超超临界火电机组高温减压调节阀空蚀问题分析及结构优化

摘要

针对超超临界火电机组高温减压调节阀(361阀)普遍存在的空蚀问题，结合合川电站361阀在实际使用中出现的三通底板空蚀现象，基于两相空化流动控制方程，采用Fluent软件对该阀的内部流场进行了数值分析.数值模拟结果表明：空蚀现象是引起这类阀门失效的一个重要原因，这与实际失效分析结果基本吻合，从而验证了该数值分析方法的合理性；根据这一结果，采取在三通处加长尾管的措施后，三通拐弯处底板的压力降低了18．09％，流体速度降低50．45％，拐弯处含汽量明显减少，涡流现象明显减弱，解决了空蚀问题，提高了阀门的使用寿命.%Cavitation problems occur frequently on high temperature pressure reducing valves (361valves) used in ultra supercritical units.Combining with the serious cavitation on the based board of three links of the 361 valve used in Hechuan Power Station,the flow field inside the 361 valve was numerically simulated by Fluent software,on the basis of two-phase cavitation flowing equations.The results show cavitation is an important reason for failure of this kind of valve,which is basically in accordance with the actual failure case.Thus the rationality of this numerical analysis method is verified.According to the simulation results, after the tail pipe was lengthened at the T piece,the pressure at bending point of the T piece decreased by 18.09% and the fluid speed reduced by 50.45%.The steam content at the bending point the T piece dropped significantly and the vortex phenomenon weakened dramatically,so the valve's service life was pro-longed.