Journal bearing assemblies and methods of assembling same

1. A journal bearing assembly comprising:

a bearing housing comprising a radial outer wall;

a plurality of bearing pads mounted within said bearing housing, said bearing pads comprising at least one of a gas permeable porous media and an array of gas delivery holes; and

a plurality of bearing pad support assemblies radially interposed between said bearing pads and said radial outer wall, each said bearing pad support assembly comprising:

a spring assembly; and

a damper assembly comprising a hermetically sealed fluid-filled damper, wherein the hermetically sealed fluid-filled damper comprises:

a sealed damper housing comprising a body having a cavity and a resistive flow path defined therein, the cavity and the resistive flow path being filled with a viscous fluid;

a plunger disposed within the cavity, said plunger separating the cavity into a first control volume and a second control volume, wherein the resistive flow path provides fluid communication between the first and second control volumes; and

a load transferring member coupled to said plunger, said load transferring member configured to transmit mechanical loads imparted on said bearing pads to said plunger.

2. The bearing assembly in accordance with claim 1 , wherein at least one of said spring assemblies comprises two springs integrally formed with said bearing housing, said springs having an “S”-shaped cross-section.

3. The bearing assembly in accordance with claim 1 , wherein said bearing housing comprises a radial inner wall adapted to receive said bearing pads such that said radial inner wall is interposed between said bearing pads and said damper assemblies, said radial inner wall configured to transmit mechanical loads from said bearing pads to said bearing pad support assemblies.

4. The bearing assembly in accordance with claim 3 , wherein said bearing housing comprises a plurality of gas delivery ports extending from said radial outer wall towards said radial inner wall, each said gas delivery port in fluid communication with a bearing pad.

5. The bearing assembly in accordance with claim 1 , wherein at least one of said bearing pads is fabricated from carbon graphite.

6. The bearing assembly in accordance with claim 1 , wherein said plurality of bearing pads define an annular inner bearing surface configured to support a rotatable shaft.

7. A turbomachine comprising:

a casing defining a process chamber;

a rotor assembly comprising a rotatable shaft positioned within the process chamber; and

a journal bearing assembly supporting said shaft, said bearing assembly comprising:

a bearing housing;

a plurality of bearing pads mounted within said bearing housing, said bearing pads comprising at least one of a gas permeable porous media and an array of gas delivery holes; and

a plurality of bearing pad support assemblies radially interposed between said bearing pads and said bearing housing, at least one of said bearing pad support assemblies comprising a damper assembly comprising a hermetically sealed fluid-filled damper assembly, said bearing assembly configured to receive a process gas from the process chamber and transmit the process gas to said bearing pads to provide lubrication between said shaft and said bearing pads, wherein the hermetically sealed fluid-filled damper comprises:

a sealed damper housing comprising a body having a cavity and a resistive flow path defined therein, the cavity and the resistive flow path being filled with a viscous fluid;

a plunger disposed within said cavity, said plunger separating the cavity into a first control volume and a second control volume, wherein the resistive flow path provides fluid communication between the first and second control volumes; and

a loading member coupled to said plunger, said loading member configured to transmit mechanical loads imparted on said bearing pads to said plunger.

8. The turbomachine in accordance with claim 7 , wherein said turbomachine is a non-oil lubricated turbomachine.

9. The turbomachine in accordance with claim 7 , wherein said process gas comprises at least one of compressed air and combustion gases.

10. The turbomachine in accordance with claim 7 , wherein said shaft has a mass of at least about 50 pounds.

11. The turbomachine in accordance with claim 7 , wherein each of said bearing pad support assemblies further comprises:

a spring assembly.

12. The turbomachine in accordance with claim 11 , wherein at least one of said spring assemblies comprises two springs integrally formed with said bearing housing, said springs having an “S”-shaped cross-section.

13. A method of assembling a journal bearing assembly, said method comprising:

providing a bearing housing including a radial inner wall and a radial outer wall;

providing a plurality of bearing pads including at least one of a gas permeable porous media and an array of gas delivery holes;

coupling the plurality of bearing pads along the radial inner wall of the bearing housing;

providing a plurality of bearing pad support assemblies, each of the bearing pad support assemblies including a spring assembly and a damper assembly comprising at least one hermetically sealed fluid-filled damper, wherein the at least one hermetically sealed fluid-filled damper is coupled to a bearing pad such that mechanical loads imparted to the bearing pad are transmitted to the at least one hermetically sealed fluid-filled damper; and

coupling the damper assemblies within the bearing housing.

14. The method in accordance with claim 13 , further comprising coupling the bearing pads in fluid communication with a pressurized gas source.

15. The method in accordance with claim 13 , wherein providing a plurality of bearing pads comprises providing at least one bearing pad fabricated from carbon graphite.

16. The method in accordance with claim 13 , wherein providing a plurality of bearing pad support assemblies comprises providing two springs integrally formed with the bearing housing, the springs having an “S”-shaped cross-section.