Two-phase developing laminar mixing layer at supercritical pressures
Two-phase developing laminar mixing layer at supercritical pressures
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DOI：
10.1016/j.ijheatmasstransfer.2020.120687
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发表时间：
2019-12
影响因子：
5.2
通讯作者：
Branson Davis;Jordi Poblador-Ibanez;W. Sirignano
中科院分区：
文献类型：
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作者：
Branson Davis;Jordi Poblador-Ibanez;W. Sirignano
在超临界压力下，冷的液态正癸烷烃和热的氧气之间的剪切层的数值分析表明，可以建立一个定义明确的相平衡。考虑了可变性质，气相中的产物ρ μ在层流区域内显示出几乎恒定的结果，没有不稳定性。足够厚的扩散层在液-气界面周围形成，以支持连续介质理论和相平衡的情况。虽然分子在所有压力下都被交换为两种物质，但随着压力的增加，穿过界面的净质量通量发生变化。净蒸发发生在低压下，而净冷凝发生在高压下。对于正癸烷和氧气的混合物，转变发生在50巴左右。界面处的平衡值很快达到其下游渐近线。对于所有的情况下，配置文件的扩散平流量崩溃到一个类似的解决方案（即，一个独立变量的功能）。在150 bar下雷诺数大于239的两个阶段中，显示了边界层近似和相似性的有效性。其他压力的结果也是在高雷诺数下获得的。从而证明了边界层近似和相似性的有效性。然而，在非常高的压力下，类似的一维轮廓因不同的问题约束而异。
Numerical analysis of a shear layer between a cool liquid n-decane hydrocarbon and a hot oxygen gas at supercritical pressures shows that a well-defined phase equilibrium can be established. Variable properties are considered with the product ρ μ in the gas phase showing a nearly constant result within the laminar flow region with no instabilities. Sufficiently thick diffusion layers form around the liquid-gas interface to support the case of continuum theory and phase equilibrium. While molecules are exchanged for both species at all pressures, net mass flux across the interface shifts as pressure is increased. Net vaporization occurs for low pressures while net condensation occurs at higher pressures. For a mixture of n-decane and oxygen, the transition occurs around 50 bar. The equilibrium values at the interface quickly reach their downstream asymptotes. For all cases, profiles of diffusing-advecting quantities collapse to a similar solution (ie, function of one independent variable). Validity of the boundary layer approximation and similarity are shown in both phases for Reynolds numbers greater than 239 at 150 bar. Results for other pressures are also taken at high Reynolds numbers. Thereby, the validity of the boundary layer approximation and similarity are expected. However, at very high pressures, the similar one-dimensional profiles vary for different problem constraints.