Hydrogen combustion device
Patent Information
- Application Number
- EP2023841009
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-20
- Filing Date
- 2023-12-18
- Publication Date
- 2025-10-29
AI Technical Summary
Conventional hydrogen combustion in turbomachines results in high-temperature diffusion flames, flame flashbacks, and high nitrogen oxide emissions, which pose challenges for the combustion chamber's thermal load and stability.
A hydrogen combustion device featuring a premixing chamber with a primary air supply and strategically oriented hydrogen inlets for efficient mixing, along with an optional secondary hydrogen injection system, stabilizes combustion and reduces nitrogen oxide emissions by promoting homogeneous mixing and lean fuel-air ratios.
The device achieves stable, aerodynamically controlled combustion with reduced nitrogen oxide emissions, enhancing the durability and efficiency of the combustion process while being easily optimized and manufactured.
Smart Images
Figure 1.1
Abstract
Description
Description Title: Hydrogen combustion device Technical field
[0001] The present disclosure relates to the field of combustion such as in particular hydrogen for a turbine, in particular for a turbomachine, such as for example a gas turbine, a turbojet or an aircraft turboprop. More specifically, the present disclosure relates to a hydrogen combustion device. Prior art
[0002] An aircraft turbomachine typically includes a combustion chamber fueled by kerosene. However, in order to reduce environmental impact and pollutant emissions and contribute to the decarbonization of air transport, consideration has been given to replacing kerosene with a hydrogen-based fuel.
[0003] In order to enable stable combustion from hydrogen, it is known to generate diffusion flames in the combustion chamber, i.e. flames which are obtained from reactants which are very little mixed with air, or even not mixed at all, before arriving in the combustion chamber.
[0004] However, these diffusion flames resulting from hydrogen combustion reach higher temperatures than flames resulting from kerosene combustion under equivalent thermodynamic and richness conditions. "Richness" refers to the proportion of hydrogen to air for combustion. The mixture is said to be "rich" when hydrogen is in excess compared to air, and conversely, the mixture is said to be "lean" when air is in excess compared to hydrogen. The combustion chamber must then be able to withstand these high temperatures.
[0005] Furthermore, the flame speeds resulting from hydrogen combustion are higher than those resulting from kerosene combustion. These high flame speeds can generate flashbacks in the fuel injection systems in the combustion chamber. These flashbacks can therefore damage the injection systems.
[0006] In addition, the temperatures produced by the combustion of hydrogen are high emitters of nitrogen oxides (NOx).
[0007] Therefore, there is a need to develop hydrogen combustion devices that allow stable combustion with low nitrogen oxide emissions, limiting the thermal load on the combustion devices and the risks of flashback.
[0008] This document aims to provide a simple, reliable and economical solution to this need. Summary
[0009] A hydrogen combustion device is proposed comprising: - a combustion chamber and at least one premixing chamber having a first axis and an outlet which opens into the combustion chamber, - at least one first system for injecting a mixture of hydrogen and air into the combustion chamber along the first axis, the first injection system comprising the premixing chamber, primary air supply means opening into the premixing chamber and at least one first hydrogen inlet opening opening into the premixing chamber downstream of the primary air supply means along the direction of flow of the gases in the combustion device, - optionally, at least one second system for injecting hydrogen into the combustion chamber along a second axis, the second injection system comprising at least one second hydrogen inlet opening opening into the combustion chamber.
[0010] In a particular embodiment, said at least one first hydrogen inlet orifice opens into the premixing chamber in a direction forming an angle of between 30° and 150° with the first axis. This orientation of the hydrogen flow coming from the primary air supply means into the premixing chamber makes it possible to improve the homogeneity and speed of the mixing of hydrogen and air. In a particular embodiment, the angle may be 90°.
[0011] On the one hand, said at least first injection system advantageously makes it possible to ensure 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 makes it possible to stabilize the combustion process in the combustion chamber, in particular at low speed. Such a combustion device thus allows the development of combustion that is both aerodynamically stable and emits low amounts of nitrogen oxides in the combustion chamber. Furthermore, the combustion device according to the present disclosure retains the advantage of being able to be easily optimized, designed and manufactured.
[0012] The features set out in the following paragraphs may, optionally, be implemented independently of each other or in combination with each other.
[0013] Said at least one first orifice corresponds in particular to a premixing orifice opening directly into the premixing chamber. In addition, said optional second orifice corresponds in particular to a direct injection orifice, opening directly into the combustion chamber.
[0014] 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 makes it possible to distribute the supply annularly in hydrogen from the premixing chamber, and thus improve the homogeneity of the hydrogen and air mixture in the premixing chamber.
[0015] Each annular row of first orifices may comprise two first orifices, for example arranged diametrically opposite relative to the premixing chamber.
[0016] Said first orifices of the annular row can be circumferentially aligned so that at least some of the first orifices, preferably all of the first orifices, are intercepted by the same plane perpendicular to the first axis.
[0017] 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 an annular row of first orifices. The annular ramp is then configured to supply hydrogen to the premixing chamber through the first orifices of the annular row. This configuration makes it easier to implement the annular row of first orifices.
[0018] Each of said at least one first injection system may comprise at least one micro-injector configured to project into the premixing chamber a micro-jet of hydrogen by injection through said at least one first orifice.
[0019] Said at least one first orifice must open into the premixing chamber along the first axis, downstream of the primary air supply means and ideally close to it. This configuration makes it possible to improve the efficiency of the hydrogen and air mixture.
[0020] The premixing chamber can advantageously be delimited externally by a cylindrical wall in which said at least one first orifice is formed.
[0021] Each of said at least one first orifice may have a diameter of between 0.2 mm and 3 mm.
[0022] Each of said at least one second injection system may comprise at least one micro-injector configured to project micro-jets of hydrogen through said at least one second orifice and into the combustion chamber.
[0023] Each of said at least one second orifice may have a diameter of between 0.2 mm and 3 mm.
[0024] Advantageously, the primary air supply means may be configured to supply the premixing chamber with swirl air, commonly referred to as “swirl” in English. This feature makes it possible to improve the control of aerodynamics in the premixing chamber, and to promote rapid and substantially homogeneous mixing of the air and hydrogen in the premixing chamber.
[0025] Advantageously, the first injection system may comprise secondary air supply means opening into the premixing chamber downstream of said at least one first orifice, preferably at a downstream end of the premixing chamber. These supply means air advantageously limits the risk of flame rising in the premixing chamber.
[0026] The secondary air supply means may comprise at least one third orifice opening into the premixing chamber downstream of said at least one first orifice, preferably at a downstream end of the premixing chamber.
[0027] Said at least one third orifice can be oriented radially inwards and downstream along the first axis.
[0028] The first injection system may advantageously comprise at least one annular row of third orifices, for example an 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 inside and radially outside the premixing chamber relative to a longitudinal axis of the combustion chamber.
[0029] Each of said at least one third orifice may have a diameter of between 0.05 mm and 3 mm.
[0030] Furthermore, the combustion chamber can be annular or tubular.
[0031] The combustion chamber may comprise an annular chamber bottom wall with an axis merging with the longitudinal axis or a set of tubular chambers, not necessarily parallel in direction, distributed around the longitudinal axis.
[0032] Said at least one first injection system can open into the combustion chamber at the same longitudinal position as said at least one second injection system along the longitudinal axis.
[0033] Said at least one second injection system can be arranged radially inside or radially outside said at least one first injection system along the first axis.
[0034] The second axis may be inclined radially inward relative to the first axis.
[0035] Advantageously, for a combustion chamber with annular geometry, the outlet of the premixing chamber opens at the inlet of the combustion chamber and through the annular bottom wall of the combustion chamber.
[0036] The combustion device may comprise a plurality of first injection systems distributed annularly around the longitudinal axis of the combustion chamber.
[0037] The combustion device may comprise a plurality of second injection systems distributed annularly around the longitudinal axis of the combustion chamber.
[0038] The combustion device may comprise means for regulating the supply of hydrogen and air to the premixing chamber configured to produce a lean mixture of hydrogen and air in the premixing chamber. The premixing chamber is advantageously intended to receive this lean mixture of hydrogen and air. "Lean" means that the air is in excess compared to the hydrogen in the premixing chamber. Conversely, "rich" means that the hydrogen is in excess compared to the air, with respect to the stoichiometry. The combustion of the lean premix advantageously makes it possible to reduce the flame temperature in the combustion chamber, and thus to reduce nitrogen oxide emissions.
[0039] The means for regulating the supply of hydrogen and air to the premixing chamber may in particular be configured to distribute a flow of air arriving in the premixing chamber between the primary air supply means and the secondary air supply means. The primary air supply means may in particular be configured to supply the premixing chamber with air with a mass flow rate between two and fifty times greater than a mass flow rate of air supplied by the secondary means.
[0040] According to another aspect, there is provided a turbomachine comprising the combustion device as previously described. Brief description of the drawings
[0041] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Fig. 1
[0042] [Fig. 1] schematically illustrates a partial sectional view of a combustion device according to the present disclosure. Fig. 2
[0043] [Fig. 2] schematically illustrates another partial sectional view of the combustion device according to the present disclosure. Description of the embodiments
[0044] Reference is now made to Figures 1 and 2 schematically representing respectively partial sectional views of examples of hydrogen combustion device 100 according to the present document. The combustion device 100 can be implemented in a gas turbine, or a turbomachine, for example a turboprop, or an aircraft turbojet.
[0045] The combustion chamber 10 may be substantially annular around a longitudinal axis X. In addition, the combustion chamber 10 may comprise a radially internal annular wall 12 and a radially external annular wall 13 coaxial with an axis corresponding to the longitudinal axis X of the combustion chamber 10. The radially internal 12 and external 13 annular walls are connected at their upstream end by an annular chamber bottom wall 11, which is in particular radial, with an axis merging with the longitudinal axis X.
[0046] 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 can in particular open at the inlet of the combustion chamber 10 and through the annular bottom wall of the chamber 11.
[0047] In addition, the combustion device 100 comprises at least a first injection system 20 of 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 air supply opening into the premixing chamber 24 and at least one first hydrogen supply orifice 22 opening into the premixing chamber 24 in a direction which is represented as being substantially perpendicular to the first axis Y1 and downstream of the primary air supply means 21 in the direction of flow of the gases in the combustion device 100.
[0048] The direction of flow of gases in the combustion device 100 is represented by solid arrows in FIG. 1.
[0049] The angle between the direction of said at least one first orifice 22 and the first axis Y1 is advantageously between 30° and 150°. The hydrogen flow therefore arrives substantially perpendicular to the air flow coming from the primary air supply means into the premixing chamber, which makes it possible to improve the homogeneity and speed of the mixing of hydrogen and air.
[0050] The combustion device 100 may preferably comprise a plurality of first injection systems 20 distributed annularly around the longitudinal axis X of the annular chamber bottom wall 11.
[0051] The combustion device 100 may further comprise a second or more second hydrogen injection systems 30 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.
[0052] The combustion device 100 may preferably comprise a plurality of second injection systems 30 distributed annularly around the longitudinal axis X of the annular chamber bottom wall 11.
[0053] On the one hand, said at least one first injection system 20 advantageously makes it possible to ensure 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 makes it possible to stabilize the combustion process in the combustion chamber, in particular at low speed. Such a combustion device 100 thus allows the development of a combustion that is both aerodynamically stable and emits low amounts of nitrogen oxides in the combustion chamber. In addition, the The combustion device according to the present disclosure has the advantage of being easily optimized, designed and manufactured.
[0054] Said at least one first injection system 20 can 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.
[0055] Said at least one second injection system 30 can be arranged radially inside or radially outside said at least one first injection system 20 along the first axis.
[0056] The second axis Y2 can be inclined radially inward relative to the first axis Y1.
[0057] The premixing chamber 24 can advantageously be delimited externally by a cylindrical wall 241 in which said at least one first orifice 22 is formed.
[0058] Furthermore, said at least one first orifice 22 corresponds in particular to a direct fuel injection orifice opening directly into the premixing chamber 24.
[0059] Said at least one second orifice 31 corresponds in particular to a direct injection orifice, opening directly into the combustion chamber 10.
[0060] 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 makes it possible to distribute the hydrogen supply to the premixing chamber annularly, and thus to improve the homogeneity of the mixture of hydrogen and air in the premixing chamber 24.
[0061] Each annular row of first orifices 22 may comprise two first orifices 22, for example arranged diametrically opposite relative to the premixing chamber 24.
[0062] Said first orifices 22 of the annular row can be circumferentially aligned so that at least some of the first orifices 22, preferably all of the first orifices 22, are intercepted by the same plane perpendicular to the first axis Y1.
[0063] 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 an annular row of first orifices 22. The annular ramp is then configured to supply hydrogen to the premixing chamber 24 through the first orifices 22 of the annular row. This configuration makes it easier to implement the annular row of first orifices.
[0064] The combustion device 100 may comprise hydrogen supply means connected to the first orifices 22 and to the second orifices 31.
[0065] The hydrogen supply means may for example comprise a first annular hydrogen supply pipe connected to the ramp. The supply means may also comprise an annular pipe whose downstream end is connected to said second orifices 31.
[0066] Each of said at least one first injection system 20 may comprise at least one micro-injector configured to project micro-jets of hydrogen through said at least one first orifice 22 and into the premixing chamber 24.
[0067] Said at least one first orifice 22 can open into the premixing chamber 24 downstream of the primary air supply means 21 and ideally close to it. This configuration makes it possible to improve the efficiency of the mixture of hydrogen and air. In practice, said first orifice 22 is located in the immediate vicinity of the air supply means. The orifice 22 is therefore located in the first half of the premixing chamber.
[0068] Each of said at least one first orifice 22 may have a diameter of between 0.2 mm and 3 mm.
[0069] Each of said at least one second injection system 30 may comprise at least one micro-injector configured to project micro-jets of hydrogen through said at least one second orifice 31 and into the combustion chamber 10.
[0070] Each of said at least one second orifice 31 may have a diameter of between 0.2 mm and 3 mm.
[0071] Furthermore, the first injection system 20 may advantageously comprise secondary air supply means 23 opening into the premixing chamber 24 downstream of said at least one first orifice 22, preferably at a downstream end of the premixing chamber 24. These secondary air supply means 23 advantageously make it possible to limit the risk of flame rising from the combustion chamber 10 into the first injection system 20.
[0072] The secondary air supply means 23 may comprise at least one third orifice 231 opening into the premixing chamber 24 downstream of said at least one first orifice 22, preferably at a downstream end of the premixing chamber 24.
[0073] Said at least one third orifice 231 can be oriented radially inwards and downstream along the first axis Y1.
[0074] The first injection system 20 may advantageously comprise at least one annular row of third orifices 231, for example an 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.
[0075] The two third orifices 231 can for example be arranged respectively radially inside and radially outside the premixing chamber 24 relative to the longitudinal axis X.
[0076] Each of said at least one third orifice 231 may have a diameter of between 0.05 mm and 3 mm.
[0077] Advantageously, the primary air supply means may be configured to supply the premixing chamber with swirl air, commonly referred to as “swirl” in English. This feature improves control of the aerodynamics in the premixing chamber, and allows rapid and substantially homogeneous mixing of the air and hydrogen in the premixing chamber.
[0078] The combustion device may comprise means for regulating the supply of hydrogen and air to the premixing chamber, configured to produce a lean mixture of hydrogen and air in the premixing chamber. The premixing chamber is advantageously intended to receive this lean mixture of hydrogen and air. “Lean” means that the air is in excess relative to the hydrogen in the premixing chamber. Conversely, “rich” means that the hydrogen is in excess relative to the air, with respect to the stoichiometry. The combustion of the lean premix advantageously makes it possible to reduce the flame temperature in the combustion chamber, and thus to reduce nitrogen oxide emissions.
[0079] The means for regulating the supply of hydrogen and air to the premixing chamber may in particular be configured to distribute a flow of air arriving in the premixing chamber between the primary air supply means and the secondary air supply means. The primary air supply means may in particular be configured to supply the premixing chamber with air with a mass flow rate between two and fifty times greater than a mass flow rate of air supplied by the secondary means.
Claims
Claims
1. A hydrogen combustion device (100) comprising: - an annular combustion chamber (10) with a 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 injection 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) comprising the premixing chamber (24), primary air supply means (21) opening into the premixing chamber (24) and at least one first hydrogen inlet orifice (22) opening into the premixing chamber (24) downstream of the primary air supply means (21) along the direction of flow of the gases in the combustion device (100), the first injection system (20) comprising secondary air supply means (23) opening into the premixing chamber (24) downstream of said at least one first orifice (22).
2. Device according to claim 1, comprising at least a second system (30) for injecting hydrogen into the combustion chamber (10) along a second axis (Y2), the second injection system (30) comprising at least a second orifice (31) for the arrival of hydrogen opening into the combustion chamber (10).
3. A combustion device (100) according to claim 1 or 2, wherein said at least one first orifice (22) comprises an annular row of first orifices (22).
4. Combustion device (100) according to claim 3, wherein said first orifices (22) of the annular row are circumferentially aligned so that at least some of the first orifices (22), preferably all of the first orifices (22), are intercepted by the same plane perpendicular to the first axis (Y1).
5. Combustion device (100) according to one of claims 1 to 4, 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. Combustion device (100) according to one of claims 1 to 5 and claim 2, wherein the second axis (Y2) is inclined radially inwards relative to the first axis (Y1).
7. Combustion device (100) according to one of the preceding claims, in which the secondary air supply means (23) comprise at least one third orifice (231) formed at a downstream end of the premixing chamber (24). [Claim s] Combustion device (100) according to claim 7, wherein said at least one third orifice (231) is oriented radially inward and downstream along the first axis (Y1).
9. Combustion device (100) according to one of claims 1 to 8, in which the premixing chamber (24) is delimited externally by a cylindrical wall (241) in which said at least one first orifice (22) is formed.
10. Combustion device (100) according to one of claims 1 to 9, in which the outlet (25) of the premixing chamber (24) opens at the inlet of the annular combustion chamber (10) and through an annular bottom wall of the chamber (11) of the annular combustion chamber (10).
11. Combustion device (100) according to one of the preceding claims, comprising a plurality of first injection systems (20) distributed annularly around the longitudinal axis (X).
12. Combustion device according to one of claims 1 to 11, in which said at least one first hydrogen inlet orifice opens into the premixing chamber in a direction forming an angle with the first axis of between 30° and 150°.
13. Turbomachine comprising the combustion device (100) according to one of claims 1 to 12.