带浮升力垫片的指式封严浮升力特性的数值研究

Numerical Simulation on Lifting-force Characteristics of Finger Seal with Lifting-pads

对带直板式浮升力垫片的指式封严的浮升力特性进行数值分析,探讨转子表面线速度、封严间隙和进出口压差对浮升力垫片下表面的压力分布及浮升力和浮升力系数的影响。研究的封严结构由两层封严片(每层周向有72个指)组成,计算时将包含一个完整的浮升力垫片和其相邻间隙的三维扇区模型作为计算域,并将封严片组处理为多孔介质。研究结果表明:进出口压差越大,浮升力越大;浮升力随封严间隙的增大而减小;转子表面线速度增大,浮升力缓慢增大;浮升力系数随进出口压差的增大而减小;浮升力系数随封严间隙的增大而减小;转子表面线速度增大,浮升力系数减小,封严间隙越小这种趋势越明显。

The lifting-force characteristics of finger seal with flat lifting-pad were analyzed by numerical simulation,and the effects on pressure distribution of the lower surface of lifting-pads,lifting-force and lifting-force coefficient by the rotor speed,clearance of finger seal and pressure drop were investigated.The seal structure was consisted of two slice layers with 72 fingers per layer around its circumference,which were treated as the porous medium,and the three-dimensional （3-D）computation model included one lifting-pad and its nearby clearance.The research results indicate that the lifting-force is increased with the increase of pressure drop,and decreased with the increase of seal clearance,and increased slowly with the increase of rotor speed.The lifting-force coefficient is decreased with the increase of pressure drop,and decreased with the increase of seal clearance.Along with the increase of rotor speed,the lifting-force coefficient is de-creased,especially when the seal clearance is smaller.