泵口环圆柱面螺旋槽造型的流体动力特性

Hydrodynamic characteristics of cylindrical spiral grooves modeling for pump annular seals

泵叶轮口环动力特性的改善可通过环形密封面造型来实现.为了改善其刚度特性,提出一种新的口环圆柱面螺旋槽造型方法,采用基于空化的CFD方法对口环间隙流动进行模拟计算,通过动网格技术来确保小环形间隙下的偏心量,研究了螺旋槽对口环流动特性的影响,并与光滑口环流动特性进行对比分析.结果表明:螺旋槽会产生动压效应和泵送效应,在槽台侧和槽坝侧尖角处分别产生低压区和高压区;偏心时,螺旋槽能增大口环间隙主刚度和支反力,降低偏位角,从而提高转子的对中性能;同时使泄漏量大幅降低,而使摩擦转矩略有增大;螺旋槽造型有利于提高口环的流体动力特性和转子对中性能,并减小口环的摩擦和磨损.

The dynamic properties of pump annular seals can be improved by modeling on the cylindrical sealing surface. To improve the stiffness characteristics,a new spiral grooves modeled on the cylindrical surface of annular seals was proposed. Considering cavitation the CFD method was used to simulate the internal flow of annular seals,and the small annular eccentricity was ensured by the moving mesh technology. The influence of spiral grooves on the flow characteristics was studied and comparatively analyzed with that of smooth annular seals. The results show that the spiral grooves can generate dynamic pressure effect and pumping effect. The low and the high pressure zones appear at the sharp corners of stair and dam side respectively. With eccentricity,the spiral grooves can enhance stiffness and reset force with reduced offset angle,which indicates that the spiral grooves is helpful to acquire better rotor concentricity. The spiral grooves can also obviously reduce the leakage and slightly increase the frictional torque. The spiral grooves is beneficial to improve the hydrodynamic characteristics of annular seals and the performance of rotor concentricity,which can also reduce the friction and wear.