Effect of a circumferential feeding groove in a short squeeze-film damper

Abstract

The present work investigates the effects of a circumferential feeding groove in a short squeeze-film damper (SFD) on fluid force and dynamic responses of a rotor in SFDs. The groove is taken as a special damper to analyse the effects. The dynamic performance of the SFD with the groove is attributed to two film lands, the special damper and their interactions. From this viewpoint, the fluid force in the groove is analysed on the basis of the linearized Navier-Stokes equations. Analysis of the fluid force in film lands is carried out using a simplified Navier-Stokes equation to include fluid inertia. Then, from the continuity condition and the Navier-Stokes equation, fluid interactions between the groove and the film lands are investigated. The two analyses are combined together by investigation of the interactions, resulting in new models for fluid force predictions. The new models are compared with published work. The comparisons show that the new models give better predictions and correction with experimental data than traditional theory. The new models provide a significant improvement on the results obtained by traditional theory, especially for tangential force. Based on the new models, the present work also analyses effects of the groove on the unbalance response and stability of a rigid rotor in SFDs. Comparisons with published work show that the groove affects the unbalance response of a rotor system. The effects of the groove on dynamic coefficients of SFD cause the response of the rotor system to be stable for some range of system parameters, being different from the results of traditional theory. This is important for designing a rotor system.