Suppression of Rubbing in Rotating Machines by Lemon-Type Bearing

Rotor-to-stator or rotor-to-guide rubbing in rotating machines is a serious problem. The contact (rub and impact) between the rotor and the guide creates an excessive vibration which may lead to permanent damage of the mechanical system. In the present work, the rubbing phenomenon between the rotor and the guide is investigated by simulation and experiment. Two different types of clearance bearings are implemented, which are based on circular and lemon-type guides. Rigorous mathematical models for the lemon-type guide as well as for the traditional circular clearance bearing are derived. Then, a Jeffcott rotor model is simulated for the investigation of the rubbing behavior for the two types of bearings. The numerical model is developed in matlab simulink. For different clearances and friction levels between rotor and guide, and several initial conditions, the rubbing phenomena are studied and evaluated. Finally, a comparison between experimental and simulation work is carried out to validate the overall scenarios in this research work. Results indicate that the lemon-type bearing can reduce the likelihood of sustained rubbing, compared with the circular clearance bearing, for the considered test cases.