Direct numerical simulations of Rayleigh-Benard convection of a gas-liquid medium near its density maximum
Direct numerical simulations of Rayleigh-Benard convection of a gas-liquid medium near its density maximum
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气液介质密度最大值附近瑞利-贝纳德对流的直接数值模拟
DOI：
10.1016/j.applthermaleng.2020.115387
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发表时间：
2020
影响因子：
6.4
通讯作者：
I. B. Palymskiy
中科院分区：
文献类型：
--
作者：
Jia-Jia Yu;Yu-Peng Hu;Chun-Mei Wu;You-Rong Li;I. B. Palymskiy
碳氢化合物的氧化是一种常用的化学反应，因为其产品在增塑剂，树脂和其他中间制造过程中具有突出的经济价值。然而，在这种化学反应中，气液介质存在着显著的爆炸危险。因此，了解气液介质中的流场和热场对于控制对流、防止过热和防止爆炸在工业中是十分必要的。本文介绍了气液介质在密度极值附近的瑞利-巴萨纳德对流的综合数值计算。分析了密度反演参数和瑞利数对瑞利-布氏对流流动稳定性、流型演化和换热能力的影响。结果表明：随密度反演参数的增大，定常对流和非定常对流发生的临界瑞利数增大；流型演化在很大程度上依赖于密度反演参数。对流强度和换热能力随瑞利数的增大而增强，随密度反演参数的增大而减弱。成功地建立了基于瑞利构件和密度反演参数的底壁平均努塞尔数的标度关系。此外，基于尺度相关性的预测结果与模拟结果一致。
Oxidation of hydrocarbons is a commonly used chemical reaction due to the prominent economic value of its products in plasticizers, resins and other intermediate manufacturing processes. However, there is a significant explosion danger of the gas-liquid medium in this chemical reaction. Thus, it is necessary to make sense of the flow and thermal fields in the gas-liquid medium to manage the convection, avoid overheating and prevent explosion in the industry. A comprehensive numerical work of Rayleigh-Bénard convection of a gas-liquid medium near its density maximum was presented in this paper. The influences of the density inversion parameter and Rayleigh number on the flow stability, flow pattern evolution, and heat transfer ability of Rayleigh-Bénard convection were analyzed. The results show that the critical Rayleigh numbers for onsets of a steady convection and an unsteady convection rise with the increase of the density inversion parameter. The flow pattern evolution strongly relies on the density inversion parameter. The strength and heat transfer ability of Rayleigh-Bénard convection are enhanced as the Rayleigh number rises, while they are suppressed along with the density inversion parameter. A scaling relationship for the average Nusselt number on the bottom wall in terms of the Rayleigh member and density inversion parameter is successfully proposed. In addition, the predicted results based on the scaling correlation are consistent with those from simulations.