نبذة مختصرة : This study investigates the performance of an air foil bearing with particular focus on the fluid-solid interactions through the use of Computational Fluid Dynamics and Finite Element Analysis software. The effect of top foil deflection is investigated by varying the stiffness of the bump foil and the number of bumps on the foil. Results suggest that the range of stiffnesses investigated; $500N/mm$, $2500N/mm$ and $5000N/mm$, did not show any significant alterations to the magnitude or distribution of radial deflections in the top foil. It is found that varying the number of bumps in a bump foil has a significant effect on the magnitude of displacement. For a foil bearing design with an eccentricity ratio of 0.5, a bump stiffness of $500N/mm$, the maximum deflection for 18, 32 and 70 bumps is $2.1269 \mu m$, $12.762\mu m$ and $4.1582\mu m$. Too many and too few bumps results in increased stiffness of the top foil. The location of maximum deflection in the top foil corresponds to the circumferential location of the region of maximum negative gauge pressure for a design with 18 bumps, $500N/mm$ stiffness, and eccentricity ratio 0.5. The behaviour of the top foil suggests that the bump foil controls the deflection of the top foil in the positive radial direction only, due to the nature of the bump foil design.
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