摘要
为揭示流场中粘性引起的边界层分离与自发凝结相互作用的机理,对缩放喷管和汽轮机叶栅中的自发凝结两相流动进行了数值模拟.气相采用N-S方程,液相凝结过程采用对多阶复合参数进行积分的方法求解.通过比较粘性流动和非粘性流动中液相参数分布的差异,分析了边界层分离和尾迹涡扰动与凝结相互作用的机理.结果表明:凝结的存在使得湿蒸汽流动中叶栅吸力面边界层的分离程度远大于过热蒸汽流动中的分离程度,边界层分离产生的损失不可忽视.对边界层分离和尾迹涡产生叶型损失的原因进行了分析,结果表明:尾迹涡的扰动作用使得成核过程发生了变化,且改变了水滴数和湿度的分布.
In order to reveal the mechanism of interaction of the boundary layer separation and spontaneous condensation caused by the viscous flow, the spontaneous condensation two-phase flow in converging/diverging nozzles and turbine cascade were numerically studied. The Navier - Stokes Viscous Equation was applied for the gas-phase, and the process of condensation was calculated by the quadrature method of multi-order composite parameters. The interaction mechanism of boundary layer separation and wake vortices with spontaneous nucleation was analyzed by comparing difference of liquid parameters distribution between viscous and inviscous flow. Results show that in wet steam flow, degree of boundary layer separation is far greater than that in superheated steam flow due to the existence of condensation, and the loss caused by boundary layer separation can＇t be neglected. Further, the impact of boundary layer separation and wake vortices on profile loss were analyzed. Results show that the process of nucleation is changed due to the disturbing of wake vortices, leading to different droplet number and wetness distributions.
出处
《动力工程》
CSCD
北大核心
2009年第8期752-756,共5页
Power Engineering
基金
国家自然科学基金资助项目(50676031)
关键词
湿蒸汽
两相流动
凝结
边界层分离
尾迹涡
叶型损失
数值模拟
wet steam
two-phase flow
eondensation
boundary layer separation
wake vortices
profile loss
numerical simulation
