We Claim:
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.
2. The bearing assembly in accordance with Claim 1, wherein
at least one of said damper assemblies comprises a hermetically sealed fluid-filled
damper.
3. The bearing assembly in accordance with Claim 2, wherein
said 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 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.
4. 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.
5. 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.
6. The bearing assembly in accordance with Claim 5, 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.
7. The bearing assembly in accordance with Claim 1, wherein
at least one of said bearing pads is fabricated from carbon graphite.
8. 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.
9. 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 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.
10. The turbomachine in accordance with Claim 9, wherein said
turbomachine is a non-oil lubricated turbomachine.
11. The turbomachine in accordance with Claim 9, wherein said
process gas comprises at least one of compressed air and combustion gases.
12. The turbomachine in accordance with Claim 9, wherein said
shaft has a mass of at least about 50 pounds.
13. The turbomachine in accordance with Claim 9, wherein each
of said bearing pad support assemblies comprises:
a spring assembly; and
a damper assembly.
14. The turbomachine in accordance with Claim 13, 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. 15. The turbomachine in accordance with Claim 9, wherein said
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 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.
16. 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; and
coupling the damper assemblies within the bearing housing. 17. The method in accordance with Claim 16, wherein providing
the plurality of bearing pad support assemblies comprises providing at least one
hermetically sealed fluid-filled damper, and wherein the method further comprises
coupling the hermetically sealed fluid-filled damper to a bearing pad such that
mechanical loads imparted to the bearing pad are transmitted to the hermetically
sealed fluid-filled damper.
18. The method in accordance with Claim 16, further comprising
coupling the bearing pads in fluid communication with a pressurized gas source.
19. The method in accordance with Claim 16, wherein providing a
plurality of bearing pads comprises providing at least one bearing pad fabricated
from carbon graphite.
20. The method in accordance with Claim 16, 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.