DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 07/23/2026 has been entered.
Claims 1-6 and 10-14 are currently being examined.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-6, 10-11, and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over NPL Rauch NASA CR-120,992 in view of Rudrapatna et al. 20080148738 and Stratton 20230194096.
Regarding independent claim 1, Rauch teaches a gas turbine engine (Fig. 10), comprising:
a compressor section (labeled in annotated Fig. 10), a combustion section (labeled in annotated Fig. 10), and a turbine section (labeled in annotated Fig. 10), wherein the gas turbine engine defines a rotational axis (labeled in annotated Fig. 10) and the combustion section includes:
a flow turning combustor (flow turning combustor shown in combustor section of Fig. 10) comprising:
a combustor liner (labeled in annotated Fig. 10) that at least partially defines a combustion chamber (labeled in annotated Fig. 10) including:
a combustor inlet (labeled in annotated Fig. 10) having an inlet height (a chosen portion of combustor inlet with a height of 1 inch based on scale; as claim does not provide end points or boundary for combustor inlet or for inlet height, any portion of combustor inlet and corresponding height may be chosen which meets the claimed limitation),
a combustor outlet (labeled in annotated Fig. 10) having an outlet height (in Fig. 10 outlet height is about 1.5 inches based on scale; as claim does not provide end points or boundary for combustor outlet or for outlet height, any portion of combustor outlet and corresponding height may be chosen which meets the claimed limitation) and fluidly coupled with the turbine section (combustor outlet is fluidly coupled with turbine section in annotated Fig. 10),
a primary section (labeled in annotated Fig. 10) having a primary length (labeled in annotated Fig. 10 which is 9 inches based on scale) defined between an aft end (labeled in annotated Fig. 10) of the primary section adjacent to the combustor inlet (aft end is adjacent to combustor inlet) and a forward end (labeled in annotated Fig. 10) of the primary section, the primary section being a straight section (primary section is a straight section as seen in annotated Fig. 10) extending from the aft end to the forward end in an axially forward direction relative to the rotational axis (primary section extends from aft end to forward end in axially forward direction relative to rotational axis in annotated Fig. 10), the forward end of the primary section being positioned forward of the combustor outlet (forward end is positioned forward of combustor outlet in annotated Fig. 10), and
a transition section extending from the forward end of the primary section and forward of the combustor outlet (transition section extends from forward end and transition section is forward of combustor outlet) to the combustor outlet (in annotated Fig. 10, transition section extends from forward end of primary section to combustor outlet), the transition section defining a turn (labeled in annotated Fig. 10) that extends in an axially aft direction toward the combustor outlet relative to the rotational axis (turn extends in axially aft direction toward combustor outlet relative to rotational axis in annotated Fig. 10);
wherein the flow turning combustor defines a combustor centerline (labeled in annotated Fig. 10) extending from the combustor inlet to the combustor outlet (combustor centerline extends from combustor inlet to combustor outlet in annotated Fig. 10), and includes a combustor length (about 15 inches based on scale in annotated Fig. 10 which shows primary length from combustor inlet to where turn starts is about 9 inches and the length of combustor centerline from where turn starts to combustor outlet is about 6 inches based on the scale which adds up to 15 inches) measured along the combustor centerline from the combustor inlet to the combustor outlet (combustor length is measured along combustor centerline from combustor inlet to combustor outlet in annotated Fig. 10), and
wherein a ratio of a first product of the combustor length and the outlet height (15x1.5= 22.5) to a second product of the inlet height and the primary length (1x9=9) is at least 2 (ratio of 22.5/9 is 2.5 which is at least 2 as claimed).
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Rauch is does not explicitly teach a hydrogen fuel supply; and
a fuel nozzle assembly fluidly coupled with the hydrogen fuel supply and the combustor inlet.
Rudrapatna teaches in Fig. 1 a similar gas turbine engine and combustor as Rauch and teaches per [0011] fuel is supplied to the combustor 8 through fuel tubes 9 which is mixed with air from the plenum 7 when sprayed through nozzles, i.e., fuel nozzles, into the combustor 8 as a fuel air mixture that is ignited, such that fuel tubes 9 are fluidly coupled with fuel nozzles which are fluidly coupled with combustor inlet at aft end of combustor 8 as shown in Fig. 1 to spray fuel into combustor 8 and fuel tubes 9 are a fuel supply in light of instant specification [0039] which describes a fuel supply as a fuel manifold or conduit that supplies fuel.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the invention of Rauch to have a fuel supply and a fuel nozzle assembly fluidly coupled with the fuel supply and the combustor inlet as taught by Rudrapatna to supply fuel to the fuel nozzle assembly which in turn provides fuel to the combustor for combustion with air as combining prior art elements according to known methods to yield predictable results.
"The combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results. . . . [W]hen a patent 'simply arranges old elements with each performing the same function it had been known to perform' and yields no more than one would expect from such an arrangement, the combination is obvious." KSR at 1395-66 (citing Sakraida v. AG Pro, Inc., 425 U.S. 273, 282 (1976)).
Rauch in view of Rudrapatna is silent regarding the fuel supply is a hydrogen fuel supply.
Stratton teaches a gas turbine engine (Fig. 1) and combustor (Fig. 4) similar to that of Rauch and Rudrapatna, and teaches hydrogen is a fuel which may be used in the gas turbine engine for an aircraft [0002].
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Rauch in view of Rudrapatna to have the fuel supply be a hydrogen fuel supply as taught by Stratton as hydrogen is a suitable fuel for the gas turbine engine. The selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945).
Regarding claim 2, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and teaches as discussed above the outlet height is greater than the inlet height (as discussed above in claim 1, outlet height is 1.5 inches and inlet height is 1 inch, such that outlet height is greater than inlet height as claimed).
Regarding claim 3, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches the combustor inlet is aft of the combustor outlet (as shown in annotated Fig. 10 combustor inlet is aft of combustor outlet).
Regarding claim 4, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches the turn is at least 60 degrees and less than 240 degrees (in annotated Fig. 10, the turn is about 180 degrees as direction of flow of combustion gases through combustion chamber first flows in forward direction from beginning of transition section to flowing radially inward through the turn to finally flowing in aft direction at combustor outlet, such that about 180 degrees is within claimed range of at least 60 degrees and less than 240 degrees).
Regarding claim 5, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches the combustor centerline at the combustor outlet is angled at a first angle relative to a centerline of the combustion section (labeled in annotated Fig. 10); and wherein the first angle is at least -30 degrees and less than 30 degrees (combustor centerline at combustor outlet in annotated Fig. 10 is substantially parallel to centerline of combustion section such that the combustor centerline at the combustor outlet is angled at a first angle of about zero degrees relative to centerline of combustion section which is within the claimed range of at least -30 degrees and less than 30 degrees).
Regarding claim 6, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches the centerline at the combustor inlet is angled at a second angle relative to the centerline of the combustion section; and wherein the second angle is at least -30 degrees and less than or equal to 90 degrees (combustor centerline at combustor inlet in annotated Fig. 10 is substantially parallel to centerline of the combustion section such that the combustor centerline at the combustor inlet is angled at a second angle of about zero degrees relative to centerline of the combustion section which is within the claimed range of at least -30 degrees and less than 90 degrees).
Regarding claim 10, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches the combustor centerline includes a U- shaped configuration (as seen in annotated Fig. 10, combustor centerline includes a U-shaped configuration).
Regarding claim 11, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches the transition section includes a first portion defining the turn (in annotated Fig. 10 transition section includes a first portion defining the turn) and a second portion that is straight (a second portion which is just aft of first portion in annotated Fig. 10 is straight).
Regarding claim 13, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above and teaches the fuel nozzle assembly is positioned to emit hydrogen fuel (fuel nozzle assembly of Rauch as modified in view of Rudrapatna is positioned to emit fuel into combustor inlet and as modified in view of Stratton the fuel nozzle assembly emits hydrogen fuel as discussed above in claim 1) and Rudrapatna further teaches the fuel nozzle assembly is positioned to emit fuel forward into the combustor inlet (fuel tubes 9 are connected to fuel nozzle assembly at aft end of combustor 8 in Fig. 1 which is at combustor inlet such that fuel nozzle is positioned to emit fuel forward into combustor inlet).
Claim(s) 12 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over NPL Rauch NASA CR-120,992 in view of Rudrapatna et al. 20080148738 and Stratton 20230194096 as applied to claim 1 above, and further in view of Giambra et al. 20190032920.
Regarding claim 12, Rauch in view of Rudrapatna and Stratton teaches all that is claimed above, and Rauch further teaches an axial offset (labeled in annotated Fig. 10 below) between the combustor inlet and the combustor outlet is greater than 0% and is equal to about 8 inches per scale in Fig. 10 which is about 533% of the outlet height which is 1.5 inches in annotated Fig. 10, wherein the axial offset is measured in an axial direction parallel to the rotational axis (in annotated Fig. 10 axial offset is measured in axial direction parallel to rotational axis of gas turbine engine) between an aftmost portion of the combustor inlet (labeled in annotated Fig. 10) and an aftmost portion of the combustor outlet (labeled in annotated Fig. 10), but Rauch is silent regarding the axial offset is less than or equal to 400% of the outlet height.
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Giambra teaches a flow turning combustor (130 Fig. 3) similar to Rauch. Annular liner assembly 200 includes a straight portion 260, a dilution portion 232 and a turn portion 234, with straight portion 260 extending from a first end (A) at the dome assembly 202 defined by a flare cone 207 of fuel nozzle assembly 204; straight portion 260 is a primary zone or igniting zone; and dome assembly 202 defines a dome inlet 205 having a predetermined height or dome height (H), defining a diameter at the first end (A), with straight portion 260 terminating just forward of the plane of the dilution holes 214 in the dilution portion 232 at a second end (B) to define an axial length (S) between 90% and 130% of the dome height (H) from the flare cone 207 and dilution portion 232 defines an axial length (T) equal to or less than 30% of the dome height (H); and a tangency curve 262 from where the turn portion 234 begins can be located at an axial distance (S+T) between 110% and 150% of the dome height (H) and turn portion 234 extends from the third end (C) to a fourth end (D) defining a combustor outlet 264 (per [0034-0037]). Flow turning combustor 130 of Fig. 3 has the final stage of dilution mixing occur in the turn portion so that 130 is shorter in length than prior art flow turning combustor 30 of Fig. 2 in which axial length (AL) measured from the flare cone 107 to the tangency curve 162 is at least 180% of the dome height (DH) (per [0030]).
The shorter combustor minimizes an overall length combusted gases flow within a combustor chamber and reduces cooled surface area requirements to minimize cooling air required to maintain liner temperatures within acceptable limits, while still permitting a sufficient primary zone volume for flame stabilization and ignition, and there is also a benefit in terms of engine weight and packaging by providing an overall shorter combustion liner and casing and the saving of cooling air requirements permits application of a reverse flow combustor, i.e., flow turning combustor, to a higher pressure ratio cycle (per [0042-0043]).
Therefore, axial length of the combustion zone and dilution portion of the flow turning combustor are result-effective variables. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to optimize the axial length of the combustion zone and dilution portion of the flow turning combustor of Rauch to be shorter as taught by Giambra to minimize an overall length combusted gases flow within the combustor chamber and reduce cooled surface area requirements to minimize cooling air required to maintain liner temperatures within acceptable limits, while still permitting a sufficient primary zone volume for flame stabilization and ignition, and there is also a benefit in terms of engine weight and packaging by providing an overall shorter combustion liner and casing and the saving of cooling air requirements permits application of a reverse flow combustor, i.e., flow turning combustor, to a higher pressure ratio cycle. Optimizing the combustor length to be shorter also results in the axial offset being shorter such that axial offset may be less than or equal to 400% of the outlet height as claimed.
Regarding claim 14, Rauch in view of Rudrapatna and Stratton and further in view of Giambra teaches all that is claimed above, and Rauch further teaches a radial offset (labeled in annotated Fig. 10 above) between the combustor inlet and the combustor outlet is at least 30% and less than or equal to 250% of the outlet height (radial offset in annotated Fig. 10 is about 1.5 inches per scale which is equal to outlet height of 1.5 inches such that radial offset is 100% of outlet height, which is within range of at least 30% and less than or equal to 250% of the outlet height as claimed), wherein the radial offset is measured in a radial direction (direction perpendicular to rotational axis of gas turbine engine in annotated Fig. 10 above) between a most radially inward portion (labeled in annotated Fig. 10) of the combustor inlet and a most radially outward portion (labeled in annotated Fig. 10) of the combustor outlet.
Response to Arguments
Applicant's arguments filed 06/23/2026 have been fully considered but they are not persuasive.
Applicant argues in Remarks page 8 under 103 rejections, that the annotated Fig. 10 of prior art Rauch used in the Final Rejection does not identify the newly claimed straight primary section and does not identify the newly claimed limitation of a forward end positioned forward of the combustor outlet and a transition section extending from that forward end and turning in an axially aft direction toward the combustor outlet.
However, in the current 103 rejection of claim 1 above, Figure 10 has been annotated to show that Rauch does show the newly claimed limitations of a straight primary section and a forward end positioned forward of the combustor outlet and a transition section extending from that forward end and turning in an axially aft direction toward the combustor outlet, with a combustor outlet currently being interpreted as further aft in annotated Figure 10, which is a scaled drawing as shown by the scale in the lower right portion of the figure.
Amended claim 1 claims a combustor outlet being fluidly coupled with the turbine section but claim 1 does not provide end points or a particular boundary for a combustor outlet, such that Rauch discloses the claimed combustor outlet which is aft of a forward end of the primary section as shown in annotated Figure 10 of Rauch above.
Applicant does not argue the dependent claims.
Conclusion
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/A.J.H./ Examiner, Art Unit 3741
/GERALD L SUNG/Primary Examiner, Art Unit 3741
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