Onset of Natural Convection in Gas-gas System Induced by Bottom-up Transient Mass Diffusion
Onset of Natural Convection in Gas-gas System Induced by Bottom-up Transient Mass Diffusion
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DOI：
10.1080/19942060.2010.11015334
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发表时间：
2010-01
影响因子：
6.1
通讯作者：
K. Tan;B. Tey;Y. Tan
中科院分区：
文献类型：
--
作者：
K. Tan;B. Tey;Y. Tan
摘要利用瞬态不稳定理论成功地预测了静止气体中瞬态质量扩散引起的对流的发生，并用计算流体力学（CFD）方法对其进行了模拟。对轻气体在停滞重气体中自下而上扩散进行了二维时变模拟。利用模拟结果计算瞬态瑞利数，采用Tan和Thorpe（1996和1999）的理论。模拟得到的瞬态最大瑞利数平均值为707，接近恒定热流密度下模拟底加热的理论值817。模拟的对流发生临界时间与理论预测值吻合较好。
Abstract: The onset of convection induced by transient mass diffusion in a stationary gas was successfully predicted with transient instability theory and simulated using a computational fluid dynamics (CFD) scheme. 2D time-dependent simulations were conducted for bottom-up diffusion of a light gas in a stagnant heavy gas. The results of simulations were used to calculate the transient Rayleigh number adopted from the theory of Tan and Thorpe (1996 and 1999). The average transient maximum Rayleigh number from the simulations is 707, which is close to the theoretical value of 817 for analogous bottom heating with constant heat flux. The simulated critical times of the onset of convection were in reasonably good agreement with the predicted values from theory.