Influence of wear on the performance parameters of the rigid bore aerodynamic journal bearing

Rigid bore aerodynamic journal bearings are widely used in precision machinery, high-speed small turbomachinery, etc., to support and guide the motion of shafts. Due to several starts/stops of the machinery, these bearings may wear out in the service, and subsequently, their performance parameters (static and dynamic) may change. This paper presents the impact of wear on the performance of these bearings. The governing equations have been discretised using the FDM, and the pressure solution has been obtained using the Gauss-Seidel method with successive over-relaxation technique. The performance parameters have been plotted with respect to the eccentricity ratio varying in the range of 0.20 to 0.95. The results show that load capacity, attitude angle, friction force, stiffness, and damping coefficients decrease. The friction coefficient is enhanced with a maximum wear depth parameter rise under the same eccentricity ratio. Under constant load, the friction coefficient declines with a rise in wear, which highlights the potential benefit of wear. It has been found that the maximum wear depth parameter less than equal to (≤) 10% of bearing radial clearance slightly impacts the performance parameters, but a wear depth of more than that severely impacts the performance of the bearing.