Dynamic analysis of liquid annular seals with herringbone grooves on the rotor based on perturbation method

Annular seals have significant effects on the hydraulic and rotordynamic performances turbomachinery. In this paper, an analysis method for calculating the leakage rate and dynamic characterisitcs of liquid annular seals with herringbone grooves on the rotor is proposed and verified. Leakage flow rates and dynamic characteristics of the model seals under different operating conditions are theoretically analyzed and compared to those of the plain and spiral-grooved seals of the same size. Besides, the influence of geometric parameters such as spiral angle and the lengths of the constituent parts on the sealing and rotordynamic coefficients of seals with herringbone grooves are also discussed in this paper. The results show that seals with herringbone grooves have better sealing performance, while providing bigger support actions and better damping characteristics than the other two seal types under the same operating conditions. The seal geometric parameters including spiral angle, the lengths of the constituent parts and the clearance value have great influence on the dynamic characteristics of seals with herringbone grooves.