Influence of radial labyrinth seal on pump performance

Abstract

Labyrinth seals have been used as non-contacting sealing devices for rotors such as on turbo machines. In recent years, an improvement of the sealing performance of labyrinth seals has been required due to the increasing pressure of turbo machines. In this paper, it is suggested that new type pump labyrinth seals (Radial labyrinth type) have high sealing performance on pump wear rings in the radial direction of fundamental labyrinth grooves seals. This study was carried out by CFD analysis. First, radial labyrinth seals were tested in an actual double suction pump. Subsequently, it became clear that pump radial labyrinth seals have an effect of increasing pump efficiency by reducing leakage compared to general plain wear ring seals. It was also confirmed by various experiments that the radial labyrinth seals have the effect of increasing pump suction specific speed. Furthermore, it was demonstrated that the rotor-dynamics coefficients of radial labyrinth seals are smaller than plain seals.