The wear evolution mechanism of sliding bearing in aviation gear pump under boundary lubrication condition

Wearing is a key factor leading to failure of aviation fuel gear pumps. In order to study the boundary lubrication performance and wear evolution of sliding bearings under extreme working conditions of aviation fuel gear pumps, a finite difference method was used to establish a thermo-elasto-hydrodynamic (TEHD) model of sliding bearings that takes into account the rough surface contact effect. The oil film pressure, temperature, and surface contact pressure distribution under rough surface sliding contact were obtained, and the influence of rough surface texture on the lubrication flow field was analyzed. On the basis of considering the adhesive wear effect, the Archard model is introduced to establish the adhesive wear thermo-elasto-hydrodynamic (AW-TEHD) model to solve the wear distribution and surface roughness conditions of the bearing surface under different speed and load conditions. The research results show that as the bearing speed increases from 60% rated speed to 120% rated speed, the surface wear of the bush gradually increases, increasing by about 78.3%, while the area of wear remains basically unchanged; Among the typical operating conditions of the sliding bearings in fuel gear pumps, the wear depth is highest under low-speed and heavy-load conditions, which is 139% of the rated load wear depth at the same speed. The wear depth under high-speed and heavy-load conditions is reduced by about 58.7% compared to the rated load condition. The influence of speed on wear depth under rated load is relatively small, and almost no wear occurs.