高速掺气水流可压缩性研究

High speed aerated flow is a common and important flow phenomena in hydraopower project. After aerated the sound velocity of the flow will decrease significantly, as a result the flow compressibility effect become important. Study the compressibility effects of high velocity aerated flow to reveal the flow characteristics and special phenomena is a meaningful research topic. By theoretical analysis and numerical simulation methods, this study will establish aerated flow sound velocity model, reveal the aerated flow acoustic propagation, attenuation mechanism and dispersion characteristics, investigate the movement law of subsonic, transonic, supersonic aerated flow, reveal the the supersonic aerated flow shock wave characteristics, determine the pressure, air concentration and other field parameters distribution before and after shock wave, develop numerical algorithm for solving the compressible water-air two-phase flow, simulate and analysis the flow features of compressible aerated flow with free surface, study the critical flow phanomenon in discharge spillway tunnel, improve high-speed aerated flow awareness, provide technical support for the engineering design.

高速水流掺气是水电工程中一种常见而又重要的流动现象。水流掺气以后声速将显著降低，流动可压缩性效应明显增强。研究高速掺气水流的可压缩性效应，揭示其流动规律与特殊现象是一项有意义的研究课题。本研究将通过理论分析与数值模拟结合的方法，建立掺气水流声速模型，深入揭示掺气水流声波的传播规律、衰减机理及色散特性，研究亚、跨、超声速掺气水流运动规律，揭示超音速掺气水流的激波特征,确定激波前后掺气水流压力、掺气浓度等参数的变化规律，发展求解可压缩水气两相流的数值算法，模拟分析具有自由面的掺气水流可压缩流动特征，研究泄洪洞掺气水流临界流现象，提高对超高速掺气水流的认识，为工程实践提供理论支撑。

建立了掺气水流声速分析模型，导出了掺气水流声速色散方程，研究了掺气水流中压力波的传播和衰减规律，发现水流掺气会导致声速大大降低，而相间作用力和相间传热特性是影响掺气水流声速的根本因素。结合气泡动力学模型和两相流双流体模型，构建了线性波在泡状流中传播的数学模型，研究了气泡在声场环境下收缩膨胀的动力热力特性及其对压力波的散射效应，分析了气泡脉动引起的共振现象及压力波在共振频率附近的传播特征。发展了基于SIMPLE的全速流动算法，对高速掺气水流可压缩流动进行了数值模拟，分析了考虑可压缩性的水气两相流的流动特点和激波结构特征。结合试验研究和数值模拟方法，系统研究了掺气设施下游高速掺气水流的流速、压力分布及掺气浓度变化规律，指出掺气水流可压缩性问题的多样性和复杂性，提出了高水头大流量泄洪洞侧壁掺气设施设计优化原则和方法。研究成果具有重要的科学意义，并对高速水流掺气减蚀设计有一定指导作用。