The effectiveness of squeeze-film damper bearings supporting rigid rotors without a centralising spring

Abstract

A method has been devised for comparing the effectiveness of squeeze-film damper bearings of various configurations. The analysis in this report is limited to the case of rigid-rotors without parallel flexible supports, but is to be extended to the case of flexible rotors. The performance of squeeze-film damper bearings can be expressed in terms of three independent system parameters, B the bearing parameter ( μRL 3 mωc 3 ), W ̄ the gravity parameter ( W mcω 2 ) and U the unbalance ratio ( F u mcω 2 ). For a rigid rotor it would appear that the design of an effective squeeze-film damper bearing would require W ̄ to be less than 0·1, and B to be around 0·2. Also it is seen that for some range of the system parameters the effectiveness of the device increases with increasing unbalance ratio U. As an extension of the present investigation, it is shown that very small values of B produce unstable orbits or non-synchronous whirl components. Also, it is shown that the orbits and maximum transmitted forces produced by squeeze-film damper bearings with similar ratios of U W ̄ differ considerably, and that the determination of the performance of a squeeze-film damper bearing relies upon the absolute values of these two parameters.