坐标变换方法在过饱和气体计算中的应用研究

The application of coordinate transform on the gas supersaturation simulation

在水库开闸泻水过程中,高速水流掺气以及消能过程中水流的强烈碰撞会卷吸大量气体形成溶解气体过饱和现象,进而引起鱼类患气泡病死亡。此文引入气体向气泡界面和水体表面传质的机理,利用坐标变换对自由水表面边界进行特殊处理,在三维紊流两相流模型的基础上模拟气泡在水中的运动和溶解,从而计算过饱和气体的浓度分布,并将此模型运用在对葛洲坝饱和气体模拟预测中,还和实测值进行了比较。结果表明:运用坐标变换方法后的模型能更准确地模拟饱和气体浓度。

High TDG （Total Dissolved Gas） happened when a large volume of air entrained in a spillway flow and it＇s proved to be harmful to most fish species based on the many research done on the dams. In this paper, the theory of the mass transfer from gas to water-bubble interface and water surface was introduced, and coordinate transformation of free surface was employed to predict the hydrodynamics and TDG distribution based on an unsteady three-dimensional （3D） two-phase flow computational fluid dynamics （CFD） model. Good agreement between measured and numerical results in the case of application on the Gezhouba hydroelectric project shows the feasibility to carry on this numerical work.