Dissimilar turbulent heat transfer enhancement by Kelvin-Helmholtz rollers over high-aspect-ratio longitudinal ribs
Dissimilar turbulent heat transfer enhancement by Kelvin-Helmholtz rollers over high-aspect-ratio longitudinal ribs
复制标题
通过开尔文-亥姆霍兹滚子在高纵横比纵向肋上增强异种湍流传热
DOI：
10.1017/jfm.2022.915
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发表时间：
2022
影响因子：
3.7
通讯作者：
Y. Kuwata
中科院分区：
文献类型：
--
作者：
Kohei Aono;Manabu Aoyagi;Chihiro Inoue;Y. Kuwata
通过直接数值模拟摩擦雷诺数下的大高宽比纵向肋条，研究了与Kelvin-Helmholtz不稳定性相关的横向滚子的被动强化换热。将温度作为具有Prandtl数单位的被动标量，讨论了热传递和动量传递之间的相似性。结果表明，大长宽比的纵肋导致雷诺模拟的有利破缺，即换热效率的提高超过了摩擦阻力的提高。雷诺模拟的有利破裂可以归因于与雷诺剪切应力相比，湍流热通量的增强，而肋骨诱导的二次流则起到了减少雷诺模拟有利破裂的作用。条件平均统计表明，高压区伴随着横展滚子，抑制了横展滚子诱导的扫掠和抛射运动，导致雷诺切应力比湍流热流小。
Passive heat transfer enhancement by spanwise rollers associated with the Kelvin–Helmholtz instability was studied through direct numerical simulations of high-aspect-ratio longitudinal ribs at the friction Reynolds number . The temperature was treated as a passive scalar with Prandtl number unity to discuss the similarity between the heat and momentum transfer. The results reveal that the high-aspect-ratio longitudinal ribs lead to a favourable breakdown of the Reynolds analogy, that is, the enhancement of the heat transfer rate surpasses that of the frictional resistance. The favourable breakdown of the Reynolds analogy can be attributed to the enhanced turbulent heat flux compared with the Reynolds shear stress, whereas the rib-induced secondary flow plays a role in reducing the favourable breakdown of the Reynolds analogy. The conditional average statistics reveal that the high-pressure region accompanied by the spanwise rollers suppresses the spanwise roller-induced sweep and ejection motions, leading to smaller Reynolds shear stress than for the turbulent heat flux.