双阀芯先导笼式调节阀的设计仿真与试验

Design Simulation and Experiment of Double Spool Pilot Cage Control Valve

为解决高温高压工况下调节阀的不平衡力及密封力难以达到所需泄漏等级的问题,设计了一种大阀芯和小阀芯分段配合工作、充分利用阀前介质压力增加阀座密封力的双阀芯先导笼式调节阀。文中给出了调节阀的不平衡力计算公式、流量方程,分析了其流量特性,并对阀内流体的流动进行了仿真,分析了流体流过调节阀后的压力损失;对大阀芯内腔进行了流体流动仿真,分析了阀前压力、内腔温度以及密封力的变化;对大、小阀芯进行了运动仿真,分析了执行器驱动力、阀芯轴向合力和大阀芯速度的变化。常温介质阀体耐压试验和阀座泄漏量试验结果表明,阀体均无可见泄漏和变形,泄漏量设定为10滴/min时,3次实测泄漏量分别为1、1和2滴/min。高温介质阀座泄漏量试验结果表明,泄漏量设定为1.275 mL/min时,250℃高温水蒸气的3次实测泄漏量分别为0.11、0.11和0.13 mL/min,300℃高温水蒸气的3次实测泄漏量分别为0.19、0.19和0.22 mL/min,实测泄漏量均小于设定值。文中提出的双阀芯先导笼式结构增强了调节阀的密封力,阀体耐压强度和阀座密封性能均满足使用要求。

Aiming at the problem that the unbalanced force and sealing force under high-temperature and high-pressure conditions are difficult to reach the required leakage level,a double spool pilot cage type control valve was designed,in which a large spool and a small spool work together in sections and the medium pressure in front of the valve is fully utilized to increase the sealing force of the valve seat.Then,the calculation equation of unbalanced force,the flow equation and the flow characteristics of the valve were analyzed,the fluid flow was simulated,and the pressure loss after the fluid flows through the control valve was analyzed.Moreover,the fluid flow in the inner cavity of the large valve spool was simulated,and the pressure before the valve,the temperature in the inner cavity as well as the sealing force was ana‐lyzed.The motion simulation of large and small spools was also carried out,and the driving force of the actuator,the axial resultant force of the valve spindle and the speed of the large spool were all discussed.The results of valve body’s pressure-tight test and valve seat’s leakage test of normal-temperature medium show that there is no visible leakage and deformation in the valve body;and that the measured leakages of three tests are respectively 1,1 and 2 drops per minute when the set leakage is 10 drops per minute.In addition,the results of valve seat’s leakage test of high-temperature medium show that,when the set leakage is 1.275 mL/min,the measured leakages of three tests for 250℃high-temperature steam are respectively 0.11,0.11 and 0.13 mL/min,while those for 300℃high-temperature steam are respectively 0.19,0.19 and 0.22 mL/min,finding that all the measured leakages are less than the set ones.The double valve spool pilot cage structure proposed in this paper enhances the sealing force of the regulating valve,and,the pressure strength of the valve body and the sealing performance of the valve seat both meet the use requirements.