CD70型高压旋塞阀结构强度及启闭特性分析

Analysis on Structural Strength and Open/Close Characteristic of CD70 High-pressure Cock Valve

高压旋塞阀是石油矿场固井和压裂作业时连接高压管汇的一个不可缺少的重要部件。为了优化现有CD70型旋塞阀的工作性能,对旋塞阀的结构强度与启闭特性进行了系统分析。研究结果表明:①在阀体密封相贯处过渡圆角半径增加的过程中,最大变形量在出口相贯处呈线性增大,最大值为0.1095 mm;最大等效应力在入口相贯处下部,最大值为598.77 MPa,小于材料42CrMo的屈服强度930 MPa。②当过渡圆角半径为5-7 mm时,阀体最大等效应力出现最小值,约为569 MPa,建议阀体密封相贯处过渡圆角半径取5-7 mm。③当阀的开度小于20%时,阀前的高压区和阀后的低压区范围显著增加,阀内开始出现剧烈的回流和漩涡现象,最大速度可达329.5 m/s,最大压力163 MPa;该最大压力已经超出了CD70型旋塞阀的额定设计压力104 MPa,呈现不安全因素;旋塞阀的关断过程要迅速,尽量缩短小开度的工作时间。研究结果可为旋塞阀的启闭控制系统设计和压裂泵的操纵规程制定提供参考依据。

The high-pressure cock valve is an indispensable and important component connecting the high-pressure manifold during cementing and fracturing operations in oil fields.In order to optimize the working performance of the existing CD70 cock valve,systematic analysis was conducted on the structural strength and open/close characteristic of it.The study results show that:①in the process of increasing the transitional round angle radius at the valve body seal intersection,the maximum deformation increases linearly at the outlet intersection,with a maximum value of 0.1095 mm;the maximum equivalent stress is at the lower part of the inlet intersection,with a maximum value of 598.77 MPa,which is less than the yield strength(930 MPa)of the material 42CrMo;②when the transitional round angle radius is 5-7 mm,the maximum equivalent stress of the valve body is minimum,about 569 MPa,and it is proposed to take the transitional round angle radius as 5-7 mm at the valve body seal intersection;and③when the opening of the valve is less than 20%,the range of the high-pressure area before the valve and the low-pressure area after the valve increases significantly,severe backflow and swirl phenomena begin to appear in the valve,the maximum velocity can reach 329.5 m/s,and the maximum pressure is 163 MPa,which has exceeded the rated design pressure(104 MPa)of CD70 cock valve,exhibiting unsafe factors;therefore,the shut-off process of the cock valve should be rapid to shorten the working time of small opening as far as possible.The study results provide reference for the design of the open/close control system of cock valve and the formulation of the working instruction of fracturing pump.