旋塞阀结构流道开度推导及其冲蚀速度分析

Flow channel openness deduction and erosion velocity analysis of cock valve

根据自行设计的钻井旋塞阀结构尺寸及其工作原理,建立了旋塞阀内流体通道过流面积变化几何结构模型,推导出旋塞阀转角与其开度的定量数学关系,给出了φ88.9 mm(31/2英寸)和φ127 mm(5英寸)旋塞阀转角与开度变化的关系曲线。当旋塞阀旋转某一角度时,可直观地在曲线上查出相应的开度,为旋塞阀开度的调节提供了可操作的经验公式。建立了旋塞阀流体通道的计算流体动力学计算CFD模型,得到了开度与阀体内壁流体最大冲蚀速度的关系曲线以及拟合公式。研究结果表明:开度越小阀心内的冲刷速度越高,对于提高阀心的寿命越不利,在旋塞阀的开启过程中,应该尽量避开长时间小开度状态,对阀心下游的阀座应采用耐冲蚀材料,以便延长其使用寿命。

According to the structural dimensions and operating mechanism of cock valve during the drilling,the variation geometric model of open area of flowing channel inside the cock valve is established and the quantitative mathematic relationship between the rotating angle and the openness of the cock valve is deducted,and moreover,the relationship curves of the rotating angle and the openness of cock valves of φ88.9 mm and φ127 mm are provided respectively.When the cock valve is rotated at a certain angle,the related openness can be indicated visually on the curves,thus providing an operational experience formula for adjusting the openness of the cock valve.The CFD model of the flowing channel is established and the relationship curve and matching formula of the openness and the maximum erosion velocity of valve inner wall are obtained.The study result shows that the smaller the openness is,the higher the erosion velocity inside the valve core is,which is detrimental to increasing the valve core life.Thus,during the openning of the cock valve,the long-time small openness should be avoided.The downstream valve seat of the valve core should be made of anti-erosion material for the purpose of extending its service life.