超(超)临界蒸汽疏水阀内部空化模拟

Numerical Study of Cavitation Flows in Ultra-supercritical Steam Trap

针对超(超)临界高温高压蒸汽疏水阀,将空化模型和混合两相流模型相结合,应用标准k-ε湍流模型,对疏水阀内部空化流动进行数值模拟。根据模拟结果,预测了疏水阀内部空化的发生与发展情况,并研究了不同开度、不同入口压力及不同密封面角度对内部空化流动的影响。同时进行了疏水阀防空化研究。结果表明,该计算可有效模拟疏水阀内部空化流动情况;随着开度的增加,空化先出现在阀座处,然后慢慢发展,在阀底部流道中形成了大量空化流动;随着进口压力的增大,空化程度越大,区域越大,延续越长;阀芯与阀座密封面角度为45°时,阀座处空化强度最低,区域最少;加入三级套筒与均流罩,有效抑制了阀内部空化的发生与发展。

Internal cavitation flow was numerically simulated in the ultra-supercritical steam trap by combining cavitation model and twophase flow model and using the standard k- ε model. The occurrence and development of internal cavitation in the valve were predicted and internal cavitation flow of the valve was studied under these conditions of different openings,different inlet pressures,different angles of sealing surface. Meanwhile,the anti-cavitation of the trap was studied. The results showed that the cavitation flow is well predicted. With the increase of opening the cavitation appears at the valve seat,developing gradually,finally a large number of cavitation form at valve bottom near wall. With the rise of inlet pressure,the cavitation intensify. When the angle of sealing surface becomes 45 degree,cavitation at the valve seat becomes lowest. Installing three-stage sleeve can restrain the occurrence and development of cavitation effectively.