Air bubble entrainment is a phenomenon that can significantly reduce the efficiency of liquid motion in piping systems. In the present study, the bubble formation mechanism in a globe valve with 90% water fraction flow is explained by visualization study and pressure oscillation analysis. The shadowgraph imaging technique is applied to illustrate the unsteady flow inside the transparent valve. This helps to study the effect of bubbles induced by the globe valve on pressure distribution and valve flow coefficient. International Society of Automation (ISA) recommends locations for measuring pressure drop of the valve to determine its flow coefficient. This paper presents the comparison of the pressures at different locations along with the upstream and the downstream of the valve with the values at recommended positions by the ISA standard. The results show that in partially filled pipe flow, the discrepancies in pressure between different measurement locations in the valve downstream are significant at valve openings less than 30%. The aerated flow induces the oscillation in pressure and flow rate, which leads to the fluctuation in the flow coefficient of the valve. The flow coefficients have a linear relationship with the Reynolds number. For the same increase of Reynolds number, the flow coefficients grow faster with larger valve openings and level off at the opening of 50%.

气泡夹带是一种会显着降低管道系统中液体运动效率的现象。在本研究中，通过可视化研究和压力振荡分析来解释具有 90% 水份流量的截止阀中的气泡形成机制。应用阴影图成像技术来说明透明阀内的不稳定流动。这有助于研究截止阀引起的气泡对压力分布和阀门流量系数的影响。国际自动化学会 (ISA) 推荐了测量阀门压降以确定其流量系数的位置。本文介绍了阀门上游和下游不同位置的压力与 ISA 标准推荐位置的压力值的比较。结果表明，在部分填充的管道流中，阀门下游不同测量位置之间的压力差异在阀门开度小于 30% 时非常显着。曝气流量引起压力和流量的振荡，从而导致阀门流量系数的波动。流量系数与雷诺数呈线性关系。对于雷诺数的相同增加，流量系数随着阀门开度的增大而增长得更快，并在开度为 50% 时趋于平稳。从而导致阀门流量系数的波动。流量系数与雷诺数呈线性关系。对于雷诺数的相同增加，流量系数随着阀门开度的增大而增长得更快，并在开度为 50% 时趋于平稳。从而导致阀门流量系数的波动。流量系数与雷诺数呈线性关系。对于雷诺数的相同增加，流量系数随着阀门开度的增大而增长得更快，并在开度为 50% 时趋于平稳。