Rapport II.3 Radial forces acting in gap seals of hydraulic pumps and turbines

In this paper the stiffness of gap seals will be discussed. Radial forces as they arise in gap seals with mainly axial flow have been investigated for the case of steady radial deflection of the rotor. Even the effects of entry losses, friction losses and the particularity of the exit losses, being different in circumferential direction are shown. The influence of these effects on the amount of the radial forces and finally the calculation of these radial forces - Lomakin effect - is shown. At least a comparison of calculated and measured critical speed of the isogyre pumpturbine - Power station Malta upperstage (Autriche) - is represented and the difference between estimated and calculated stiffness of the radial gap seels will be discussed.Hassler Peter. Rapport II.3 Radial forces acting in gap seals of hydraulic pumps and turbines. In: Machines hydrauliques. Conception et exploitation. Développements récents et Applications aux différents secteurs industriels. Vingtièmes journées de l'hydraulique. Lyon, 4-6 avril 1989. Tome 2, 1989