An Investigation of Self-Acting Foil Bearings

Experimental results on the interior and the exit region film-thickness measurements of self-acting foil bearings are presented and discussed. These measurements were made with capacitive sensors and conductive foils. The measured and predicted values agree very well within the range of nondimensional parameters, h₀/R, from 10⁻⁴ to 10⁻³ and, T/μU, from 10⁵ to 10⁶. The agreement deviates for values beyond these ranges. Empirical expressions for predicting the constant and minimum film thickness applicable beyond these ranges are also presented. They are valid within the range of h₀/R from 5(10)⁻⁵ to 10⁻² and T/μU from 10⁴ to 10⁵. Growing sinusoidal film thickness in the exit region was also observed, measured, and checked with theoretical predictions.