气固两相流下球阀磨损特性研究

Research on erosion characteristics of ball valve under gas- solid two- phase flow

旋塞球阀是钻柱内防喷系统中的关键设备,在气固两相流下球阀易受磨损而失效,并造成严重的井喷事故。为此,将计算流体动力学理论与冲蚀磨损理论相结合,运用FLUENT软件对球阀壁面在气固两相流下的磨损分布情况进行研究,并进一步分析了球阀结构参数对于球阀壁面磨损的影响规律。结果表明:当气固两相流流经球阀时,固体颗粒会与气流分离,并在壁面上产生三处磨损集中区;随着球阀开度的减小,球阀壁面磨损量会急剧增大,且阀球内通道壁面上的磨损集中区由块状逐步转化为带状,而球阀出口处的磨损集中区则会逐渐向下移动;球阀流道直径的减小也会使得壁面磨损量增加,但磨损集中区的分布基本不变。研究结果可为进一步优化球阀流道结构以减轻其壁面磨损提供理论依据。

Ball valve is an important equipment in blowout prevention system within drill string, and the erosion of ball valve under gas-solid two-phase flow could result in its failure, which may cause serious blowout accident. So a mathematic model of gas-solid two-phase flow and erosion for ball valve was established based on the combining of computational fluid dynamics theory and erosion theory. The erosion situation of ball valve wall under gas-solid twophase flow was studied by using FLUENT software, and the effects of valve structure parameters and particle characteristics on erosion in the wall were further analyzed. The results showed that during the gas-solid two-phase flow process in the ball valve, solid particles will separate from gas flow and there are three main concentrating areas of erosion on the wall. With the decrease of ball valve opening, the erosion quantity increases sharply, the concentra- ting area located in valve flow channel wall experiences the transition from block to band, and the region near the valve outlet moves downward. In addition, reducing flow channel diameter also makes the increase of erosion quantity, but the distribution of concentrating areas remains basically unchanged. The study results can be a theoretical foundation for further study on improving flow channel structure of ball valve to reduce the wall erosion.