摘要
建立湿蒸气凝结流动的双流体模型,考虑了湿蒸气汽液两相流动中相间速度滑移、耦合以及湍流扩散作用的影响。针对蒸汽透平叶栅中流动的湍流特性,在单相湍流计算中数值模拟精度相对良好的两方程SSTk-ω湍流模型基础上,参照颗粒湍能输运方程理论,推导建立了湿蒸气两相流动SSTk-ω-kp湍流模型,模型中引入了液相粘性、导热及扩散系数等拟流体概念。对一直列叶栅中存在自发凝结的湿蒸气流动进行了三维数值模拟,结果表明:与中心截面相比,端壁附近汽流首先出现大量凝结核,并较早恢复到平衡状态,由于涡系结构的存在使得沿叶高汽液两相叶栅出口马赫数之间存在一定差异。本文建立的模型提高了湿蒸气凝结流动三维数值模拟的精度,更好地揭示叶栅中凝结流动的相间作用。
A dual fluid model for wet-steam condensation flows was established with due consideration of such effects as inter-phase speed slip,coupling and diffusion of turbulent flows in wet-steam steam-liquid two-phase flows.In the light of the turbulent characteristics of flows in steam turbine cascades,derived and established was the SST k-ω-kp turbulent flow model of wet steam two-phase flow by consulting the conveyance equation theory of particle turbulent energy and on the basis of the turbulent flow model involving two equations SST k-ω,which have a relatively good numerical simulation accuracy in single-phase turbulent flow calculations.In the above model,introduced were several quasi-fluid conceptions,such as liquid-phase viscosity,heat conductivity and diffusion coefficient etc.On this basis,a three-dimensional numerical simulation was conducted of a wet steam flow of spontaneous condensation existing in a rectilinear cascade.It can be shown that compared with a central section,a large quantity of condensation nuclei first emerged from steam flows in the vicinity of the end walls and regained their balance state relatively early.There exists a certain difference among the mach numbers at the outlet of the steam-liquid two-phase flow cascade along the blade height due to the existence of a structure of vortex system.The model established by the authors can enhance the three-dimensional numerical simulation accuracy of wet steam condensation flows and better reveal the interphase function of condensation flows in a cascade.
出处
《热能动力工程》
CAS
CSCD
北大核心
2007年第4期367-370,共4页
Journal of Engineering for Thermal Energy and Power
基金
国家自然科学基金资助项目(50336050)
关键词
透平叶栅
湿蒸气
凝结流动
双流体模型
两相湍流模型
数值模拟
turbine cascade,wet steam,condensation flow,dual fluid model,two-phase turbulent flow model,numerical simulation
