坝前冒泡现象的水气两相运移机理数值模拟

Numerical simulation of water-gas two-phase movement mechanism of bubbling phenomenon in front of dam

为分析黄壁庄水库在库水位骤升后出现冒泡现象的原因,保障水库安全运行,建立了一种耦合Level-Set法的含自由面渗流分析方法。该方法考虑了入渗过程中的气相可压缩性,能够直观地反映多孔介质中水气两相界面的运动与融合,可求解常规方法无法处理的气相参与的渗流问题。运用该方法模拟了该水库在不同蓄水过程下的坝前水气两相运移过程,结果表明:黄壁庄水库坝前水面出现冒泡现象是由水位骤升将铺盖内的空气包围,并随水体入渗压缩空气,出现憋气现象,直到达到突破压强时气体释放所致;蓄水过程是影响坝前水面冒泡现象发生与发展的关键因素。模拟结果与实际观测现象基本吻合,验证了该方法的合理性。

A coupled Level-Set method for the analysis of free surface seepage is established,which is meant to analyze the cause of bubbling phenomenon after the water level rose rapidly in Huangbizhuang Reservoir,and to ensure the reservoir is in safe operation. The gas phase compressibility during the infiltration process is considered,thus the movement and fusion of the water-gas two-phase interface in porous medium can be reflected intuitively during the infiltration process. This method can solve the seepage problem involving gas phase which cannot be solved by conventional methods. The two-phase movement processes in front of dam of Huangbizhuang Reservoir in different water storage processes were simulated with this method. The results showed that:the bubbling phenomenon of water surface in front of dam was caused by the sudden rise of the water level,which surrounded air in the blanket and compressed air with the water infiltration process,until the air pressure reached the break pressure,then air released;the key factor affecting the occurrence and development of the bubbling phenomenon is the water storage process. The simulation results are basically consistent with the actual observation results,which verifies the rationality of the method.