关键词: 仿生设计;干气密封;稳定性;统计学;模糊数学

Abstract: Based on statistical method and gas lubrication theory, the correlation mathematical models of outline constructional feature of a bird wing and face groove feature of a dry gas seal (DGS) are established, and the film pressure controlling equation of a DGS is set up. The membership grades and their calculation expressions used to define face groove geometrical feature of a DGS are presented based on fuzzy mathematics, and DGSs are classified according to the membership grades. The gas film pressure control equations are resolved by use of finite difference method, and the gas film stiffness of a DGS is obtained. The correlation between the constructional feature parameters of bird wing outlines and flight speed and the correlation between face groove geometric parameters and operational stability of a DGS at different speeds are comparatively analyzed. Results show that the correlations between the geometric constructional feature parameters of bird wing outlines or face grooves and their flight speeds or operational speeds are in moderate degree. That is to say long wings give a bird stability, and long narrow wings give a bird more stability at high flight speeds, and long grooves give a DGS stability, and long narrow grooves give a DGS more stability at high operational speeds, correspondingly. Results also reveal that the relationship between a bird biological model and a DGS engineering model exists exactly. The feasibility of bionic design of face groove based on the geometric characteristics of bird wing outlines is demonstrated. The important theory basis is provided for the bionic design of a DGS.

Key words: bionic design;dry gas seal;stability;statistics;fuzzy mathematics