Bionic Design Of Multi-Path-Grooved Face Of A Mid-and-Low Speed Dry Gas Seal Based On Bird Wings

A common dry gas seal (DGS) with spiral grooves will meet with the problems of lower opening force, poor stability when it operates at mid-and-low speeds or during the period of start-up or stop, therefore its application maybe restricted. Theoretical and experimental investigations of a new bionic groove DGS were carried out based on the multi-path characteristic of flying-bird wings with the aim of improving the opening behavior of a spiral groove DGS at mid-and-low speeds.First, a theoretical analysis model of a bionic multi-path groove DGS was established based on gas lubrication theory and birds structures. The geometric parameters of a DGS with bionic-groove face were defined when the spiral groove line was set as the bionic groove wall profile line.Then, the hydrostatic performance of a bionic multi-path groove DGS was analyzed. The effect of geometric parameters on sealing performance of such a new DGS was studied. The geometric parameters were optimized for high ratio of stiffness to leakage of a DGS with twin-path spiral-grooves. Further, the influence of channel numbers on sealing performance was discussed. The comparisons between a DGS with common spiral grooves and a DGS with bionic multi-path grooves were made and showed that the latter had the better combination performance, such as lower leakage rate and higher level of gas film stifihess.Finally, an experimental and theoretical comparison study was carried out among the DGSs with spiral grooves, twin-path spiral grooves, spiral and annular grooves and spiral and twin-path spiral grooves. It was showed that the twin-path groove has the lowest leakage rate, and which verified the correctness of the theory.This paper further confirmed the reasonableness of bionic by applying bionic concept to development of groove-types of a DGS. Based on theoretical and experimental investigations on the new-type of bionic grooves, the value of this paper was important to the further study of a DGS. The results were meaningful for designing a DGS at mid-and-low speeds.