水气混合洞塞泄流溶解氧输移扩散的数值计算

为研究水气二相混合洞塞泄流欠饱和溶解氧输移扩散行为特性,揭示气体体积分数、进口溶解氧浓度、雷诺数等流动特征参数和洞塞尺寸等几何参数对溶解氧浓度恢复的影响规律,开展了水气二相混合洞塞泄流溶解氧输移扩散的室内模型试验,观测流速、压力和溶解氧浓度分布。建立了水气二相混合洞塞泄流溶解氧输移扩散数学模型,并利用物理模型试验数据对数学模型进行了验证。利用验证后的数学模型,分别计算不同进口气体体积分数、溶解氧浓度、雷诺数、洞塞长度和洞塞直径条件下水气二相混合洞塞泄流溶解氧浓度恢复情况。结果发现:气体体积分数越大,进口溶解氧浓度与饱和溶解氧浓度差值越大,雷诺数越小,溶解氧浓度增量越大;洞塞长度越长,洞塞直径越小,溶解氧浓度增量越大。

Oxygen transport and diffusion numerical simulation on water and air mixture of plug discharge

An experiment of the dissolved oxygen transport and diffusion with water and air mixture in plug discharge is established, in order to study the undersaturated dissolved oxygen behavior of water and air mixture plug discharge and illustrate the influence of air volume fraction, inlet dissolved oxygen concentration, Reynolds number and geometry size on dissolved oxygen concentration. Velocity, pressure and dissolved oxygen concentration are measured, respectively. A three-dimensional mathematical model of dissolved oxygen transport and diffusion is established to compute water and air mixture flow, and, it is validated by the experimental data. It is used to compute the dissolved oxygen distribution with different inlet air volume fraction, dissolved oxygen concentration, Reynolds number, length, and diameter of the plug section. The results show that the increment of dissolved oxygen concentration increases with increasing air volume fraction, and, increasing difference between inlet dissolved oxygen concentration and saturation dissolved oxygen concentration, respectively. It also increases with decreasing Reynolds number. Finally, it increases with increasing length of plug section, and increases with decreasing diameter of plug section.