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严重段塞流形成时,空气-水立管系统的压力和管内瞬时流量等参数大幅波动,不仅对下游设备造成冲击,而且容易导致管道剧烈振动等危害,准确计算严重段塞流瞬态流动参数是评估其危害的基础。基于气体、液体连续性方程与混合动量方程建立严重段塞流瞬态数学模型,详述数值积分方法,对立管试验装置中的严重段塞流现象进行数值模拟,并对模拟结果进行了验证。数值积分中,采用向后欧拉格式进行预报,梯形法校正;采用变时间步长以提高计算效率且保证精度;开展室内试验,并将严重段塞流循环周期、立管底部压力的试验结果与模拟结果进行了对比;将气、液流速和含气率等瞬态流动参数的模拟值与Fluent软件的计算结果进行了对比。结果表明:该数学模型和数值方法能够较好地计算典型严重段塞流的瞬态流动参数,有利于严重段塞流危害的准确评估。
During the formation of serious slug flow, the pressure of air-water riser system and the instantaneous flow rate in pipe fluctuate greatly, not only impact the downstream equipment, but also lead to the serious vibration of pipeline and other hazards, and accurately calculate the transient flow parameters of slug flow It is the basis for assessing its harm. Based on gas, liquid continuity equation and mixed momentum equation, a transient mathematical model of slug flow was established. The numerical integral method was introduced in detail. Numerical simulation of severe slugging phenomenon was carried out and the simulation results were verified. In the numerical integration, the backward Eulerian prediction and trapezoidal correction were adopted. The time-varying step was adopted to improve the calculation efficiency and ensure the accuracy. The indoor test was carried out and the results of serious slug-flow circulation period and riser bottom pressure Compared with the simulation results, the simulation results of transient flow parameters such as gas, liquid flow rate and gas content were compared with those of Fluent software. The results show that the mathematical model and numerical method can well calculate the transient flow parameters of a typical serious slug flow, which is favorable for the accurate assessment of the serious slugging slump flow.