Abstract
An acoustically dampened gas turbine engine (10) having a gas turbine engine combustor (12) with an acoustic damping resonator system is disclosed. The acoustic damping resonator system (14) may be formed from one or more resonators (16) formed from a resonator housing (18) positioned within the gas turbine engine combustor (12) at an outer housing (20) forming a combustor basket (22) and extending circumferentially within the combustor (12). In at least one embodiment, the resonator housing (18) may include one or more resonator chambers (18) that provide enhanced cooling with reduced risk of cracking and other damage. The resonator housing (18) may include resonator exhaust orifices (26) that are positioned closer to an area of maximum temperature within the combustor (12), thereby enabling the resonator (16) to reduce the temperature gradient within the combustor (12). The resonator housing (18) may be sized and configured to reduce stress found in conventional systems by increasing distances between resonator exhaust orifices (26) and between resonator inlet impingement orifices (30), among others.
Claims
1-15. (canceled)
16. An acoustic damping resonator system for a combustor of a turbine engine, comprising: at least one resonator housing defining at least one inner channel with an inner surface and an outer surface on an opposite side of the at least one resonator housing from the inner surface; at least one resonator chamber extending radially outward from the at least one resonator housing, wherein the at least one resonator chamber includes at least one resonator inlet impingement orifice in an outer wall of the at least one resonator chamber and at least one resonator exhaust orifice extending through the at least one resonator housing; and wherein the at least one resonator exhaust orifice extending through the at least one resonator housing is offset axially upstream to place the at least one resonator exhaust orifice closer to an area of maximum temperature within the combustor.
17. The acoustic damping resonator system of claim 16, wherein the at least one resonator exhaust orifice comprises a plurality of resonator exhaust orifices that are positioned closer to an upstream wall of the at least one resonator chamber than a downstream wall of the at least one resonator chamber.
18. The acoustic damping resonator system of claim 17, wherein the plurality of resonator exhaust orifices are separated from each other a distance equal to at least one and one half times a diameter of a smallest diameter of the plurality of resonator exhaust orifices.
19. The acoustic damping resonator system of claim 17, wherein the plurality of resonator exhaust orifices are separated from each other a distance equal to at least two times a diameter of a smallest diameter of the plurality of resonator exhaust orifices.
20. The acoustic damping resonator system of claim 17, wherein the plurality of resonator exhaust orifices are collected into a pattern of an inverted triangle with a point of the triangle pointed downstream.
21. The acoustic damping resonator system of claim 17, wherein the plurality of resonator exhaust orifices are collected into a pattern of a rectangle.
22. The acoustic damping resonator system of claim 17, wherein the at least one resonator inlet impingement orifice comprises a plurality of resonator inlet impingement orifices that are offset from the plurality of resonator exhaust orifices such that at least one of the plurality of resonator inlet impingement orifices is radially aligned with the at least one resonator housing in which the plurality of resonator exhaust orifices are positioned such that cooling fluids flowing into the at least one resonator chamber impinge on the at least one resonator housing.
23. The acoustic damping resonator system of claim 22, wherein the plurality of resonator inlet impingement orifices form fewer rows as rows formed by the plurality of resonator exhaust orifices, and wherein the rows formed by the plurality of resonator inlet impingement orifices extend circumferentially and are aligned radially between rows of the plurality of resonator exhaust orifices beginning with a first upstream row of resonator exhaust orifices and moving downstream.
24. The acoustic damping resonator system of claim 23, wherein the plurality of resonator inlet impingement orifices form a first row that has one fewer orifices than a first row of resonator exhaust orifices and wherein the plurality of resonator inlet impingement orifices form a second row downstream from the first row of resonator inlet impingement orifices, whereby the second row of resonator inlet impingement orifices has two fewer orifices than a second row of resonator exhaust orifices.
25. The acoustic damping resonator system of claim 24, wherein the second row of inlet impingement orifices skips a position in a middle of the second row of resonator exhaust orifices.
26. The acoustic damping resonator system of claim 23, wherein the plurality of resonator inlet impingement orifices form a first row that has one fewer orifices than a first row of resonator exhaust orifices and wherein the plurality of resonator inlet impingement orifices form a second row downstream from the first row of resonator inlet impingement orifices, whereby the second row of resonator inlet impingement orifices has at least an additional orifice than the first row of inlet impingement orifices and the second row of resonator exhaust orifices has at least an additional orifice than the first row of resonator exhaust orifices.
27. The acoustic damping resonator system of claim 22, wherein the plurality of inlet impingement orifices are separated from each other a distance equal to at least one and one half times a diameter of a smallest diameter of the plurality of inlet impingement orifices.
28. The acoustic damping resonator system of claim 22, wherein the plurality of inlet impingement orifices are separated from each other a distance equal to at least two times a diameter of a smallest diameter of the plurality of inlet impingement orifices.
29. The acoustic damping resonator system of claim 16, wherein a ratio of distance between the outer wall of the at least one resonator chamber and the at least one resonator housing to a diameter of the at least one resonator inlet impingement orifice is between about seven and about four.
30. The acoustic damping resonator system of claim 16, wherein the outer wall is sized in thickness such that a ratio of a length of the at least one resonator inlet impingement orifice extending radially inward to a diameter of the at least one resonator inlet impingement orifice is greater than one.
31. An acoustic damping resonator system for a combustor of a turbine engine, comprising: at least one resonator housing defining at least one inner channel with an inner surface and an outer surface on an opposite side of the at least one resonator housing from the inner surface; at least one resonator chamber extending radially outward from the at least one resonator housing, wherein the at least one resonator chamber includes at least one resonator inlet impingement orifice in an outer wall of the at least one resonator chamber and at least one resonator exhaust orifice extending through the at least one resonator housing; wherein the at least one resonator exhaust orifice extending through the at least one resonator housing is offset axially upstream to place the at least one resonator exhaust orifice closer to an area of maximum temperature within the combustor; wherein the at least one resonator exhaust orifice comprises a plurality of resonator exhaust orifices that are positioned closer to an upstream wall of the at least one resonator chamber than a downstream wall of the at least one resonator chamber; and wherein the at least one resonator inlet impingement orifice comprises a plurality of resonator inlet impingement orifices that are offset from the plurality of resonator exhaust orifices such that at least one of the plurality of resonator inlet impingement orifices is radially aligned with the at least one resonator housing in which the plurality of resonator exhaust orifices are positioned such that cooling fluids flowing into the at least one resonator chamber impinge on the at least one resonator housing.
32. The acoustic damping resonator system of claim 31, wherein the plurality of resonator exhaust orifices are separated from each other a distance equal to at least two times a diameter of a smallest diameter of the plurality of resonator exhaust orifices.
33. The acoustic damping resonator system of claim 31, wherein the plurality of resonator inlet impingement orifices form half as many rows as rows formed by the plurality of resonator exhaust orifices, and wherein the rows formed by the plurality of resonator inlet impingement orifices extend circumferentially and are aligned radially between rows of the plurality of resonator exhaust orifices beginning with a first upstream row of resonator exhaust orifices and moving downstream.
34. The acoustic damping resonator system of claim 31, wherein the plurality of inlet impingement orifices are separated from each other a distance equal to at least two times a diameter of a smallest diameter of the plurality of inlet impingement orifices.
35. The acoustic damping resonator system of claim 31, wherein a ratio of distance between the outer wall of the at least one resonator chamber and the at least one resonator housing to a diameter of the at least one resonator inlet impingement orifice is between about seven and about four.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.
[0014] FIG. 1 is partial cross-sectional side view of a combustors positioned within gas turbine engines.
[0015] FIG. 2 is a cross-sectional side view of a combustor in the gas turbine engine taken as section line 2-2 in FIG. 1.
[0016] FIG. 3 is a perspective view of a combustor liner with an acoustic damping resonator system.
[0017] FIG. 4 is a schematic diagram of a combustor in the gas turbine engine with a conventional resonator.
[0018] FIG. 5 is a cross-sectional side view of a resonator of the acoustic damping resonator system shown together with a conventional resonator with a larger height taken along section line 5-5 in FIG. 3.
[0019] FIG. 6 is a perspective, cross-sectional view of resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0020] FIG. 7 is a perspective, cross-sectional view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0021] FIG. 8 is a cross-sectional side view of resonator chamber of the acoustic damping resonator system showing a reduced sized recirculation zone adjacent to and downstream of a resonator chamber, whereby a high heat transfer starting at a reattachment point is positioned closer to the resonator than in conventional systems taken along section line 5-5 in FIG. 3.
[0022] FIG. 9 is a cross-sectional side view of a conventional resonator chamber.
[0023] FIG. 10 is a cross-sectional side view of a resonator chamber of the acoustic damping resonator system taken along section line 5-5 in FIG. 3.
[0024] FIG. 11 is a cross-sectional side view of a conventional resonator chamber.
[0025] FIG. 12 is a cross-sectional side view of a resonator chamber of the acoustic damping resonator system taken along section line 5-5 in FIG. 3.
[0026] FIG. 13 is a cross-sectional side view of another embodiment of a resonator chamber of the acoustic damping resonator system taken along section line 5-5 in FIG. 3.
[0027] FIG. 14 is a cross-sectional side view of yet another embodiment of a resonator chamber of the acoustic damping resonator system taken along section line 5-5 in FIG. 3.
[0028] FIG. 15 is a cross-sectional top view of a conventional resonator chamber.
[0029] FIG. 16 is a cross-sectional top view of an embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0030] FIG. 17 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0031] FIG. 18 is a cross-sectional top view of an embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0032] FIG. 19 is a cross-sectional top view of a conventional resonator chamber.
[0033] FIG. 20 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0034] FIG. 21 is a cross-sectional top view of yet another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0035] FIG. 22 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0036] FIG. 23 is a cross-sectional top view of still another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0037] FIG. 24 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0038] FIG. 25 is a cross-sectional top view of a conventional resonator chamber.
[0039] FIG. 26 is a cross-sectional top view of another conventional resonator chamber.
[0040] FIG. 27 is a cross-sectional top view of an embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0041] FIG. 28 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0042] FIG. 29 is a cross-sectional top view of yet another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0043] FIG. 30 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0044] FIG. 31 is a cross-sectional top view of still another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0045] FIG. 32 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
[0046] FIG. 33 is a cross-sectional top view of another embodiment of the resonator chamber of the acoustic damping resonator system taken along section line 6-6 in FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
[0047] As shown in FIGS. 1-3, 5-8, 10, 12-14, 16-18, 20-24 and 27-33, an acoustically dampened gas turbine engine 10 having a gas turbine engine combustor 12 with an acoustic damping resonator system 14 is disclosed. The acoustic damping resonator system 14 may be formed from one or more resonators 16 formed from a resonator housing 18 positioned within the gas turbine engine combustor 12 at an outer housing 20 forming a combustor basket 22 and extending circumferentially within the combustor 12. In at least one embodiment, the resonator housing 18 may include one or more resonator chambers 24 that provide enhanced cooling with reduced risk of cracking and other damage. The resonator housing 18 may include resonator exhaust orifices 26 that may be positioned closer to an area of maximum temperature 28 within the combustor 12, thereby enabling the resonator 16 to reduce the temperature gradient within the combustor 12. The resonator housing 18 may be sized and configured to reduce stress found in conventional systems by increasing distances between resonator exhaust orifices 26 and between resonator inlet impingement orifices 30, among others.
[0048] In at least one embodiment, the acoustic damping resonator system 14 for a combustor 12 of a turbine engine 10 may include one or more resonator housings 18. The resonator housing 18 may extend for a portion of or entire around a combustor 12, as shown in FIGS. 2 and 3. In at least one embodiment, the resonator housing 18 may define one or more inner channels 32, as shown in FIGS. 2, 3 and 5, with an inner surface 34 and an outer surface 36 on an opposite side of the resonator housing 18 from the inner surface 34. In at least one embodiment, the resonator housing 18 may be generally cylindrical, thereby forming a ring with a single inner channel 32 therein.
[0049] The acoustic damping resonator system 14 may include one or more resonator chambers 24 extending radially outward from the resonator housing 18. The resonator chamber 24 may have any appropriate shape. In at least one embodiment, as shown in FIGS. 16-18, 22-24, 27, 32 and 33, the resonator chamber 24 may be shaped as a quadrilateral with a somewhat triangular shape, a rectangular shape, as shown in FIGS. 20-21 and 31, or other appropriate shape. As shown in FIGS. 12-14, the resonator chamber 24 may be formed from an outer wall 38 that may be supported by one or more sidewalls 40, such as upstream sidewall 42 and downstream sidewall 44. The resonator chamber 24 may include one or more resonator inlet impingement orifices 30 in the outer wall 38 of the resonator chamber 24 and one or more resonator exhaust orifices 26 extending through the resonator housing 18. The resonator exhaust orifice 26 extending through the resonator housing 18 may be offset axially upstream to place the resonator exhaust orifice 26 closer to an area of maximum temperature within the combustor 12.
[0050] In at least one embodiment, as shown in FIG. 12, the resonator 16 may be shifted further in the upstream direction relative to the resonator housing 18 such that the resonator 16 is closer to an area of maximum temperature within the combustor 12. In at least one embodiment, as shown in FIG. 14, the acoustic damping resonator system 14 may include a plurality of resonator exhaust orifices 26 that are positioned closer to an upstream wall 42 of the resonator chamber 24 than a downstream wall 44 of the resonator chamber 24. As shown in FIGS. 6, 7, 17, 18 and 21, the resonator exhaust orifices 26 may be spaced further apart from each other than in conventional systems, as shown in FIGS. 15 and 19 to reduce the likelihood of cracking in the resonator housing 18. The plurality of resonator exhaust orifices 26 may be separated from each other a distance equal to at least one and one half times a diameter of a smallest diameter of the plurality of resonator exhaust orifices 26. In another embodiment, the resonator exhaust orifices 26 may be separated from each other a distance equal to at least two times a diameter of a smallest diameter of the resonator exhaust orifices 26. In at least one embodiment, the resonator exhaust orifices 26 may be collected into a pattern having a shape of a quadrilateral with a somewhat triangular shape as shown in FIGS. 16-18 and 22-24, which may also be described as being an inverted triangle with a point of the triangle pointed downstream, a rectangular shape, as shown in FIGS. 20-21, or other appropriate shape.
[0051] As shown in FIGS. 22-24 and 33, the acoustic damping resonator system 14 may include one or more resonator inlet impingement orifices 30 that are offset from the plurality of resonator exhaust orifices 26 such that at least one of the plurality of resonator inlet impingement orifices 30 is radially aligned with the resonator housing 16 in which the plurality of resonator exhaust orifices 26 are positioned such that cooling fluids flowing into the resonator chamber 24 impinge on the resonator housing 16. As shown in FIGS. 23-24 and 33, the resonator inlet impingement orifices 30 may form fewer rows 46 as rows 48 formed by the plurality of resonator exhaust orifices 26. In another embodiment, as shown in FIGS. 23-24, the resonator inlet impingement orifices 30 may form half as many rows 46 as rows 48 formed by the plurality of resonator exhaust orifices 26. The rows 46 formed by the plurality of resonator inlet impingement orifices 30 may extend circumferentially and may be aligned radially between rows 48 of the plurality of resonator exhaust orifices 26 beginning with a first upstream row 50 of resonator exhaust orifices 26 and moving downstream. The rows 46 formed by the plurality of resonator inlet impingement orifices 30 may be positioned closer to an upstream sidewall 42 than a downstream sidewall 44 to increase efficiency. In at least one embodiment, the plurality of resonator inlet impingement orifices 30 may form a first row 52 that has one fewer orifices 30 than a first row 50 of resonator exhaust orifices 50. As shown in FIG. 24, the plurality of resonator inlet impingement orifices 30 may form a second row 54 downstream from the first row 52 of resonator inlet impingement orifices 30, whereby the second row 54 of resonator inlet impingement orifices 30 has at least two fewer orifices 30 than a second row 56 of resonator exhaust orifices 26. As shown in FIG. 24, the second row 54 of inlet impingement orifices 30 may skip a position in a middle of the second row 56 of resonator exhaust orifices 26.
[0052] In another embodiment, as shown in FIG. 33, the plurality of resonator inlet impingement orifices 30 may form a second row 54 downstream from the first row 52 of resonator inlet impingement orifices 30, whereby the second row 54 of resonator inlet impingement orifices 30 has at least one additional orifice 30 than a first row 52 of resonator inlet impingement orifices 30. The second row 56 of resonator exhaust orifices 26 may also include at least one additional resonator exhaust orifice 26 compared to a first row 50 of resonator exhaust orifices 26. A third row 58 of the resonator inlet impingement orifices 30 may have at least one less orifice 30 than a second row 54 of resonator inlet impingement orifices 30. A third row 59 of the resonator exhaust orifices 26 may have at least one less orifice 26 than a second row 56 of resonator exhaust orifices 26. The remaining rows of resonator inlet impingement orifices 30 and resonator exhaust orifices 26 may reduce in number moving downstream towards the downstream sidewall 44.
[0053] In at least one embodiment, the plurality of inlet impingement orifices 30 may be separated from each other a distance equal to at least one and one half times a diameter of a smallest diameter of the plurality of inlet impingement orifices 30. In another embodiment, the plurality of inlet impingement orifices 30 may be separated from each other a distance equal to at least two times a diameter of a smallest diameter of the plurality of inlet impingement orifices 30.
[0054] In at least one embodiment, as shown in FIGS. 5, 8, 27-32, the resonator chamber 24 may be configured to increase cooling of the resonator housing 18 and the combustor 12 without increasing the amount of cooling air needed. In particular, the resonator chamber 24 may be reconfigured to extend for a larger distance axially with a smaller radial height, thereby keeping the volume within the resonator chamber 24 relatively unchanged in comparison to conventional systems but exposing a larger amount of surface area of the resonator housing 18 to cooling fluids. In addition, the resonator chamber 24 may extend further radially upstream than conventional systems, which enables the upstream sidewall 42 of the resonator chamber 24, resonator exhaust orifices 26 or resonator inlet impingement orifices 30, or any combination thereof, to be shifted upstream and closer to an area of maximum temperature 28 within the combustor 12. In at least one embodiment, a ratio of distance between the outer wall 38 of the resonator chamber 24 and the resonator housing 18 to a diameter of the resonator inlet impingement orifice 30 may be between about seven and about four. In another embodiment, the ratio of distance between the outer wall 38 of the resonator chamber 24 and the resonator housing 18 to the diameter of the resonator inlet impingement orifice 30 is about 6.5 in the middle of the resonator 16. By decreasing the height of the resonator chamber 24, resonator 16 experiences improved cold side cooling downstream, in relation to the cold side flow direction, of the resonators 16 because of formation of a smaller recirculation zone adjacent to the sidewall 40 than in conventional systems. As such, a smaller low heat transfer region develops adjacent the recirculation zone. Instead, the high heat transfer at the reattachment point develops closer to the resonator 16 than in conventional systems.
[0055] The outer wall 38 of the resonator chamber 24 may be configured to enhance the flow of cooling fluids through the resonator inlet impingement orifices 30 and enhance the impingement of cooling fluids on the resonator housing 18 within the resonator chamber 24. In at least one embodiment, as shown in FIG. 10, the outer wall 38 of the resonator chamber 24 may be thicker than conventional systems, as shown in FIG. 9, to increase the effectiveness of the resonator inlet impingement orifices 30. In at least one embodiment, the outer wall 38 may be sized in thickness such that a ratio of a length of the at least one resonator inlet impingement orifice 30 extending radially inward to a diameter of the resonator inlet impingement orifice 30 is greater than about 0.75. In another embodiment, the outer wall 38 may be sized in thickness such that a ratio of a length of the at least one resonator inlet impingement orifice 30 extending radially inward to a diameter of the resonator inlet impingement orifice 30 is greater than about one.
[0056] In at least one embodiment, as shown in FIGS. 5, 8, 27-32, the acoustic damping resonator system 14 may be configured such that the footprint of the resonator chamber 24 may be enlarged relative to conventional resonators, yet prevent a maximum internal resonator dimension 60 extending linearly within the resonator chamber 24 from being enlarged beyond a point at which the resonator chamber 24 has a target cutoff frequency that is greater than an actual damping frequency. The shape of the resonator 16 may be adapted such that the maximum internal resonator dimension 60 is not increased in the same relation as the resonator footprint. With the adapted resonator shape, a shift of the cut off frequency to higher frequencies is enabled, which ensures reliable damping in the designed frequency range of the resonator 16. As such, the acoustic damping resonator system 14 may be formed from a resonator housing 18 with a one or more resonator chambers 24 as described above. A ratio of a distance between the outer wall 38 of the resonator chamber 24 and the resonator housing 18 to a diameter of the resonator inlet impingement orifice 30 may be between about seven and about four. As shown in FIGS. 29-31, a maximum internal resonator dimension 60 extending linearly within the resonator chamber 24 may be increased less than 12 percent while a footprint of the resonator chamber 24 on the resonator housing 18 may have been enlarged by between 40 percent and 100 percent relative to a resonator chamber 24 having a ratio of greater than eight of a distance between the outer wall 38 of a resonator chamber 24 and a resonator housing 18 to a diameter of a resonator inlet impingement orifice 30. The resonator chamber 24 may have been enlarged and sized, as set forth above.
[0057] The acoustic damping resonator system 14 may include resonator chambers 24 having numerous different shapes configured to prevent a maximum internal resonator dimension 60 extending linearly within the resonator chamber 24 from being enlarged beyond a point at which the resonator chamber 24 has a target cutoff frequency that is greater than an actual damping frequency. In at least one embodiment, a cross-sectional shape of outer sidewalls 40 forming the resonator chamber 24 may form a modified parallelogram 66, as shown in FIG. 30, in which a maximum internal resonator dimension 60 has been reduced via truncated intersections 64. The truncated intersections 64 of the modified parallelogram 66 may be formed with a first corner side 68 at a first intersection 70 and a second corner side 72 at a second intersection 74. The first corner side 68 may extend between first and second sidewalls 76, 78 forming the modified parallelogram 66. The second corner side 72 may extend between third and fourth sidewalls 80, 82 forming the modified parallelogram 66.
[0058] In another embodiment, as shown in FIG. 29, a cross-sectional shape of outer sidewalls 40 forming the resonator chamber 24 may form a modified triangle 84 in which at least two corners 86 have been truncated with corner sides 88. In at least one embodiment, each corner of the modified triangle 84 may be truncated with at least one corner side 88 such that a first corner side 68 may extend between first and second sidewalls 76, 78, a second corner side 72 may extend between second and third sidewalls 78, 80 and a third corner side 90 may extend between first and third sidewalls 76, 80.
[0059] In yet another embodiment, as shown in FIG. 31, a cross-sectional shape of outer sidewalls 40 forming the resonator chamber 24 may form a modified rectangle 92 in which at least two corners 86 have been truncated with corner sides 88. At least two corners 86 of the modified rectangle 92 may have been truncated with one or more corner sides 88. In at least one embodiment, each corner 86 of the modified rectangle 92 may have been truncated with at least one corner side 88 such that a first corner side 68 may extend between first and second sidewalls 76, 78, a second corner side 72 may extend between second and third sidewalls 78, 80, a third corner side 90 may extend between third and fourth sidewalls 80, 82 and a fourth corner side 94 may extend between first and fourth sidewalls 76, 82. In at least one embodiment, the modified rectangle 92 may have equal length sides and be a square.
[0060] As shown in FIG. 32, one or more corners 86 on one or more sidewalls 40 forming the resonator chamber 24 may be curved. In at least one embodiment, each corner 86 on each sidewall 40 forming the resonator chamber 24 may be curved.
[0061] The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention or the following claims.
