1989 年 55 巻 510 号 p. 317-322
The dynamic characteristics of annular seals for turbopumps have been experimentally investigated. In the experiment, fluid forces acting on the seal were measured for various parameters such as the preswirl velocity, the pressure difference between inlet and outlet of the seal, the whirling amplitude, and the ratio of whirling speed to spinning speed of the rotor. Influence of these parameters on the dynamic characteristics was investigated from the experimental results. As a result, the dynamic characteristics are largely affected by the preswirl velocity. The positive preswirl velocity plays an instabilizing role, and the negative preswirl velocity plays a stabilizing role in the rotor system. The axial flow through the seal also gives a stabilizing effect to the rotor system.