Lubrificação ativa aplicada a mancais hibridos radiais

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The stability of rotating systems supported by multirecess hydrostatic journal bearings is closely reIated to the dynamic characteristics of the bearing lubricant fluid film. The instability problems arise with the increase of the machine rotational speed, due to the bearing damping reduction and the increase of the joW Ilal cross coupling effect. An increase in this stability reserve can be achieved by adapting active servo control systems on the conventional bearings; Fluid fiJmforces are generated in hydrostatic journal bearings mainly by two types of lubrication mechanisms: the hydrostatic lubrication in the bearing recesses and hydrodynanúc lubrication in the bearing lands, when operating in rotation. The combination of both lubrication mechanisms leads to hybrid journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hydraulic control systems, one refers to the active lubrication. The main objective in this work is the investigation of an active hybridjournal bearing (AHJB), combining computational fluid dynamics and control tecbniques. The main contribution of the present work is reIated to the feasibility of influencing the hybrid joumal bearing stiffuess and damping coefficients by controlling the fluid injection into opposed bearing recesses. One shows that is possible to reduce cross-coupling stiffuess and increase the direct damping coefficients by means of the active lubrication, what leads to rotor-bearing systems with Jarger threshold of stability. The active lubrication limitations and implementation capabilityare al so discussed, based on the hydraulic controller and rotor-bearing system characteristic behaviors

ASSUNTO(S)

lubrificação mancais vibração estabilidade

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