大流量旁通节流空化现象数值模拟对比分析

Comparative Analysis on Numerical Simulation of Cavitation Phenomenon of Large Flow Bypass Throttle

利用FLUENT多相流模型中的混合模型对大流量给水旁通节流空化现象进行了数值仿真对比分析,结果表明随着给水旁通管内介质流量的增加节流孔板后高温给水的空化现象越严重;当给水旁通管内介质流动达到某一临界值时节流孔板后高温给水几乎全部空化;多级节流孔板会显著降低高温给水节流空化的程度,同时3级节流孔板会明显增加给水旁通管路的阻力,3级节流孔板的阻力是1片节流孔板的2.5倍;随着管内压力的波动高温给水与水蒸气之间出现了瞬间的相互转化,这一转化过程造成了给水管路内壁的剥蚀及给水管路振动。

The mixed model of fluent multiphase flow model is used to simulate and analyze the cavitation phenomenon of large flow bypass throttling. The results show that the cavitation phenomenon of high temperature feed water is more serious with the increase of medium flow rate in the bypass pipe. When the medium flow in the bypass pipe reaches a certain critical value, the high temperature water supply after the orifice plate will almost be cavitating. The multi-stage orifice will significantly reduce the cavitation degree of high temperature feed water. At the same time, the multi-stage orifice will obviously increase the resistance of feed water bypass pipeline, and the resistance of the three-stage orifice is 2.5 times of that of one orifice. With the fluctuation of the pressure in the pipe, there is an instantaneous transformation between the high temperature water supply and the water vapor, which causes the erosion of the inner wall of the water supply pipe and the vibration of the water supply pipe.