Patent Application
20240263796
A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-pressure and temperature exhaust gas flow. The high-pressure and temperature exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section may include low and high pressure compressors, and the turbine section may also include low and high pressure turbines.
Present gas turbine engines use liquid hydrocarbon fuels (LHF). LHF is provided through a fuel supply system and introduced into the combustor by liquid injectors. The fuel supply system and liquid injectors are designed for handling and efficient burning of the LHF. For instance, as liquid is much denser than the air (gas) it is to be mixed with, it is necessary for the liquid injectors to atomize the LHF into tiny droplets in order to facilitate more uniform burning. More recently it has been proposed to utilize hydrogen (H2) as a fuel.
A gas turbine engine according to an example of the present disclosure includes a combustion chamber and groups of injectors for introducing a hydrogen and gas mixture into the combustion chamber. Each group of injectors includes radially inner, outer, and intermediate injectors, and each injector includes a hydrogen feed conduit that has an open-cell metallic foam disposed therein.
The present disclosure may include any one or more of the individual features disclosed above and/or below alone or in any combination thereof.
The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding elements.
While present gas turbine engines use liquid hydrocarbon fuels (LHF), the engine 20 of the present disclosure is designed to use gaseous fuel, such as hydrogen, in the fuel system 32. In this regard, the fuel system 32 may carry liquid cryogenic hydrogen or gaseous hydrogen, both of which are provided to the combustor section 26 as gaseous hydrogen. A challenge to using hydrogen is that because it is a gas, its handling and combustion properties differ from that of LHF. For instance, hydrogen does not require atomization like a liquid, and hydrogen has higher flammability and different flame characteristics than LHF. Accordingly, injector nozzles and combustors that are designed for hydrogen are needed. In these regards, the engine 20 includes a combustion system 38 that is configured for introducing the hydrogen fuel into the combustor section 26.
There are groups 42 (one representative group shown) of injectors at the first axial end 40a that are connected to the fuel system 32 (hydrogen source) and the compressor section 24 for introducing a hydrogen and air mixture into the combustion chamber 40. The groups 42 are circumferentially arranged about the engine axis A. Each group 42 has three radially-arranged injectors, which include radially inner, intermediate, and outer injectors 44/46/48.
Each injector 44/46/48 includes an injector body 50 that defines one or more hydrogen feed conduits 52 and one or more air feed conduits 54. In general, the size (at the conduit exits) of all of the hydrogen feed conduits 52 are equivalent, and the size (at the conduit exit) of all of the air feed conduits 54 are equivalent, although the sizes may differ between the hydrogen feed conduits 52 and the air feed conduits 54. Each of the hydrogen feed conduits 52 includes an open-cell metallic foam 56 disposed therein. The foam 56 serves as a flame arrestor, allowing feed flow of hydrogen but facilitating the prevention of flame propagation back through the injector 44/46/48 For instance, the open-cell metallic foam 56 is formed of an alloy that has low susceptibility to hydrogen embrittlement, such as but not limited to, stainless steel or nickel alloy, and which is corrosion resistant and temperature resistant at the expected operating conditions. A “conduit” as used herein is defined by one or more structures that together convey a fluid from one point to another. For example, a conduit conveying fluid from point A to point B may include one of, or a combination of: a tube, an aperture defined through a part of an engine, a filter, a pump, and so on, depending on the application and context as would be understood by a person of ordinary skill in the art reading the present disclosure.
Each of the injectors 44/46/48 is an annular injector 58, a representative example arc section of which is shown in axial view in
In the example of
The axial location and the radial orientation of each main injector 44/48 and its injector body 50 can be optimized for flame stability, combustion efficiency, liner durability and minimal NOx emission.
The outer main injector 48 may be arranged to have a higher fuel-air ratio than the inner main injector 44, hence exhausting with a higher gas temperature at the tip than the root of the turbine blades downstream. Such setting of the fuel-air mixture ratio across the outer, intermediate and inner fuel injectors can be optimized for turbine efficiency and hot section durability.
The combustion chamber 40 may also include cooling jets 64 for introducing additional air for combustion and cooling the walls of the chamber 40. Some of the cooling jets 64 are located in conical fairings 66 located radially between, respectively, the inner and intermediate injectors 44/46 and the outer and intermediate injectors 48/46. The fairings 66 bound a radial portion of the mixing region 60 and facilitate downstream flow of the hydrogen and air mixture into the combustion chamber 40. For example, the groups 42 of injectors introduce 70% to 80% of the air through the passages 54 for combustion into the combustion chamber 40, and the cooling jets 64 introduce 10% to 20% of the air for combustion into the combustion chamber 40. Such percentages enable a lean burn of the hydrogen, which also facilitates low NOx emissions.
This disclosure may be further understood in view of the following examples. A turbine engine 20 according to an example of the present disclosure includes a combustion chamber 40 disposed about an axis A and having first and second axial ends 40a/40b and radially inner and outer walls 40c/40d. Groups 42 of injectors 44/46/48 are disposed about the axis A at the first axial end 40a for introducing a hydrogen and gas mixture into the combustion chamber 40. Each of the groups 42 includes radially inner, outer, and intermediate injectors 44/46/48. Each of the injectors 44/46/48 has a hydrogen feed conduit 52 including an open-cell metallic foam 56 disposed therein.
In a further example of the foregoing example, the intermediate injector 46 is a pilot injector for introducing a first percentage of the hydrogen and gas mixture into the combustion chamber 40.
In a further example of any of the foregoing examples, the radially inner and outer injectors 44/48 are main injectors for introducing a second percentage of the hydrogen and gas mixture into the combustion chamber 40.
In a further example of any of the foregoing examples, the combustion chamber 40 includes first and second conical fairings 66 radially between, respectively, the inner and intermediate injectors 44/46 and the outer and intermediate injectors 48/46.
In a further example of any of the foregoing examples, the first and second conical fairings 66 include cooling jets 64.
In a further example of any of the foregoing examples, the groups include pilot groups 142a in which the injectors are pilot injectors 144a/146a/148a for introducing a first percentage of the hydrogen and gas mixture into the combustion chamber 40.
In a further example of any of the foregoing examples, the groups include main groups 142b in which the injectors are main injectors 144b/146b/148b for introducing a second percentage of the hydrogen and gas mixture into the combustion chamber 40.
In a further example of any of the foregoing examples, the pilot groups and the main groups 142a/142b circumferentially alternate such that each of the pilot groups 142a is circumferentially between two of the main groups 142b and each of the main groups 142b is circumferentially between two of the pilot groups 142a.
In a further example of any of the foregoing examples, the pilot groups 142a each have first arc length L1 about the axis A, the main groups 142b each have a second arc length L2 about the axis A, and the first arc length L1 is smaller than the second arc length L2.
Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.
| Number | Date | Country | |
|---|---|---|---|
| 63482854 | Feb 2023 | US |
