Hydrostatic augmentation of a compliant foil hydrodynamic fluid film

Abstract

A system to hydrostatically augment the thrust load capacity of a bilateral compliant foil hydrodynamic fluid film thrust bearing for a turbomachine is disclosed. A plurality of channels and fixed orifices are provided in the bearing thrust plate to deliver and regulate compressor bleed air flow to the compressor side of the bilateral compliant foil hydrodynamic fluid film thrust bearing which includes additional channels and orifices to direct the bleed air against the bearing rotor thrust disk. After impinging on the rotor thrust disk, the bleed air flow exits the thrust bearing through a plurality of variable orifices comprised of the hydrodynamic thrust bearing elements which are controlled in their flow conductance by the axial position of the rotor thrust disk. The bleed air may then pass through the adjacent journal bearing which functions as a fixed orifice. The interaction of the fixed orifices and variable orifices establishes a pressure differential across and a net force applied to the bearing rotor thrust disk that varies as a function of the axial position of the bearing rotor thrust disk. Further, the bleed air from the bearing rotor thrust disk being delivered to the compliant foil hydrodynamic fluid film journal bearing of the turbomachine serves to cool the journal bearing.