柔片式密封泄漏流动的数值仿真分析

针对柔片式密封的流场和密封性能及其影响因素进行研究,建立了密封区域流体动力学计算模型,对密封间隙内流场的速度、压力分布和泄漏量进行了计算,分析了工况和结构参数对泄漏量的影响趋势.分析表明:密封泄漏量随密封压差的增大呈线性增长趋势,而随转子转速的增加变化不大;柔片宽度由3mm增加至7mm,系统泄漏量降低了40%左右,而柔片长度由12mm增加至16mm,泄漏量仅增加8%左右;前/背板与柔片或转子间间距的增大将使泄漏量上升,且前板与转子间设计间距对泄漏量相对影响较大,随其增加,泄漏量最高可增加16%;柔片末端楔形区域对泄漏量及对转子作用力均产生影响. 

Numerical simulation and analysis of leaf seal leakage flow

Leakage flow field of leaf seal, seal performance and its influential factors were analyzed based on its structure feature,and fluid dynamics calculative model of sealing zone was built.The velocity,pressure distribution in sealing clearance and leakage were calculated,and the sealing performance with structure parameters in different working conditions was obtained.The result shows that the leakage increases linearly with the sealing pressure,and decreases slightly with the increase of rotor speed;leakage reduces by about 40% with the leaf width from 3mm to 7mm,while it increases by only about 8% with the leaf length from 12mm to 16mm.With the widening gap of the front/back cover plate to leaf or to rotor,the result is also different;the gap from upper cover plate to rotor has greater impact on leakage compared with lower cover plate, with the leakage up to 16%.Leakage and rotor force are also affected by different dip angles of the leaf end.