单钩波形板分离器内二次携带机理分析

摘要

The theory analysis and three-dimensional numerical simulations were carried out to study the re-entrainment mechanism in a single-hooked wave-plate separator under operating conditions .The Realizable k-εmodel was utilized to calculate the steam flow fields of the separator .The discrete phase model with eddy-interaction model was adopted to predict the trajectories of the droplets .The equations of the film motion were solved to obtain the film velocity and thickness distribution .Four potential regimes of secondary droplet formation were analyzed theoretically .The results show the possibili-ty of droplet breakup by aerodynamics and splashing by droplet impinging the film is low ,but higher than that of the cold conditions .The film exists mainly on the first two stages and thickens and moves downwards with increasing the steam velocity or wetness at the separator inlet . The film stripping and separation are proved to be the main reasons for the re-entrainment and unified with one discriminant .Compared with the film stripping ,the film separation at the peak of the hook occurs more easily .%通过理论分析与三维数值模拟研究了实际运行工况下单钩波形板分离器内二次携带机理.采用Realizable k-ε湍流模型对波形板内气相流场进行数值模拟,利用离散相模型结合涡交互模型对水滴运动进行计算,根据壁面水膜运动方程求解水膜的速度与厚度分布;依据理论分析,对可能形成二次水滴的4种方式进行判定.结果表明:波形板内发生气体动力造成的水滴破碎与水滴撞击水膜产生飞溅的可能性较低,但较冷态工况的可能性高;水膜主要集中在波形板的前两级,随入口蒸汽速度或湿度的增加,水膜增厚并向下游移动;将水膜剥落和水膜分离的判别式进行统一,并证实波形板二次携带主要由水膜的剥落和分离造成,且相较水膜剥落,钩峰处的水膜分离更易发生.