1. A fluid expansion device into which a fluid is adapted to enter at a first pressure, through which the fluid is adapted to flow, and from which the fluid is adapted to exit at a second pressure that is less than the first pressure, the fluid expansion device comprising:
a stationary first member;
a stationary second member defining first and second surfaces and comprising at least one of a ring, a curved shell, and a plate, the first member abutting the first surface of the second member; and
a plurality of first acoustic resonators, each of the first acoustic resonators comprising:
a first opening extending
from the first surface defined by the second member, and into the second member;
and
a plurality of second openings, each of the second openings extending
from the second surface, and
to the first opening;
the first member capping the end of the first opening opposing the second openings;
wherein one or more of the first acoustic resonators attenuate acoustic energy generated during the flow of the fluid.
2. The fluid expansion device of claim 1 wherein the first member comprises at least one of an inlet, an outlet, and an annular section.
3. The fluid expansion device of claim 2 wherein the first member comprises the annular section;
wherein the second member comprises the ring, the ring defining the first and second surfaces, one of the ring and the annular section extending circumferentially about the other so that the annular section abuts the first surface of the ring and thereby caps the respective ends of the first openings opposing the respective pluralities of second openings;
and
wherein the fluid expansion device further comprises:
a plurality of first blades extending from the second surface of the ring, each of the first blades defining a leading edge and a trailing edge;
a rotatable wheel; and
a plurality of second blades extending from the rotatable wheel;
the first blades being stationary and directing the fluid to the second blades to thereby impel the wheel to rotate.
4. The fluid expansion device of claim 3 wherein at least one first acoustic resonator in
the plurality of first acoustic resonators is positioned
between each pair of adjacent first blades in the plurality of first blades, and relatively proximate the respective trailing edges of the adjacent first blades.
5. The fluid expansion device of claim 4 further comprising:
another annular section;
another ring defining third and fourth surfaces, one of the another annular section and the another ring extending circumferentially about the other so that the another annular section abuts the third surface of the another ring;
a plurality of second acoustic resonators, each of the second acoustic resonators comprising:
a third opening extending
from the third surface defined by the another ring, and
into the another ring;
and
a plurality of fourth openings, each of the fourth openings extending
from the fourth surface, and
to the third opening;
the another annular section capping the end of the third opening opposing the fourth openings;
wherein one or more of the second acoustic resonators attenuate acoustic energy generated during the flow of the fluid;
wherein the first blades extend between the rings; and
wherein at least one second acoustic resonator in the plurality of second acoustic resonators is positioned
between each pair of adjacent first blades in the plurality of first blades, and
relatively proximate the respective trailing edges of the adjacent first blades.
6. The fluid expansion device of claim 3 wherein each of the first blades defines a blade surface having a curvature; and
wherein the plurality of first acoustic resonators comprises a plurality of first groups of the first acoustic resonators, each of the first groups comprising:
a first series of the first acoustic resonators formed in the ring
between each pair of adjacent first blades in the plurality of first blades, and
along a path that generally conforms to at least the curvature of the blade surface defined by one of the first blades in the pair of adjacent first blades.
7. The fluid expansion device of claim 6 wherein at least one first acoustic resonator in each of the first series of the first acoustic resonators is positioned at each of the following locations:
relatively proximate the respective leading edges of the adjacent first blades;
relatively proximate the respective trailing edges of the adjacent first blades;
and
between the respective leading and trailing edges of the adjacent first blades;
the locations generally conforming to at least the curvature of the blade surface defined by the one of the first blades in the pair of adjacent first blades.
8. The fluid expansion device of claim 7 further comprising:
another annular section;
another ring defining third and fourth surfaces, one of the another annular section and the another ring extending circumferentially about the other so that the another annular section abuts the third surface of the another ring;
a plurality of second acoustic resonators, comprising a plurality of second groups of the second acoustic resonators, each of the second groups comprising:
a second series of the second acoustic resonators formed in the another ring;
each of the second acoustic resonators comprising:
a third opening extending
from the third surface defined by the another ring, and
into the another ring;
and
a plurality of fourth openings, each of the fourth openings extending
from the fourth surface, and
to the third opening;
the another annular section capping the end of the third opening opposing the fourth openings;
wherein one or more of the second acoustic resonators attenuate acoustic energy generated during the flow of the fluid;
wherein the first blades extend between the rings; and
wherein at least one second acoustic resonator in each of the second series of the second acoustic resonators is positioned at each of the following locations:
relatively proximate the respective leading edges of the adjacent first blades;
relatively proximate the respective trailing edges of the adjacent first blades;
and
between the respective leading and trailing edges of the adjacent first blades;
the locations generally conforming to at least the curvature of the blade surface defined by the one of the first blades in the pair of adjacent first blades.
9. The fluid expansion device of claim 2 wherein the first member comprises one of the inlet and the outlet, the one of the inlet and the outlet defining a curved inside surface; and
wherein the second member comprises the curved shell defining the first and second surfaces, the one of the inlet and the outlet extending circumferentially about the curved shell so that the curved inside surface abuts the first surface of the curved shell and thereby caps the respective ends of the first openings opposing the respective pluralities of second openings.
10. A steam turbine through which a fluid is adapted to flow, the steam turbine comprising:
a stationary first annular section;
a stationary first ring defining first and second surfaces, one of the first ring and the first annular section extending circumferentially about the other so that the first annular section abuts the first surface of the first ring;
a plurality of first acoustic resonators, each of the first acoustic resonators comprising:
a first opening extending
from the first surface defined by the first ring, and
into the first ring;
and
a plurality of second openings, each of the second openings extending
from the second surface, and
to the first opening;
the first annular section capping the end of the first opening opposing the second openings;
wherein one or more of the first acoustic resonators attenuate acoustic energy generated during the flow of the fluid;
a plurality of first blades extending from the second surface of the ring, each of the first blades defining a leading edge and a trailing edge;
a rotatable wheel;
a plurality of second blades extending from the rotatable wheel, wherein the first blades are stationary and direct the fluid to the second blades to thereby impel the wheel to rotate;
a stationary second annular section;
a stationary second ring defining third and fourth surfaces, one of the second annular section and the second ring extending circumferentially about the other so that the second annular section abuts the third surface of the second ring;
a plurality of second acoustic resonators, each of the second acoustic resonators comprising:
a third opening extending
from the third surface defined by the second ring, and
into the second ring;
and
a plurality of fourth openings, each of the fourth openings extending
from the fourth surface, and
to the third opening;
the second annular section capping the end of the third opening opposing the fourth openings;
wherein one or more of the second acoustic resonators attenuate acoustic energy generated during the flow of the fluid;
wherein the first blades extend between the rings;
wherein at least one first acoustic resonator in the plurality of first acoustic resonators is positioned between each pair of adjacent first blades in the plurality of first blades;
and
wherein at least one second acoustic resonator in the plurality of second acoustic resonators is positioned between each pair of adjacent first blades in the plurality of first blades.
11. A method comprising:
providing a fluid expansion device;
introducing a fluid into the fluid expansion device;
expanding the fluid using the fluid expansion device after introducing the fluid into the fluid expansion device;
generating acoustic energy during expanding the fluid; and
attenuating the acoustic energy generated during expanding the fluid, comprising:
providing a first member defining first and second surfaces;
extending a plurality of first openings from the first surface of the first member and into the first member;
extending a plurality of second openings from the second surface of the first member and to each of the first openings; and
capping the respective ends of the first openings opposing the respective pluralities of second openings with a surface defined by fluid expansion device.
12. The method of claim 11 wherein the first member comprises a ring; and
wherein expanding the fluid using the fluid expansion device comprises:
providing a rotatable wheel within the fluid expansion device; and
impelling the wheel to rotate, comprising:
extending a plurality of first blades from the wheel; and
directing the fluid to the first blades, comprising:
extending a plurality of second blades from the ring, each of the second blades defining a leading edge and a trailing edge; and
permitting the fluid to flow between adjacent pairs of the second blades.
13. The method of claim 12 wherein at least one plurality of second openings is positioned
between each pair of adjacent second blades in the plurality of second blades, and
relatively proximate the respective trailing edges of the adjacent second blades.
14. The method of claim 12 wherein each of the second blades defines a blade surface having a curvature; and
wherein a group of pluralities of second openings is positioned in a series between each pair of adjacent second blades in the plurality of second blades, the pluralities of second openings in the series being positioned along a path that generally conforms to at least the curvature of the blade surface defined by one of the second blades in the pair of adjacent second blades.
15. The method of claim 11 wherein the fluid expansion device comprises an inlet via which the fluid is introduced into the fluid expansion device, and an outlet via which the fluid exits the fluid expansion device; and
wherein the first member comprises a curved shell defining the first and second surfaces, one of the inlet and the outlet extending circumferentially about the curved shell so that the one of the inlet and the outlet abuts the first surface of the curved shell and thereby caps the respective ends of the first openings opposing the respective pluralities of second openings.
16. A system comprising:
a fluid expansion device;
means for expanding a fluid using the fluid expansion device after introducing the fluid into the fluid expansion device;
means for attenuating acoustic energy generated during expanding the fluid, comprising:
a first member defining first and second surfaces;
a plurality of first openings extending from the first surface of the first member and into the first member;
a plurality of second openings extending from the second surface of the first member and to each of the first openings; and
means for capping the respective ends of the first openings opposing the respective pluralities of second openings with a surface defined by the fluid expansion device.
17. The system of claim 16 wherein the first member comprises a ring; and
wherein means for expanding the fluid using the fluid expansion device comprises:
means for providing a rotatable wheel within the fluid expansion device; and
means for impelling the wheel to rotate, comprising:
means for extending a plurality of first blades from the wheel; and
means for directing the fluid to the first blades, comprising:
means for extending a plurality of second blades from the ring, each of the second blades defining a leading edge and a trailing edge; and
means for permitting the fluid to flow between adjacent pairs of the second blades.
18. The system of claim 17 wherein at least one plurality of second openings is positioned
between each pair of adjacent second blades in the plurality of second blades, and
relatively proximate the respective trailing edges of the adjacent second blades.
19. The system of claim 17 wherein each of the second blades defines a blade surface having a curvature; and
wherein a group of pluralities of second openings is positioned in a series between each pair of adjacent second blades in the plurality of second blades, the pluralities of second openings in the series being positioned along a path that generally conforms to at least the curvature of the blade surface defined by one of the second blades in the pair of adjacent second blades.
20. The system of claim 16 wherein the fluid expansion device comprises an inlet via which the fluid is introduced into the fluid expansion device, and an outlet via which the fluid exits the fluid expansion device; and
wherein the first member comprises a curved shell defining the first and second surfaces, one of the inlet and the outlet extending circumferentially about the curved shell so that the one of the inlet and the outlet abuts the first surface of the curved shell and thereby caps the respective ends of the first openings opposing the respective pluralities of second openings.
21. A system comprising:
a fluid expansion device; and
a noise-attenuating array positioned proximate a source of generated noise in the fluid expansion device.
22. The system of claim 21 wherein the fluid expansion device comprises a steam turbine.
23. The system of claim 21 wherein the array comprises a plurality of acoustic resonators.
24. The system of claim 22 wherein the array further comprises a member defining first and second surfaces, the first surface abutting a portion of the fluid expansion device; and
wherein each of the acoustic resonators comprises:
a first opening extending from the first surface of the member and into the member; and
a plurality of second openings, each of the second openings extending from the second surface of the member and to the first opening;
wherein the abutment between the first surface of the member and the portion of the fluid expansion device caps the end of the first opening opposing the plurality of the second openings.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for stabilizing disturbances in electric grid currents in a wind turbine energized electric grid, comprising:
coupling the stator of a wind driven doubly fed induction generator to the grid;
coupling the rotor of the doubly fed induction generator to the grid by way of a line side converter, the line side converter comprising a plurality of current conducting electric switches; and,
providing the current conducting switches of the line side converter with sufficient current carrying capacity to produce frequency support and increased grid stabilizing currents while providing frequency support and requiring lesser amounts of grid stabilizing currents from the stator of the doubly fed induction generator thereby allowing for increased power producing stator current during disturbances in the electric grid.
2. The method of claim 1, further comprising coupling the rotor of the doubly fed induction generator to the line side converter by way of a rotor side converter and a direct current link, the rotor side converter comprising a plurality of current conducting electric switches.
3. The method of claim 2, further comprising:
coupling a dynamic brake across the direct current link; and,
controlling the dynamic brake in dependence on the voltage level across the direct current link.
4. The method of claim 3, wherein coupling a dynamic brake comprises coupling a series connected switch and a dissipative device across the direct current link.
5. The method of claim 4, wherein coupling a series connected solid state switch and a resistor across the direct current link.
6. The method of claim 5, wherein controlling the dynamic brake comprises modulating a signal applied to the solid state switch in accordance with voltage variations across the direct current link.
7. The method of claim 2, wherein the current carrying capacity provided for the line side converter switches is at least as great as the current carrying capacity provided for the rotor side converter switches.
8. The method of claim 2, wherein the plurality of current conducting electric switches in the line side converter and the plurality of current conducting electric switches in the rotor side converter are provided as insulated gate bipolar transistors.
9. The method of claim 5, wherein coupling a series connected solid state switch comprises coupling an insulated gate bipolar transistors.
10. Apparatus for stabilizing disturbances in electric grid currents in a wind turbine energized electric grid, comprising:
a wind driven doubly fed induction generator having a stator and a rotor, wherein said stator is coupled to said electric grid; and,
a line side converter, the line side converter comprising a plurality of current conducting electric switches configured to couple the rotor of said doubly fed induction generator to said grid;
wherein the current conducting switches are provided with sufficient current carrying capacity to produce frequency support and increased grid stabilizing currents while providing frequency support and requiring lesser amounts of grid stabilizing currents from the stator of the doubly fed induction generator thereby allowing for increased power producing stator current during disturbances in the electric grid.
11. The apparatus of claim 10, further comprising:
a rotor side converter, said rotor side converter comprising a plurality of current conducting electric switches; and,
a direct current link coupling said rotor side converter to said line side converter.
12. The apparatus of claim 11, further comprising:
a dynamic brake coupled across said direct current link; and,
a controller responsive to a voltage level across said direct current link coupled to the dynamic brake.
13. The apparatus of claim 12, wherein said dynamic brake comprises a series connected switch and a dissipative device coupled across the direct current link.
14. The apparatus of claim 13, wherein said series connected switch is a solid state switch and the dissipative device is a resistor.
15. The apparatus of claim 14, wherein said controller is configured to modulate a signal applied to the solid state switch in accordance with voltage variations across the direct current link.
16. The apparatus of claim 11, wherein the current carrying capacity provided for the line side converter switches is the same as the current carrying capacity provided for the rotor side converter switches.
17. The apparatus of claim 11, wherein said plurality of current conducting electric switches in the line side converter and said plurality of current conducting electric switches in the rotor side converter are insulated gate bipolar transistors.
18. The apparatus of claim 14, wherein said series connected solid state switch comprises an insulated gate bipolar transistors.