Hydrodynamic Characteristics of Cylindrical Spiral Grooves for Pump Annular Seals

Abstract

The hydrodynamic characteristics of pump annular seals are closely related to the internal flow characteristics and the pump operation stability. Previous studies of annular seals texture focus on damp rather than stiffness. Here a new spiral groove texture on cylindrical surface of annular seals is proposed. Based on the N-S equations, CFD method considering cavitation is used to simulate the internal flow of the spiral groove annular seals. Eccentricity is ensured by the moving mesh technology. The flow characteristics are studied, and comparatively analyzed with that of the smooth annular seals. Results show that: the spiral groove can generate the dynamic pressure effect and the pumping effect. Obvious changes in the pressure field appear. With eccentricity, the spiral groove can respectively enhance the stiffness, reset force and reduce the offset angle, which indicates that the spiral groove is helpful to acquire better rotor concentricity. The spiral groove also reduces the leakage and has little impact on the frictional torque. The above results demonstrate that the spiral groove is beneficial to improve the hydrodynamic characteristics of the annular seals and the concentricity of the rotor, which also reduces friction and wear.