over solid wavy surface and flexible wavy surface are investigated with large eddy simulation.For the solid wavy surface,it is found that smaller wave amplitude of wavy surface does not form the recirculation in the valley.When a/λ is increased to 0.03,the flow separation appears in the valley,and the range of recirculation area becomes broader as the amplitude increases.The spindle-shaped spots with higher Nusselt number value are observed in the up-slope of the wavy surface.As the value of a/λ varies from 0.01 to 0.04,the local time-averaged Nusselt number is enhanced about 63.5% and comprehensive coefficient is increased by 0.5112.For the flexible wavy surface,the results indicate that periodic fluctuation of the wavy surface induces a periodic variation of pressure.It is also found that the spindle-shaped spots with higher Nusselt number value appear in the up-slope part of the wavy surface.When the value of a/λ varies from 0.01 to 0.04,the time-averaged local Nusselt number and comprehensive coefficient are increased by 173.1% and 1.1232,respectively. Compared with the solid wavy surface,the flexible wavy wall will remarkably enhance the heat transfer in the same amplitude and consumption of fluid pumping power.

Key words: large eddy simulation, wavy surface, heat transfer enhancement, flow drag reduction

摘要： 采用大涡模拟方法,对流体在刚性及柔性波纹面上的流动与传热特性进行了数值研究。结果表明:对于刚性波纹面,当振幅与波长比值(a/λ)较小时,波谷区域无回流现象;当a/λ增大至0.03时,波谷区域出现回流区,且回流区域随波幅的增加而增大;波纹面上坡部位沿展向出现较高Nusselt数的斑块;当a/λ从0.01增至0.04时,时均Nusselt数提高了近63.5%,综合系数增加了0.5112。对于柔性波纹面,其压力分布也呈现周期性变化;且在上坡位置也出现较大Nusselt数斑块;当a/λ从0.01增至0.04时,时均Nusselt数值提高了173.1%,综合系数增加了1.1232。与刚性波纹面相比,在消耗相同流体输送泵功时,柔性波纹面具有更好的传热效果。

关键词: 大涡模拟, 波纹面, 强化传热, 流动减阻