This research describes the dynamic behavior of an isolated slug driven by pressurized air in a voided line with an end orifice. A three-dimensional (3D) computational-fluid-dynamics (CFD) model is used to simulate the rapid propulsion and impact at the orifice for given slug length and driving air pressure, and is validated against experimental data. New mechanisms are observed: (i) the driving air pressure at the slug tail decreases with the slug motion; (ii) when the slug arrives at the orifice, the air fraction is almost one hundred percent in the most upstream part of the pipe, then it attenuates rapidly until an invariant eighty percent is achieved with a constant mass shedding rate; (iii) the velocity distribution in the radial direction of the cross-section at the midpoint of the slug length evolves from uniform to trapezoidal and then to logarithmic during slug movement; (iv) the initial vertical slug front changes its shape due to air intrusion at the top of the slug front; (v) the slug’s acceleration decreases first and then increases under the combined effects of its decreasing mass, nonlinear attenuation of the driving pressure, and increasing skin friction; (vi) the slug length has a constant rate of decrease.

这项研究描述了由加压空气驱动的隔离段塞在带有端孔的空隙管线中的动态行为。三维 (3D) 计算流体动力学 (CFD) 模型用于模拟给定段塞长度和驱动气压下孔口处的快速推进和冲击，并根据实验数据进行验证。观察到新机制： ( i ) 段塞尾部的驱动气压随着段塞运动而降低；( ii )当段塞到达孔口时，管道最上游部分的空气比例几乎为百分之一百，然后迅速衰减，直到达到恒定的百分之八十，质量脱落率恒定；(三) 段塞长度中点处截面径向速度分布在段塞运动过程中由均匀分布到梯形再到对数分布；( iv ) 初始垂直段塞前缘由于段塞前缘顶部的空气侵入而改变其形状；( v ) 段塞的加速度在其质量减小、驱动压力非线性衰减和皮肤摩擦增加的综合作用下先减小后增大；( vi ) 段塞长度有一个恒定的减少率。