Performance Analysis of Worn Misaligned 4-Lobe Multirecess Hybrid Journal Bearing System Compensated With Orifice Restrictor

Owing to the fast technological developments, the operating conditions of the machines are becoming very stringent, exact and more demanding. Various journal bearing designs have been developed to prevent the undesired effect of bearing whirl. An example of a successful design is the four-lobe multirecess journal bearing. The bearing which having four curved segments that referred to as four lobes is the four-lobe multirecess journal bearing. Further, as the 4-lobe journal bearing is expected to run over a number of cycles during its lifetime, it is subjected to several start/stop operations. These transient periods causes the bearing bush to wear out between the recesses and significantly affects the bearing performance. The modified Reynolds equation governing the flow of lubricant in the clearance space of bearing have been solved including the combined effects of three aspects, the worn effect, the misalignment angle and offset factors, using an iterative scheme based on FEM and Newton-Raphson method. The simulated results have been presented for a wide range of offset factor δ, wear depth parameter, journal misalignment factors (φ, Ψ) and external load. The simulated results suggests that it is an imperative to account for the effect of wear along with misalignment of journal in order to predict the performance of the bearing accurately. Further, it has been observed that in general as the value of offset factor increases the static and dynamic performance of the 4-lobe four pocket worn misaligned hybrid journal bearing compensated with orifice restrictor is clearly affected as compared to similar four pocket unworn aligned hybrid circular journal bearing. Further the bearing having offset factor δ = 1.2 improves the stability due to increase in the bearing stiffness and reduced magnitude of the cross-stiffness components.