天然气井井下定压节流阀数值模拟及结构优化

Numerical Simulation and Structure Optimization of A Down-hole Throttling Valve of Constant Pressure for Gas Well

针对目前节流阀存在无法根据需要自动改变节流嘴尺寸等问题,利用ANSYS对一种新型天然气井井下定压节流阀进数值模拟,该节流阀可以根据节流阀入口压力的变化调节节流阀的开度,以保证节流阀出口压力基本保持在设计压力值范围不变,分析了节流阀在正常工作压力范围内、不同开度时,节流阀节流过程中的压力、速度和温度变化,仿真结果和理论计算结果相符;通过节流阀在气固两相流时的冲蚀磨损情况分析,表明在节流阀阀芯锥面冲蚀磨损最为严重,最大冲蚀率为4.413×10-7kg/(m2·s)。最后,基于前面分析结果对节流阀的阀芯和阀座进行结构优化,优化结果表明当节流阀阀座倾角β=10°时,阀芯冲蚀率最小;并对阀芯锥面进行氮化处理增强其耐磨性。

In view of the current throttle valve can＇t be automatically changed according to the need to change the size of the nozzle and other issues,a new type of natural gas well down-hole constant pressure throttle valve is simulated using ANSYS,the down-hole throttle valve can control the throttle opening size automatically according to the change of inlet pressure,which makes sure that the outlet pressure of throttle valve is basically in the designed area. The pressure,velocity and temperature of the throttle valve of the throttle valve are analyzed under the normal operating pressure range and different opening size,the simulation results are consistent with the theoretical calculation ones. Through analyzing the erosion of valve core and valve seat in two phase flow gas-solid,the results show that throttle valve core cone erosion wear is the most serious,the maximum erosion rate was 4. 413 × 10^-7 kg/（ m^2·s）. Finally,based on the numerical simulation results,the throttle valve core and valve seat structure are optimized,the optimization results demonstrate that when the throttle valve seat angle is set to β = 10°,the valve core erosion rate is the minimal.