气-水两相混合流动特性对水下喷气推进系统性能有重要影响。针对宽速域下的气液两相混合弥散问题，采用欧拉-欧拉多相流模型耦合群体平衡模型，数值模拟了高表观气速（1.6~6.4 m/s）下的气-水两相混合弥散过程，对比分析了不同轴向位置下的截面气含率、气相速度和气相均匀性的变化规律。研究表明：随着气相表观流速增加，不同轴向位置的截面气含率和Sauter平均直径（SMD）增大，气含率、气相速度和均匀性的增幅逐渐减弱，相同轴向位置下的SMD最大值逐渐减小，逐渐趋向均匀；相同气相表观速度下，气相速度随轴向位置的增大增幅逐渐变缓；气含率、SMD和气相速度最大位置位于出口处，当气相表观速度由1.6 m/s转为3.2 m/s时，气含率和气相速度的增幅最大，分别为50%和21%；气含率均匀性变化趋势与气相速度均匀性变化趋势不同，位于出口附近截面处的气-水两相混合弥散的均匀性较好。

The flow characteristics of gas-water two-phase mixture have an important influence on the performance of underwater jet propulsion system. Aiming at the problem of gas-liquid two-phase mixing and dispersion in a wide range of gas superficial velocity, the Euler-Euler multiphase flow model coupled with the population equilibrium model is used to simulate the gas-water two-phase mixing and dispersion process at the gas superficial velocity (from 1.6 m/s to 6.4 m/s). The variation of gas holdup, gas velocity and gas phase uniformity at different axial positions are compared and analyzed. The results show that with the increase of gas superficial velocity, the gas holdup and Sauter mean diameter (SMD) at different axial positions increases, and the increase in magnitude of gas holdup, gas velocity, and uniformity gradually decreases. The maximum SMD at the same axial position decreases gradually and tends to be uniform. At the same gas superficial velocity, the increase of gas velocity gradually slows down with the increase of axial position. The maximum gas holdup and gas velocity are located at the outlet. When the gas superficial velocity is changed from 1.6 m/s to 3.2 m/s, the increase of gas holdup and gas velocity is the largest, which are 50 % and 21 % respectively. The change trend of gas holdup uniformity is different from that of the gas velocity uniformity. The uniformity of gas-water two-phase mixing and dispersion is better at the section near the outlet.

国家自然科学基金（U2241254）