Multi-fuel combustion chamber head and control method of multi-fuel combustion chamber

Abstract

A multi-fuel combustor head permits hydrogen-doped or pure hydrogen combustion in some operating conditions. According to the control method of the multi-fuel combustion chamber, a low-pollution and low-carbon combustion organization form can be achieved. The multi-fuel combustion chamber head comprises a duty stage, the duty stage comprises a first air flow channel and a liquid fuel pipe, air provided by the first air flow channel and liquid fuel provided by the liquid fuel pipe are mixed in a pre-mixing space, and a second air flow channel extends on the periphery of the pre-mixing space, an outlet is located in the downstream side of the premixing space, a swirler is omitted in the second air flow channel, and an air supercharging device is arranged in the second air flow channel so that air can flow out of the outlet in an accelerated mode; the hydrogen distribution pipe comprises a plurality of spraying holes, and the spraying holes are arranged in a transverse spraying mode on the downstream of an outlet of the second air flow channel relative to the air flowing direction of the second air flow channel.

Description

Technical Field

[0001] The invention relates to a combustion chamber, and in particular to a combustion chamber head of a gas turbine or an aircraft engine and a combustion control method of the combustion chamber. Background Art

[0002] The increase in environmental awareness has made the reduction of pollutant emissions during the combustion process one of the main challenges in the development of aircraft engines. In order to obtain lower NOx emissions without increasing the concentration of exhaust carbon monoxide and unburned hydrocarbons, low-emission combustion forms such as lean oil premixing preevaporation and rich oil quenching lean oil combustion have been widely studied and applied in gas turbines and aircraft engines. However, with the proposal of the carbon neutrality goal, the exhaust emissions based on hydrocarbon fuels always contain CO2, which cannot meet the requirements of low-carbon combustion. Recently, combustion organization forms based on sustainable fuels and other fuels have been widely studied in aircraft engine combustors, with the main purpose of further reducing carbon emissions while reducing traditional pollutant emissions (such as NOx).

[0003] Hydrogen combustion is one of the most environmentally friendly combustion organization methods. It has no problems of combustion carbon emissions and other combustion pollution products, and is a low-carbon fuel with great potential. However, hydrogen combustion also has problems such as storage difficulties, high transportation costs per unit volume, too fast combustion speed, and high flame temperature, which brings challenges to how to reasonably organize combustion in the combustion chamber of an aircraft engine. At the same time, due to factors such as the cost and risk of redeveloping a new combustion chamber, traditional liquid fuels and sustainable fuels will remain the main fuels for aircraft engines for a long time. Therefore, designing a multi-fuel aircraft engine combustion chamber that burns liquid fuel and hydrogen at the same time can not only effectively reduce carbon emissions and pollutant products, but also utilize the existing mature combustion chamber geometry to reduce the cost and risk of designing a new combustion chamber. Summary of the invention

[0004] The object of the present invention is to provide a multi-fuel combustion chamber head that allows hydrogen-blended or pure hydrogen combustion under certain operating conditions.

[0005] Another object of the present invention is to provide a control method for a multi-fuel combustion chamber to achieve a low-pollution and low-carbon combustion organization form.

[0006] According to one aspect of the present invention, a multi-fuel combustion chamber head includes a duty class, which includes a first air flow channel and a liquid fuel pipe, wherein the air provided by the first air flow channel and the liquid fuel provided by the liquid fuel pipe are mixed in a premixing space, and wherein a second air flow channel extends around the periphery of the premixing space, and an outlet is located on the downstream side of the premixing space, a swirler is eliminated in the second air flow channel, and an air booster device is provided to accelerate the outflow of air from the outlet; the hydrogen distribution pipe includes a plurality of spray holes, and the spray holes are arranged to spray horizontally downstream of the outlet of the second air flow channel relative to the air flow direction of the second air flow channel.

[0007] In one embodiment, the air boosting device comprises a boosting section of the second air flow channel and a plurality of air baffles. The boosting section of the second air flow channel extends to the outlet, and the cross-sectional area of ​​the flow channel decreases along the air flow direction; and the plurality of air baffles are circumferentially spaced in the boosting section.

[0008] In one embodiment, the premixing space is defined by an inner surface of the venturi.

[0009] In one embodiment, the two air baffles and the one spray hole are arranged in one-to-one correspondence, so that the airflow passing through the two air baffles is accelerated to flow through the corresponding spray holes.

[0010] In one embodiment, the distance between the nozzle hole and the end wall facing the flame chamber is 1-5 mm.

[0011] In one embodiment, the distance between the nozzle hole and the end wall of the structure defining the premixing space is 1-5 mm.

[0012] In one embodiment, the liquid fuel pipe is connected to a centrifugal nozzle, which is used to generate liquid mist from the liquid fuel and make the liquid mist hit the wall of the premixing space to form a liquid film. The first air flow channel is provided with a swirler to fully mix the air with the atomized liquid fuel.

[0013] According to another aspect of the present invention, a method for controlling a multi-fuel combustion chamber comprises the following steps:

[0014] Providing a multi-fuel combustor, the multi-fuel combustor comprising any of the multi-fuel combustor heads, the multi-fuel combustor head also comprising a main combustion stage surrounding the duty stage;

[0015] When the combustion chamber is ignited, only the flame is on duty. In order to improve the ignition performance of the combustion chamber, hydrogen-blended or pure hydrogen combustion is used;

[0016] When the engine is in low thrust condition, it only operates on duty and uses hydrogen-blended or pure hydrogen combustion;

[0017] When the engine is in medium and high thrust conditions, the duty class and main combustion stage flames are turned on at the same time. The duty class flame uses pure hydrogen or hydrogen-blended combustion, and the main combustion stage flame uses pure liquid combustion.

[0018] According to the embodiment of the present invention, hydrogen is introduced into the duty class of the combustion chamber to achieve staged combustion of hydrogen-blended / pure hydrogen combustion in the duty class and liquid fuel combustion in the main combustion class. The combustion chamber equivalence ratio and fuel distribution can be flexibly changed to adjust to form a stable combustion with low pollution and low carbon. This method is different from the traditional radial staged combustion, which is characterized by liquid fuel. By eliminating the swirler in the air flow channel where the hydrogen cross-jet flow is located and setting an air baffle, the mixing of hydrogen and air is accelerated, the risk of flashback is reduced, and hydrogen-blended / pure hydrogen combustion in the duty class is formed. Existing liquid fuels such as aviation kerosene and other sustainable alternative fuels are used to form the main combustion flame, achieving a low-pollution and low-carbon combustion organization. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0020] Figure 1 is a schematic diagram of a multi-fuel combustor.

[0021] Figure 2 is a cross-sectional view of the head of a multi-fuel combustor.

[0022] Figure 3 It is a three-dimensional view of the head of the multi-fuel combustor.

[0023] Figure 4 It is a three-dimensional image of the duty class at the head of the multi-fuel combustor. DETAILED DESCRIPTION

[0024] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0025] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of the respective components.

[0026] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0027] like Figure 1 As shown, the multi-fuel combustion chamber includes a combustion chamber head 34, which includes a duty stage located in the center and a main combustion stage arranged around the duty stage to form radial staged combustion, that is, using air or fuel to form a regional combustion organization at different radial spatial positions. By adopting staged combustion, the ratio of duty stage and main combustion stage fuel can be flexibly adjusted according to different working conditions of the aircraft engine.

[0028] like Figure 2 As shown, the duty class includes a first air flow channel 11 and a liquid fuel pipe 1. The air provided by the first air flow channel 11 and the liquid fuel provided by the liquid fuel pipe 1 are mixed in the premixing space 16. The duty class also includes a second air flow channel 12 and a hydrogen distribution pipe 3. The second air flow channel 12 extends on the periphery of the premixing space 16, and the outlet is located on the downstream side of the premixing space 16. The swirler is eliminated in the second air flow channel 12 and an air booster device is provided to accelerate the air to flow out from the outlet. The hydrogen distribution pipe 3 is connected to the spray hole 4. The spray hole 4 is arranged to spray horizontally downstream of the outlet of the second air flow channel 12 relative to the air flow direction of the second air flow channel 12. In the following content here, the air flow channel is an annular structure in the combustion chamber head, and the pipe is an elongated cylindrical structure in the combustion chamber head.

[0029] like Figure 1 As shown, after air 21 passes through the diffuser and enters the combustion chamber, part of the air 24 enters the combustion chamber head to directly participate in the combustion, part of the air 22 flows through the inner ring cavity of the combustion chamber to form cooling air 25, and part of the air 23 flows through the outer ring cavity of the combustion chamber to form cooling air 25. Part of the cooling air 25 enters the flame tube to cool the flame tube wall, and then flows to the downstream high-pressure turbine together with the high-temperature combustion gas 26. Figure 2As shown, the air 24 entering the head of the combustion chamber is divided into the duty class air 7 entering the duty class and the main combustion stage air 8 entering the main combustion stage. The duty class air 7 is divided into two streams, one of which flows through the first air flow channel 11 and enters the premixing space 16, and this air is mixed with the fuel supplied by the liquid fuel pipe 1. The other air enters the air flow channel 12 without a swirler, is accelerated by the air booster device, and is mixed with the hydrogen ejected from the downstream nozzle 4. By eliminating the swirler in the air flow channel where the hydrogen cross-jet flow is located and providing an air booster device, the mixing of hydrogen and air is accelerated, the risk of flashback is reduced, and pure hydrogen combustion can be formed. During hydrogen-blended combustion, in the duty class, on the one hand, the hydrogen in the hydrogen distribution pipe 3 is mixed with the air in the second air flow channel 12 and enters the combustion chamber; on the other hand, the air passing through the swirler 10 is mixed with the liquid mist 6 generated by the centrifugal nozzle 32 and enters the combustion chamber. The mixed gases from these two aspects are mixed to a certain extent between the end faces 14 and 15, and will be further mixed downstream. At this time, the duty class flame is a mixed flame containing a hydrogen cross jet and a liquid fuel centrifugal nozzle, forming a low-carbon emission duty class flame.

[0030] An embodiment of the air boosting device includes a boosting section of the second air flow channel 12, such as Figure 2 As shown, the boosting section extends upward to the outlet of the second air flow channel 12, and the cross-sectional area of ​​the flow channel decreases along the airflow direction. The air boosting device also includes a plurality of air baffles 33, which are circumferentially spaced and distributed in the boosting section. The boosting section and the air baffles 33 together compress the airflow and thus boost the pressure by limiting the flow cross-sectional area of ​​the flow channel.

[0031] Continue to refer to Figure 2 The premixing space 16 is defined by the inner surface of the venturi tube. The effect of the venturi tube on the fluid being first pressurized and then depressurized is beneficial to the full mixing of the liquid fuel and the air.

[0032] In a preferred embodiment, two air baffles 33 and one spray hole 4 are arranged in a one-to-one correspondence, so that the airflow passing through the two air baffles 33 is accelerated to flow through the corresponding spray holes 4, thereby improving the air pressurization effect. Figure 3 and Figure 4 As shown, the air baffles 33 and the spray holes 4 are arranged in an annular shape, so the number of the air baffles 33 can be set to be the same as the spray holes 4, and the air baffles 33 are deflected at an angle in the circumferential direction relative to the spray holes 4, or the two are staggered in the circumferential direction.

[0033] In one embodiment, the distance between the nozzle hole 4 and the end wall 15 facing the flame chamber is 1-5 mm.

[0034] In yet another embodiment, the distance between the nozzle hole 4 and the end wall of the structure defining the premixing space 16 is 1-5 mm. Figure 2In the embodiment, the distance between the nozzle hole 4 and the end wall 14 of the venturi is 1-5 mm.

[0035] In a more specific embodiment, the diameter of the holes of the nozzle 4 is 0.3-2 mm, the number of holes is 12-60, and they are evenly arranged along the circumference of the wall of the value class.

[0036] Continue to refer to Figure 2 The liquid fuel pipe 1 is connected to the centrifugal nozzle 32, which is used to make the liquid fuel produce liquid mist 6, and make the liquid mist 6 hit the wall of the premixing space 16 to form a liquid film. The first air flow channel 11 is provided with a swirler 10 to fully mix the air with the atomized liquid fuel.

[0037] The swirler 10 is preferably a swirler with a high swirl number, for example, a swirl number greater than 0.7, so as to form a stronger velocity shear in the recirculation zone, allowing the air and liquid fuel to be fully mixed.

[0038] like Figure 1 As shown, the fuel pipe 29 contains two fuels: a liquid fuel delivery pipe 30 and a hydrogen fuel delivery pipe 31. The liquid fuel in the pipe 30 passes through the fuel pipe 1 and enters the centrifugal nozzle 32 of the duty class to generate liquid mist 6. The liquid mist 6 hits the venturi wall 16 to form a liquid film. The liquid film is sheared by the swirl of the first air flow channel 11 and the air flow of the second air flow channel 12 at the outlet end face 14 of the venturi, and gradually breaks into liquid filaments from the liquid film, and then further breaks into small droplets. The hydrogen in the pipe 31 enters the hydrogen transverse spray hole 4 through the hydrogen distribution pipe 3, and the generated hydrogen transverse jet 18 is further mixed with the droplet group 17 at the downstream of the duty class and enters the combustion chamber to form the duty class flame 28.

[0039] The main combustion air 8 passes through the main combustion swirler 9, is fully mixed with the liquid fuel produced by the horizontal fuel injection nozzle 5, and enters the combustion chamber. The liquid fuel in the pipe 30 passes through the fuel pipe 2, enters the main combustion nozzle 5, forms a horizontal liquid mist jet 19, hits the wall 13, and is fully mixed with the main combustion air in the main combustion channel 20, and enters the combustion chamber to form a main combustion flame 27. Since the main combustion fuel is mixed with the air in the main combustion channel through the liquid horizontal jet, it is conducive to forming a lean and low-pollution main combustion flame.

[0040] In one embodiment, the diameter of the main combustion stage spray holes 5 is 0.5-2 mm, the number of holes is 12-24, they are evenly arranged along the circumference of the main combustion stage air flow channel, and the distance from the burner outlet end face 15 is 5-15 mm.

[0041] The duty centrifugal nozzle and the main combustion fuel can be conventional aviation kerosene or other sustainable alternative fuels. The hydrogen passing through the hydrogen distribution pipe 3 can be pure hydrogen or a fuel rich in hydrogen.

[0042] like Figure 1 and Figure 2As shown, the duty class flame 27 formed by the mixture of duty class hydrogen 18 and liquid fuel 17 is in the middle of the combustion chamber. According to different working conditions of the combustion chamber, the hydrogen blending ratio of the duty class flame can be flexibly adjusted. The duty class can be pure liquid fuel combustion or pure hydrogen combustion. The main combustion class flame 28 formed by the main combustion class fuel 19 is circumferential to the duty class flame 27. When only the duty class is turned on, the duty class can be hydrogen blended and pure hydrogen combustion, and the hydrogen blending mass ratio adjustment range is 0-100%. When the duty class and the main combustion class flame are turned on at the same time, the mass of hydrogen accounts for less than 25% of the total fuel mass. By flexibly adjusting the proportion of hydrogen and liquid fuel, the combustion chamber can avoid flashback, flameout and combustion oscillation, forming a low-carbon, low-pollution stable combustion.

[0043] In one embodiment, the control method of the multi-fuel combustion chamber meets the different operating conditions and emission requirements of the engine by flexibly adjusting the ratio of the duty class flame and the main combustion class flame. When the combustion chamber is ignited, only the duty class flame is turned on. In order to improve the ignition performance of the combustion chamber, hydrogen-blended or pure hydrogen combustion is adopted. When the engine is in a low thrust condition, the low condition includes the taxiing condition or the condition with a thrust similar to that required by this condition, the combustion chamber only turns on the duty class, and hydrogen-blended or pure hydrogen combustion can be adopted. When the engine is in a medium-to-large thrust condition, the medium-to-large thrust condition includes take-off, cruising, landing or the condition with a thrust similar to that required by these conditions, the duty class flame and the main combustion class flame are turned on at the same time, the duty class flame can use pure hydrogen or hydrogen-blended combustion, and the main combustion class flame is pure liquid combustion.

[0044] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A multi-fuel combustion chamber head, comprising a duty class, wherein the duty class comprises a first air flow channel and a liquid fuel pipe, wherein the air provided by the first air flow channel and the liquid fuel provided by the liquid fuel pipe are mixed in a premixing space, characterized in that: The duty class also includes: A second air flow channel extends at the periphery of the premixing space, and an outlet is located at the downstream side of the premixing space, a swirler is eliminated in the second air flow channel, and an air booster device is provided to accelerate the air to flow out from the outlet; and A hydrogen distribution pipe comprises a plurality of spray holes, wherein the spray holes are arranged downstream of the outlet of the second air flow channel to spray laterally relative to the air flow direction of the second air flow channel.

2. The multi-fuel combustor head according to claim 1, characterized in that: The air boosting device comprises: A pressurizing section of the second air flow channel extends to the outlet, and the cross-sectional area of ​​the flow channel decreases along the air flow direction; and A plurality of air baffles are circumferentially spaced apart and distributed in the boost section.

3. A multi-fuel combustor head according to claim 1 or 2, characterized in that: The premixing space is defined by the inner surface of the venturi.

4. The multi-fuel combustor head according to claim 2, characterized in that: The two air baffles and the one spray hole are arranged in one-to-one correspondence, so that the airflow passing through the two air baffles is accelerated to flow through the corresponding spray holes.

5. The multi-fuel combustor head according to claim 1 or 2, characterized in that: The distance between the spray hole and the end wall facing the flame chamber is 1-5 mm.

6. A multi-fuel combustor head according to claim 1 or 2, characterized in that: The distance between the nozzle hole and the end wall of the structure defining the premixing space is 1-5 mm.

7. A multi-fuel combustor head according to claim 1 or 2, characterized in that: The liquid fuel pipe is connected to a centrifugal nozzle, which is used to generate liquid mist from the liquid fuel and make the liquid mist collide with the wall of the premixing space to form a liquid film. The first air flow channel is provided with a swirler to fully mix the air with the atomized liquid fuel.

8. A control method for a multi-fuel combustion chamber, characterized in that: include: Providing a multi-fuel combustor comprising a multi-fuel combustor head as claimed in any one of claims 1 to 7, the multi-fuel combustor head further comprising a main combustion stage surrounding the duty stage; When the combustion chamber is ignited, only the flame is on duty. In order to improve the ignition performance of the combustion chamber, hydrogen-blended or pure hydrogen combustion is used; When the engine is in low thrust condition, it only operates on duty and uses hydrogen-blended or pure hydrogen combustion; When the engine is in medium and high thrust conditions, the duty class and main combustion stage flames are turned on at the same time. The duty class flame uses pure hydrogen or hydrogen-blended combustion, and the main combustion stage flame uses pure liquid combustion.

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