The Performance of Hybrid Journal Bearing under Extreme Operating Conditions

Abstract

Fluid film bearing (FFB) performance is limited to normal operating conditions i.e. at moderate load and rotating speed. At extreme operating conditions like: high load and low speed FFBs do not perform well as contact between journal and bearing-surfaces occurs which results in bearing wear. To deal with these extreme conditions, a hybrid bearing (FFB + Halbach magnetic bearing) is proposed. The load capacity of hybrid bearing is estimated as vector summation of forces exerted due to fluid film lubrication as well as due to magnetic repulsion. In the present manuscript the load capacity of Halbach magnetic (HM) arrangement is estimated by summing the individual forces due to the rotor and stator magnets in axial, radial and perpendicular directions. To exemplify the proposed hybrid bearing arrangement, a case study of sugar mill top half bearing subjected to “high load (>1.5MN) and low rotating speed (5 rpm)” is considered. The results of hybrid bearing show far better performance of hybrid bearing compared to the FFB.