Numerical Simulation of Vapor-Liquid Interfaces During Saturated and Subcooled Film Boiling

摘要CTS-9322481 Dhir 在垂直表面上的饱和或过冷膜沸腾过程中的汽液界面形状由Kelvin-Helmholtz不稳定性决定，而在水平表面上的膜沸腾过程中的界面形状由Raleigh-Taylor不稳定性决定。界面的演化和诱导流场控制着穿过界面的热质传递，进而控制着来自加热器表面的热传递。在这项研究中，一个完整的数值模拟的汽-液界面的演变和伴随的流场和温度场的蒸汽和液体。模拟将在不引入任何经验常数的情况下进行，并将包括界面不稳定性的线性和非线性增长。在第一阶段中，我们将只考虑二维问题，并使用谱配点法沿着SIMPLE算法对控制方程进行数值积分。数值结果还将产生壁面过热，在此温度下，加热器表面上不能支撑连续的蒸汽膜。从而为最小热通量的预测提供了完全的理论依据。数值计算的努力将得到文献中已经报道的实验数据的支持。如果认为有必要，将使用现有的实验设施来获得垂直和/或水平板上的所需数据。

ABSTRACT CTS-9322481 Dhir Vapor-liquid interface shape during saturated or subcooled film boiling on a vertical surface is governed by Kelvin-Helmholtz Instability whereas it is the Raleigh-Taylor instability that governs the configuration of the interface during film boiling on horizontal surfaces. The evolution of the interface and the induced flow field govern the heat and mass transfer across the interface and in turn the heat transfer from the heater surface. In this study a complete numerical simulation of the evolution of the vapor-liquid interface and the accompanied flow and temperature field in the vapor and the liquid is proposed. The simulation will be carried out without introducing any empirical constants and will include both linear and non-linear growth of the interfacial instabilities. In the first phase, the effort will be limited to only two dimensions, and spectral collocation method along with SIMPLE algorithm will be used to numerically integrate the governing equations. The numerical results will also yield the wall superheats at which a continuous vapor film could not be supported on the heater surface. Thus the results will provide a completely theoretical basis for prediction of minimum heat fluxes. The numerical effort will be supported with experimental data already reported in the literature. If deemed necessary, existing experimental facilities will be used to obtain the required data on vertical and/or horizontal plates.