Study on the Evolution of Sealing Performance during the Start-Up Process of Dynamic Pressure Seals Based on Three-Dimensional Fractal Functions

Abstract

A model based on a three-dimensional fractal function is developed and used in conjunction with experiments to analyze the evolutionary pattern of sealing performance during the start-up process of dynamic pressure seals, and the influence of end-face microscopic features on the evolution law is discussed. It is found that the opening state of the seal is divided into three stages: the non-opened stage, transition stage, and full-opened stage. The isotropic dimensions of the cavities have a coupling effect on the leakage, and they diminish as the speed increases. In order to enhance the sealing performance during start-up, it is suggested that the seal faces have a fractal dimension of 2.4 to 2.6, and a characteristic factor of less than 1 × 10−9 m.