Investigation on backflow phenomenon in the aerostatic journal bearing

In this work, the backflow phenomenon exhibited in the gas journal bearings is investigated. The effect of operational parameters such as eccentricity ratio e, axial velocity of the bearing v(z), misalignment angles on the backflow behavior, and load force and axial friction force of the bearing are studied numerically. The differential transformation method and finite difference method are utilized to solve the dimensionless Reynolds equations required in the analysis. The performance parameters such as pressure distribution, gas flow rate, load force, and axial friction force are examined in the numerical simulations. The investigation reveals that when the bearing is operated in normal working zone, the load force F increases significantly with an increase in eccentricity e; however, F may only increase slightly when the bearing operates in the backflow zone. It is suggested that the pressure P-s should be set greater than 5.0, P-c smaller than or equal to 3.0 to avoid the backflow behavior. The axial friction force is largely determined by the pressure, and increases as pressure P-c increases.