水平管气液二相分层流移动壁面模型的改进

Improvement of moving-wall model for horizontal gas-liquid two-phase stratified flow

针对基于Standard k-ε湍流模型的移动壁面模型在预测水平管气液二相分层流气相封闭关系时的不足,利用Launder-Spalding和Launder-Sharma低雷诺数k-ε湍流模型对移动壁面模型进行改进,其中湍流黏度和湍流雷诺数由修正湍流耗散率替代原定义的耗散率。通过数值模拟结果拟合出新的气壁和界面摩擦因子Blasius形式公式,计算结果发现,湍流模型的选择对固定壁面和移动壁面剪切的预测都有明显影响,其中Launder-Spalding低雷诺数k-ε湍流模型得到的气相封闭关系预测精度最高,在气、液相雷诺数9 000≤ReG≤50 000和20 000≤ReL≤30 000,压降预测相对均根误差为10.6%,为理论和实验研究提供了有价值的参考。

To modify unreasonable gas-flow closure relationship of horizontal stratified gas-liquid flow by moving- wall model based on standard k-ε turbulence model, Launder-Sharma and Launder-Spalding low Reynolds number k-ε models, in which the turbulence viscosity and turbulence Reynolds number were replaced by modified dissipation rate, were used for improving moving-wall model. New Blasius type equations for both gas-wall and interfacial fraction factors were derived from calculation results. The calculation results showed that the turbulence model had great effects not only on fixed wall but also on moving wall, and Launder-Spalding low Reynolds number k-ε model, which had a 10.6% relative root error for gas pressure drop prediction while gas and liquid Reynolds numbers respectively within 9 000 ≤ ReG ≤ 50 000 and 20 000 ≤ ReL ≤ 30 000, was in the best agreement in gasflow closure prediction. The present work provided valuable reference for theoretical and experimental researches.