Hydrogen combustion device
The hydrogen combustion device with a premixing chamber and dual injection systems addresses stability and emission issues by optimizing mixing and combustion, achieving stable and low NOx operation.
Patent Information
- Authority / Receiving Office
- US · United States
- Patent Type
- Applications(United States)
- Current Assignee / Owner
- OFFICE NAT DETUDES & DE RECH AEROSPATIALES
- Filing Date
- 2023-12-18
- Publication Date
- 2026-07-23
AI Technical Summary
Existing hydrogen combustion devices in turbomachines face challenges with stable combustion, high flame temperatures, nitrogen oxide emissions, and flashback risks due to hydrogen's unique combustion characteristics, necessitating a solution that ensures stable and low NOx emissions while managing thermal loads.
A hydrogen combustion device with a premixing chamber and dual injection systems: one for mixing hydrogen and air homogeneously and another for stabilizing combustion, utilizing micro-injectors and angled orifices to optimize mixing and combustion stability.
The device achieves aerodynamically stable combustion with reduced nitrogen oxide emissions and minimized thermal stress, ensuring efficient and reliable operation.
Smart Images
Figure US20260210550A1-D00000_ABST
Abstract
Description
FIELD OF THE INVENTION
[0001] The present disclosure relates to the field of combustion such as in particular of hydrogen for a turbine, in particular for a turbomachine, such as for example an aircraft gas turbine, turbojet or turboprop. More specifically, the present disclosure relates to a hydrogen combustion device.DESCRIPTION OF RELATED ART
[0002] An aircraft turbomachine conventionally comprises a combustion chamber supplied with kerosene. However, in order to reduce the environmental impact and the polluting emissions and to contribute to reducing carbon dioxide emissions from air transport, replacing the kerosene by a hydrogen-based combustion was conceived.
[0003] In order to allow stable hydrogen combustion, generating diffusion flames in the combustion chamber is known, meaning flames which are obtained with reactants very slightly mixed with air, or even unmixed, before arriving in the combustion chamber.
[0004] However, these diffusion flames arising from hydrogen combustion reach higher temperatures than the flames from kerosene combustion under equivalent thermodynamic and enrichment conditions. “Enrichment” is understood to mean the proportion of hydrogen relative to the air for combustion. The mixture is called “rich” when the hydrogen is in excess relative to the air, and inversely, the mixture is called “poor” when the air is in excess relative to the hydrogen. The combustion chamber must then be able to resist these high temperatures.
[0005] Further, the speeds of flames coming from hydrogen combustion are higher than those coming from kerosene combustion. These significant flame speeds may generate flame returns, commonly called “flashbacks,” in systems for injection of combustibles into the combustion chamber. These flashbacks may consequently damage the injection systems.
[0006] Further, the temperatures produced by hydrogen consumption are highly emitting of nitrogen oxides (NOx).
[0007] Consequently, there is a need for developing hydrogen combustion devices which allow stable combustion and low emission of nitrogen oxides, while limiting the thermal load experienced by the combustion devices and the risks of flashback.
[0008] The present document aims to provide a solution to this need which is simple, reliable and economical.BRIEF SUMMARY OF THE INVENTION
[0009] A hydrogen combustion device is proposed, comprising:
[0010] a combustion chamber and at least one premixing chamber having a first axis and an outlet which opens into the combustion chamber;
[0011] at least one first system for injecting a mixture of hydrogen and air into the combustion chamber along the first axis, where the first injection system comprises the premixing chamber, primary means of bringing air opening into the premixing chamber and at least one first hydrogen inlet orifice opening into the premixing chamber downstream in the flow direction of the gases in the combustion device from the primary means of bringing air;
[0012] optionally, at least one second system for injecting hydrogen into the combustion chamber along a second axis, where the second injection system comprises at least one second hydrogen inlet orifice opening into the combustion chamber.
[0013] In a specific implementation, said at least one first hydrogen inlet opens into the premixing chamber along a direction forming an angle included between 30° and 150° with the first axis. This orientation of the hydrogen flow coming from the primary means of bringing air into the premixing chamber serves to improve the homogeneity and speed of mixing hydrogen and air. In a specific implementation, the angle may be 90°.
[0014] On the one hand, said at least first injection system advantageously serves to provide a rapid and sufficiently homogeneous mixing of the air and hydrogen in the premixing chamber before supplying the combustion chamber with this mixture. On the other hand, said optional second injection system advantageously serves to stabilize the combustion process in the combustion chamber, in particular at low regime. Such a combustion device thus allows development of a combustion that is both aerodynamically stable and weakly emitting of nitrogen oxides in the combustion chamber. Further, the combustion device according to the present disclosure maintains the advantage of being easily optimized, designed and produced.
[0015] The characteristics disclosed in the following paragraphs may, optionally, be implemented independently of each other or in combination with each other.
[0016] Said at least one first orifice corresponds in particular to a premixing orifice opening directly into the premixing chamber. Further, said optional second orifice corresponds in particular to a direct injection orifice, opening directly into the combustion chamber.
[0017] Said at least one first orifice may comprise at least one annular row of first orifices, for example an annular row of first orifices or alternatively a plurality of annular rows of first orifices spaced longitudinally. The annular row of first orifices advantageously serves to annularly distribute the hydrogen supply from the premixing chamber, and thus to improve the homogeneity of the hydrogen and air mixture in the premixing chamber.
[0018] Each annular row of first orifices may comprise two first orifices, for example arranged diametrically opposite relative to the premixing chamber.
[0019] Said first orifices of the annular row may be aligned circumferentially such that at least some of the first orifices, preferably all of the first orifices, are intercepted by a single plane perpendicular to the first axis.
[0020] Said at least first injection system may advantageously comprise an annular hydrogen supply ramp surrounding the premixing chamber of said first injection system. Said annular ramp may in particular comprise at least one annular row of first orifices, preferably one annular row of first orifices. The annular ramp is then configured for supplying the premixing chamber with hydrogen through the first orifices of the annular row. With this configuration, the implementation of the annular row of first orifices may be easier.
[0021] Each of said at least one first injection system may comprise at least one micro-injector configured for propelling a hydrogen micro-jet into the premixing chamber by injection through said at least one first orifice.
[0022] Said at least one first orifice must open into the premixing chamber along the first axis, downstream from the primary means of bringing air and ideally near it. This configuration serves to improve the efficiency of mixing hydrogen and air.
[0023] Advantageously the premixing chamber may be delimited on the outside by a cylindrical wall in which said at least one first orifice is formed.
[0024] Each of said at least one first orifice may have a diameter included between 0.2 mm and 3 mm.
[0025] Each of said at least one second injection system may comprise at least one micro-injector configured for propelling hydrogen micro-jets through said at least one second orifice and into the combustion chamber.
[0026] Each of said at least one second orifice may have a diameter included between 0.2 mm and 3 mm.
[0027] Advantageously, the primary means of bringing air may be configured for supplying the premixing chamber with swirling air. This characteristic serves to improve the control of the aerodynamics in the premixing chamber, by promoting a rapid and substantially homogeneous mixing of the air and the hydrogen in the premixing chamber.
[0028] Advantageously, the first injection system may comprise secondary means of bringing air opening into the premixing chamber downstream from said at least one first orifice, preferably at a downstream end of the premixing chamber. Advantageously these means of bringing air serve to limit the risk of backdraft in the premixing chamber.
[0029] The secondary means of bringing air may comprise at least one third orifice opening into the premixing chamber downstream from said at least one first orifice, preferably at a downstream end of the premixing chamber.
[0030] Said at least one third orifice may be oriented radially inward and towards the downstream along the first axis.
[0031] The first injection system may advantageously comprise at least one annular row of third orifices, for example one annular row of third orifices. Each annular row of third orifices may for example comprise two third orifices, preferably arranged diametrically opposite relative to the premixing chamber. The two third orifices may for example be arranged respectively radially inward and radially outward from the premixing chamber relative to a longitudinal axis of the combustion Each of said at least one third orifice may have a diameter included between 0.05 mm and 3 mm.
[0032] Further, the combustion chamber may be annular or tubular.
[0033] The combustion chamber may comprise a chamber bottom annular wall with axis coincident with the longitudinal axis or a set of tubular chambers, whose direction are not necessarily parallel, distributed around the longitudinal axis.
[0034] Said at least one first injection system may open into the combustion chamber at the same longitudinal position as said at least one second injection system along the longitudinal axis.
[0035] Said at least one second injection system may be arranged radially inward or radially outward from said at least one first injection system along the first axis.
[0036] The second axis may be inclined radially inward compared to the first axis.
[0037] Advantageously, for an annular geometry combustion chamber, the outlet of the premixing chamber opens at the inlet of the combustion chamber and through the chamber bottom annular wall of the combustion chamber.
[0038] The combustion device may comprise a plurality of first injection systems distributed annularly around the longitudinal axis of the combustion chamber.
[0039] The combustion device may comprise a plurality of second injection systems distributed annularly around the longitudinal axis of the combustion chamber.
[0040] The combustion device may comprise means for regulating the supply of hydrogen and air to the premixing chamber configured for implementing a poor hydrogen and air mixture in the premixing chamber. The premixing chamber is advantageously intended to receive this poor hydrogen and air mixture. “Poor” is understood to mean the air is in excess relative to the hydrogen in the premixing chamber. “Rich” is understood to mean that hydrogen is in excess relative to the air in the pre-mixing chamber. Combustion of the poor premixture advantageously serves to reduce the flame temperature in the combustion chamber, and thus to reduce the nitrogen oxides emitted.
[0041] The means for regulation of the hydrogen and air supply to the premixing chamber may in particular be configured for distributing a flow of air arriving into the premixing chamber between the primary means of bringing air and the secondary means of bringing air. The primary means of bringing air may in particular be configured for supplying the premixing chambers with air with a mass flow rate between two and five times greater than the mass flow rate of air brought by the secondary means.
[0042] According to another aspect, a turbomachine is proposed comprising the combustion device as previously described.BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Other characteristics, details and advantages will appear upon reading the following detailed description, and analyzing the attached drawings, on which:
[0044] FIG. 1 schematically shows a partial section view of a combustion device according to the present disclosure.
[0045] FIG. 2 schematically shows another partial section view of a combustion device according to the present disclosure.DETAILED DESCRIPTION OF THE INVENTION
[0046] Now referring to FIGS. 1 and 2 which respectively represent schematically partial section views of examples of the hydrogen combustion device 100 according to the present document. The combustion device 100 may be implemented in a gas turbine, or a turbomachine, for example an aircraft turboprop or turbojet.
[0047] The combustion chamber 10 may be substantially annular around a longitudinal axis X. Further, the combustion chamber 10 may comprise a radially inner annular wall 12 and a radially outer annular wall 13 which are coaxial with the axis corresponding to the longitudinal axis X of the combustion chamber 10. The radially inner annular walls 12 and radially outer annular walls 13 are connected at their upstream end by a bottom annular wall of chamber 11 which is in particular radial, with an axis coincident with the longitudinal axis X.
[0048] The hydrogen combustion device 100 comprises a combustion chamber 10 and at least one premixing chamber 24 having a first axis Y1 and an outlet 25 which opens into the combustion chamber 10. The outlet 25 of the premixing chamber 24 may in particular open into an inlet of the combustion chamber 10 and through the bottom annular chamber wall 11.
[0049] Further, the combustion device 100 comprises at least one first system 20 for injecting a mixture of hydrogen and air into the combustion chamber 10 along the first axis Y1. The first injection system 20 comprises the premixing chamber 24, primary means 21 for bringing air opening into the premixing chamber 24 and at least one first hydrogen inlet orifice 22 opening into the premixing chamber 24 along a direction which is shown as being substantially perpendicular to the first axis Y1 and downstream along the flow direction of the gases in the combustion device 100 from the primary air supplying means 21.
[0050] The flow direction of the gases in the combustion device 100 is shown by solid arrows in FIG. 1.
[0051] The angle between the direction of said at least one first orifice 22 and the first axis Y1 is advantageously included between 30° and 150°. The hydrogen flow therefore arrives substantially perpendicularly to the airflow coming from the primary means of bringing air into the premixing chamber, which serves to improve the homogeneity and speed of hydrogen and air mixing.
[0052] The combustion device 100 may preferably comprise a plurality of first injection systems 20 distributed annularly around the longitudinal axis X of the chamber bottom annular wall 11.
[0053] The combustion device 100 may further comprise a second or several second systems 30 for injecting hydrogen into the combustion chamber 10 along a second axis Y2. The second injection system 30 comprises at least one second hydrogen inlet orifice 31 opening into the combustion chamber 10.
[0054] The combustion device 100 may preferably comprise a plurality of second injection systems 30 distributed annularly around the longitudinal axis X of the chamber bottom annular wall 11.
[0055] On the one hand, said at least one first injection system 20 advantageously serves to provide a rapid and sufficiently homogeneous mixing of the air and hydrogen in the premixing chamber 24 before supplying the combustion chamber 10 with this mixture. On the other hand, said one second injection system 30 advantageously serves to stabilize the combustion process in the combustion chamber, in particular at low regime. Such a combustion device 100 thus allows development of a combustion that is both aerodynamically stable and weakly emitting of nitrogen oxides in the combustion chamber. Further, the combustion device according to the present disclosure has the advantage of being easily optimized, designed and produced.
[0056] Said at least one first injection system 20 may open into the combustion chamber 10 at the same longitudinal position as said at least one second injection system 30 along the longitudinal axis X.
[0057] Said at least one second injection system 30 may be arranged radially inward or radially outward from said at least one first injection system 20 along the first axis.
[0058] The second axis Y2 may be inclined radially inward compared to the first axis Y1.
[0059] Advantageously the premixing chamber 24 may be delimited on the outside by a cylindrical wall 241 in which said at least one first orifice 22 is formed.
[0060] Also, said at least one first orifice 22 corresponds in particular to a direct combustible injection orifice opening directly into the premixing chamber 24.
[0061] Said at least one second orifice 31 corresponds in particular to a direct injection orifice opening directly into the combustion chamber 10.
[0062] Said at least one first orifice 22 may comprise at least one annular row of first orifices 22, for example an annular row of first orifices 22 or alternatively a plurality of annular rows of first orifices 22 spaced longitudinally. The annular row of first orifices 22 advantageously serves to annularly distribute the hydrogen supply from the premixing chamber, and thus to improve the homogeneity of the hydrogen and air mixture in the premixing chamber 24.
[0063] Each annular row of first orifices 22 may comprise two first orifices 22, for example arranged diametrically opposite relative to the premixing chamber 24.
[0064] Said first orifices 22 of the annular row may be aligned circumferentially such that at least some of the first orifices 22, preferably all of the first orifices 22, are intercepted by a single plane perpendicular to the first axis Y1.
[0065] Said at least first injection system 20 may advantageously comprise an annular hydrogen supply ramp surrounding the premixing chamber 24 of said first injection system 20. Said annular ramp may in particular comprise at least one annular row of first orifices 22, preferably one annular row of first orifices 22. The annular ramp is then configured for supplying the premixing chamber 24 with hydrogen through the first orifices 22 of the annular row. With this configuration, the implementation of the annular row of first orifices may be easier.
[0066] The combustion device 100 may comprise means of bringing hydrogen connected to the first orifices 22 and the second orifices 31.
[0067] The means of bringing hydrogen may for example comprise a first annular hydrogen supply conduit connected to the ramp. The bringing means may also comprise an annular conduit whose downstream end is connected to said second orifices 31.
[0068] Each of said at least one first injection system 20 may comprise at least one micro-injector configured for propelling hydrogen micro-jets through said at least one first orifice 22 and into the premixing chamber 24.
[0069] Said at least one first orifice 22 may open into the premixing chamber 24, downstream from the primary means 21 for bringing air and ideally near it. This configuration serves to improve the efficiency of mixing hydrogen and air. In practice, said first orifice 22 is located immediately by the means of bringing air. The orifice 22 is therefore located in the first half of the premixing chamber.
[0070] Each of said at least one first orifice 22 may have a diameter included between 0.2 mm and 3 mm.
[0071] Each of said at least one second injection system 30 may comprise at least one micro-injector configured for propelling hydrogen micro-jets through said at least one second orifice 31 and into the combustion chamber 10.
[0072] Each of said at least one second orifice 31 may have a diameter included between 0.2 mm and 3 mm.
[0073] Further, the first injection system 20 may comprise secondary means 23 for bringing air opening into the premixing chamber 24 downstream from said at least one first orifice 22, preferably at a downstream end of the premixing chamber 24. These secondary means 23 for bringing air advantageously serve to limit the risk of backdraft from the combustion chamber 10 into the first injection system 20.
[0074] The secondary means 23 for bringing air may comprise at least one third orifice 231 opening into the premixing chamber 24 downstream from said at least one first orifice 22, preferably at a downstream end of the premixing chamber 24.
[0075] Said at least one third orifice 231 may be oriented radially inward and towards the downstream along the first axis Y1.
[0076] The first injection system 20 may advantageously comprise at least one annular row of third orifices 231, for example one annular row of third orifices 231. Each annular row of third orifices 231 may for example comprise two third orifices 231, preferably arranged diametrically opposite relative to the premixing chamber 24.
[0077] The two third orifices 231 may for example be arranged respectively radially inward and radially outward of the premixing chamber 24 relative to the longitudinal axis X.
[0078] Each of said at least one third orifice 231 may have a diameter included between 0.05 mm and 3 mm.
[0079] Advantageously, the primary means of bringing air may be configured for supplying the premixing chamber with swirling air. This characteristic serves to improve the control of the aerodynamics in the premixing chamber, by allowing a rapid and substantially homogeneous mixing of the air and the hydrogen in the premixing chamber.
[0080] The combustion device may comprise means for regulating the supply of hydrogen and air to the premixing chamber configured for implementing a poor hydrogen and air mixture in the premixing chamber. The premixing chamber is advantageously intended to receive this poor hydrogen and air mixture. “Poor” is understood to mean the air is in excess relative to the hydrogen in the premixing chamber. “Rich” is understood to mean that hydrogen is in excess relative to the air in the pre-mixing chamber. Combustion of the poor premixture advantageously serves to reduce the flame temperature in the combustion chamber, and thus to reduce the nitrogen oxides emitted.
[0081] The means for regulation of the hydrogen and air supply to the premixing chamber may in particular be configured for distributing a flow of air arriving into the premixing chamber between the primary means of bringing air and the secondary means of bringing air. The primary means of bringing air may in particular be configured for supplying the premixing chambers with air with a mass flow rate between two and five times greater than the mass flow rate of air brought by the secondary means.
Claims
1. A hydrogen combustion device (100) comprising:an annular combustion chamber (10) with longitudinal axis (X) and at least one premixing chamber (24) having a first axis (Y1) and an outlet (25) which opens into the combustion chamber (10);at least one first system (20) for injecting a mixture of hydrogen and air into the combustion chamber (10) along the first axis (Y1), where the first injection system (20) comprises the premixing chamber (24), primary means (21) of bringing air opening into the premixing chamber (24) and at least one first hydrogen inlet orifice (22) opening into the premixing chamber (24) downstream in the flow direction of the gases in the combustion device (100) from the primary means (21) of bringing air;the first injection system (20) comprises secondary means (23) for bringing air opening into the premixing chamber (24) downstream from said at least one first orifice (22).
2. The combustion device according to claim 1, comprising at least one second system (30) for injecting hydrogen into the combustion chamber (10) along a second axis (Y2), where the second injection system (30) comprises at least one second hydrogen inlet orifice (31) opening into the combustion chamber (10).
3. The combustion device (100) according to claim 1, wherein said at least one first orifice (22) comprises at least one annular row of first orifices (22).
4. The combustion device (100) according to claim 3, wherein said first orifices (22) of the annular row are aligned circumferentially such that at least some of the first orifices (22), preferably all of the first orifices (22), are intercepted by a single plane perpendicular to the first axis (Y1).
5. The combustion device (100) according to claim 1, wherein said at least first injection system (20) comprises an annular hydrogen supply ramp surrounding the premixing chamber (24) of said first injection system (20).
6. The combustion device (100) according to claim 2, wherein the second axis (Y2) is inclined radially inward compared to the first axis (Y1).
7. The combustion device (100) according to claim 2, wherein the secondary means (23) for bringing air may comprise at least one third orifice (231) formed at a downstream end of the premixing chamber (24).
8. The combustion device (100) according to claim 7, wherein said at least one third orifice (231) may be oriented radially inward and towards the downstream along the first axis (Y1).
9. The combustion device (100) according claim 1, wherein the premixing chamber (24) is delimited on the outside by a cylindrical wall (241) in which said at least one first orifice (22) is formed.
10. The combustion device (100) according to claim 1, wherein the outlet (25) of the premixing chamber (24) opens at the inlet of the annular combustion chamber (10) and through a chamber bottom annular wall (11) of the annular combustion chamber (10).
11. The combustion device (100) according to claim 1, comprising a plurality of first injection systems (20) distributed annularly around the longitudinal axis (X).
12. The combustion device according to claim 1, wherein said at least one first hydrogen inlet orifice opens into the premixing chamber along a direction forming an angle included between 30° and 150° with the first axis.
13. A turbomachine comprising the combustion device (100) according to claim 1.