不同T型管汇液-固两相流颗粒冲蚀数值模拟

Numerical Simulation of Particle Erosion in Liquid-Solid Two-Phase Flow of Different T-Manifolds

目前对不同管汇处流场变化导致的冲蚀研究较少,基于计算流体动力学(CFD)仿真技术,研究了普通、球形、椭球形、梭形四种不同管汇T型管在颗粒流下的冲蚀行为。结果表明:当采用垂直管为入口管,水平支管为出口管的"一进两出"流动方式时,通过截取不同角度的流动切面发现椭球形管汇仅在45°~60°贴近管道壁面处产生一对二次流迪恩涡,其余管汇在30°~90°均有二次流产生。普通管汇的冲蚀主要发生在管汇与支管连接部位,其余管汇均发生在变径处,其中梭形管汇冲蚀最严重。通过改变流速、颗粒质量流量、颗粒密度、颗粒粒径,对比分析不同管汇的最大冲蚀速率变化规律,发现椭球形管汇最大冲蚀速率最低且变化幅度最小,具有较好的抗冲蚀特性。梭形管汇最大冲蚀速率最大且随影响因素变化幅度波动最大,因此生产中宜使用椭球形管汇,尽量避免使用球形管汇与梭形管汇。

At present,there are few researches on erosion caused by flow field changes at different manifolds. Based on the computational fluid dynamics( CFD) simulation technology,the erosion behavior of T-tubes with four different manifolds,i. e.,common,spherical,ellipsoidal and shuttle shaped,was studied in this paper. Results showed that when the vertical pipe was the inlet pipe,and the horizontal branch pipe was the outlet pipe,it was found by intercepting the flow sections of different angles that a pair of secondary flow Dean vortices were generated in the ellipsoidal manifold only at 45° to 60° close to the pipe wall,and the other manifolds had secondary flow in the range of 30° to 90°. The erosion of common manifold mainly occurred at the connection between manifold and branch pipe,and the other manifold occurred at the reducing diameter,among which shuttle manifold was the most serious. Besides,the maximum erosion rate of different manifolds was compared and analyzed by changing the flow rate,particle mass flow rate,particle density and particle size. It was found that the maximum erosion rate of ellipsoidal manifold was the lowest and the variation range of maximum erosion rate was the smallest,which had good erosion resistance. The maximum erosion rate of shuttle manifold was the largest and fluctuated with the influence factors to the maximum. Therefore,ellipsoid manifold should be used in production,while spherical manifold and shuttle manifold should be avoided as far as possible.