Apparatuses including a rotor group and methods of damping the apparatuses

Abstract

An apparatus includes a rotor group rotatable within the apparatus and a bearing assembly supporting the rotor group. A support structure supports the bearing assembly and is fixed in the apparatus. The support structure includes a support housing, an anisotropic support that engages the bearing assembly and the support housing, and a squeeze film cavity that is defined between the anisotropic support and the support housing. A damper fluid supply line is in fluid communication with the squeeze film cavity. A fluid interruption device is disposed in the damper fluid supply line. A method of damping the apparatus includes supplying fluid under pressure to the squeeze film cavity through the damper fluid supply line. Upon surpassing a predetermined value of a variable correlated to rotational speed of the rotor group, the fluid flow to the squeeze film cavity is interrupted with the fluid interruption device.

What is claimed is: 
     
         1 . An apparatus comprising:
 a rotor group that is rotatable within the apparatus;   a bearing assembly that supports the rotor group;   a support structure that supports the bearing assembly and that is fixed in the apparatus, wherein the support structure includes:
 a support housing; 
 an anisotropic support engaging the bearing assembly and the support housing; and 
 a squeeze film cavity defined between the anisotropic support and the support housing; 
   a damper fluid supply line in fluid communication with the squeeze film cavity for independently providing a fluid to the squeeze film cavity; and   a fluid interruption device disposed in the damper fluid supply line for interrupting a fluid flow to the squeeze film cavity.   
     
     
         2 . The apparatus of  claim 1 , wherein the fluid interruption device halts the fluid flow to the squeeze film cavity upon surpassing a predetermined value of a variable correlated to rotational speed of the rotor group. 
     
     
         3 . The apparatus of  claim 1 , wherein the fluid interruption device comprises a pressure regulating valve. 
     
     
         4 . The apparatus of  claim 1 , wherein the fluid interruption device is controlled by an engine control system. 
     
     
         5 . The apparatus of  claim 1 , wherein a fluid reservoir is in fluid communication with the damper fluid supply line for providing the fluid to the damper fluid supply line. 
     
     
         6 . The apparatus of  claim 5 , wherein a main supply line is disposed between and in fluid communication with the fluid reservoir and the damper fluid supply line, and wherein the damper fluid supply line is split from the main supply line. 
     
     
         7 . The apparatus of  claim 6 , wherein a bearing fluid supply line is further split from the main supply line for independently providing the fluid to the bearing assembly. 
     
     
         8 . The apparatus of  claim 6 , further comprising a fluid pump in fluid communication with the main supply line for pressurizing the fluid in the main supply line. 
     
     
         9 . The apparatus of  claim 1 , wherein the anisotropic support comprises at least two rings connected by asymmetrically-arranged beams. 
     
     
         10 . The apparatus of  claim 9 , wherein the squeeze film cavity is further defined between one of the at least two rings of the anisotropic support and the support housing, 
     
     
         11 . A method of damping vibration in an apparatus, the method comprising the steps of:
 providing the apparatus comprising a rotor group that is rotatable within the apparatus, a bearing assembly that supports the rotor group, a support structure that supports the bearing assembly and that is fixed in the apparatus, wherein the support structure includes a support housing, an anisotropic support engaging the bearing assembly and the support housing, and a squeeze film cavity defined between the anisotropic support and the support housing, and wherein the apparatus further comprises a damper fluid supply line in fluid communication with the squeeze film cavity for independently providing a fluid to the squeeze film cavity, and a fluid interruption device disposed in the damper fluid supply line;   supplying fluid under pressure to the squeeze film cavity through the damper fluid supply line; and   interrupting a fluid flow to the squeeze film cavity with the fluid interruption device upon surpassing a predetermined value of a variable correlated to rotational speed of the rotor group.   
     
     
         12 . The method of  claim 11 , wherein the variable is further defined as fluid pressure in the damper fluid supply line, and wherein the fluid flow to the squeeze film cavity is interrupted by the fluid interruption device upon surpassing a predetermined value of fluid pressure in the damper fluid supply line. 
     
     
         13 . The method of  claim 11 , wherein the variable is further defined as rotational speed of the rotor group, and wherein the fluid flow to the squeeze film cavity is interrupted by the fluid interruption device upon surpassing a predetermined value of rotational speed of the rotor group. 
     
     
         14 . The method of  claim 11 , wherein the predetermined value of the variable corresponds to a value of the variable at least at a critical speed of the rotor group, and wherein the fluid flow to the squeeze film cavity is interrupted upon surpassing the predetermined value of the variable that is at least at the critical speed of the rotor group. 
     
     
         15 . The method of  claim 14 , wherein the predetermined value of the variable corresponds to a value of the variable in a range of from a value of the variable at the critical speed of the rotor group to a value of the variable at  20  percent above a rigid body critical speed of the rotor group. 
     
     
         16 . The method of  claim 11 , wherein interrupting the fluid flow to the squeeze film cavity comprises halting the fluid flow to the squeeze film cavity upon surpassing the predetermined value of the variable correlated to rotational speed of the rotor group. 
     
     
         17 . The method of  claim 11 , wherein a fluid reservoir is in fluid communication with the damper fluid supply line through a main supply line disposed between and in fluid communication with the fluid reservoir and the damper fluid supply line, wherein the damper fluid supply line is split from the main supply line, and wherein supplying fluid under pressure to the squeeze film cavity comprises pressurizing the fluid in the main supply line. 
     
     
         18 . The method of  claim 17 , wherein a bearing fluid supply line is further split from the main supply line for independently providing the fluid to the bearing assembly, and wherein a fluid flow to the bearing assembly is uninterrupted when the fluid flow to the squeeze film cavity is interrupted. 
     
     
         19 . The method of  claim 11 , wherein bearing loads are decreased by at least 30% upon interrupting the fluid flow to the squeeze film cavity. 
     
     
         20 . An apparatus comprising:
 a rotor group that is rotatable within the apparatus;   a bearing assembly that supports the rotor group;   a support structure that supports the bearing assembly and that is fixed in the apparatus, wherein the support structure includes:
 a support housing; 
 an anisotropic support comprising at least two rings connected by asymmetrically-arranged beams and engaging the bearing assembly and the support housing; and 
 a squeeze film cavity defined between the anisotropic support and the support housing; 
   a damper fluid supply line in fluid communication with the squeeze film cavity for independently providing a fluid to the squeeze film cavity;   a fluid reservoir in fluid communication with the damper fluid supply line for providing the fluid to the damper fluid supply line;   a main supply line disposed between and in fluid communication with the fluid reservoir and the damper fluid supply line, and wherein the damper fluid supply line is split from the main supply line;   a bearing fluid supply line further split from the main supply line for independently providing the fluid to the bearing assembly; and   a fluid interruption device disposed in the damper fluid supply line and controlled by an engine control system for interrupting a fluid flow to the squeeze film cavity, wherein a fluid flow to the bearing assembly is uninterrupted when the fluid flow to the squeeze film cavity is interrupted by the fluid interruption device.