Numerical investigation on the static performance of aerostatic journal bearings with different pocket shapes by the finite-element method

Abstract

In this work, to improve the static behavior of aerostatic journal bearings, we examine the effect of pockets with different shapes, including the square, rectangular 1, rectangular 2, and circular, manufactured on the surface of the aerostatic journal bearing. The effects of the pocket shapes, pocket area $\overline{S}$ , eccentricity ratio ɛ, orifice diameter d_f, average gas film thickness h₀, and misalignment angles ${\phi }_x$ and ${\phi }_y$ on the static performance are investigated using simulations. The Reynolds equation is solved by the finite-element method in this work. Simulations reveal that the pocket area $\overline{S}$ , eccentricity ratio ɛ, gas film thickness h₀, orifice diameter d_f, and misalignment angles ${\phi }_x$ and ${\phi }_y$ have a significant influence on the load force F and the stiffness K. In general, rectangular 2 pocket bearings are found to perform somewhat better than bearings with other pocket shapes, with the pocket depth set to one-half of h₀, when the pocket area $\overline{S}$ varies from one-twelfth to one. The pocket area $\overline{S}$ should be set according to the average gas film thickness h₀ and the orifice diameter d_f to achieve a better static performance for the bearings. For bearings operated with misalignment angles ${\phi }_x$ and ${\phi }_y$ , different pocket areas $\overline{S}$ should be set according to the pocket shapes for the optimal design.