Combustion chamber premix nozzle for hydrogen fuel gas turbine

Abstract

This invention provides a premixed nozzle for a hydrogen fuel cell gas turbine combustion chamber, comprising a film gas development channel, a fuel-air rapid mixing conduit, and a detachable nozzle lip. The fuel-air rapid mixing conduit, located at the center of the film gas development channel, is a hollow annular structure, and the two are connected via a fuel channel. When external air enters the film gas development channel from the bottom of the nozzle, it splits into two streams. One stream enters the fuel-air rapid mixing conduit and rapidly mixes with the fuel flowing through the fuel channel; the other stream continues to develop along the flow direction and eventually forms a film gas near the nozzle outlet, preventing backfire, raising the reaction zone, and improving the nozzle's safety and durability. The detachable nozzle lip adjusts the size of the local reaction zone near the lip by changing its thickness, thereby regulating the rise height of the reaction zone and suppressing thermoacoustic oscillations. This invention has a compact structure, flexible adjustment, and can rationally organize the rise height of the reaction zone and suppress thermoacoustic oscillations.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell combustion chamber technology, and more particularly to a premixing nozzle for a hydrogen fuel cell combustion chamber. Background Technology

[0002] To reduce carbon emissions from the power sector, burning low-carbon fuels such as high-hydrogen-content or even pure hydrogen is one measure for heavy-duty gas turbines to reduce greenhouse gas emissions. This requires gas turbines to be able to safely and stably use hydrogen-rich or even pure hydrogen fuels while maintaining high efficiency and not exceeding permissible pollutant emission levels. This poses a challenge to the retrofitting or redesign of traditional lean premixed gas turbine combustors that typically use natural gas as fuel, particularly in terms of fuel adaptability. Given the significant technical challenges of burning high-hydrogen-content or even pure hydrogen fuels, there are currently no feasible gas turbine combustors on the market that simultaneously meet the requirements of natural gas, high-hydrogen blending, or even pure hydrogen lean premixed fuels.

[0003] The main challenges of burning hydrogen fuel in gas turbines are: compared to traditional natural gas, hydrogen's higher flame propagation velocity and lower ignition delay time pose a risk of backfire; higher adiabatic flame temperatures lead to increased nitrogen oxide emissions; and hydrogen's unique fuel characteristics may result in significantly different stabilization mechanisms, altering its reaction zone morphology and causing changes in the flame's thermoacoustic response. Therefore, it is necessary to ensure low NOx emissions while maintaining high nitrogen oxide levels. x Under the premise of emission control, raising the height of the reaction zone can prevent backfire and improve the safety and durability of the nozzle. On the other hand, it can change the flow delay time from the fuel hole to the reaction zone, suppress thermoacoustic oscillation, and increase the safety and service life of the combustion chamber. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a premixed nozzle for a combustion chamber of a hydrogen fuel gas turbine, which can effectively prevent backfire, reduce nitrogen oxide emissions, and suppress thermoacoustic oscillations under hydrogen fuel combustion conditions, especially under high hydrogen content or even pure hydrogen combustion conditions, thereby achieving safe, stable, and low-emission combustion in hydrogen fuel gas turbines.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a premixed nozzle for a combustion chamber of a hydrogen fuel gas turbine, comprising: a film gas development channel, a fuel-air rapid mixing conduit, and a detachable nozzle lip edge; the fuel-air rapid mixing conduit is located at the center of the film gas development channel, and utilizes the gap between the two to rapidly develop an annular film gas to prevent backfire, thereby improving the safety of the combustion chamber nozzle; the detachable nozzle lip edge is located on one side of the fuel-air rapid mixing conduit, and is formed by a detachable collar with an inverted conical hole and a conical nozzle lip edge fixed on the nozzle, used to flexibly adjust the size of the local reaction zone according to the flow field organization requirements, thereby controlling the rise height of the reaction zone and suppressing thermoacoustic oscillations.

[0006] Preferably, the combustion chamber nozzle has an annular hollow structure. After the air enters from the bottom of the gas film development channel, it is divided into two streams. One stream enters the fuel-air rapid mixing duct and then rapidly mixes with the fuel entering the combustion chamber nozzle from the fuel channel.

[0007] Preferably, a single combustion chamber nozzle is provided with P fuel channels, which are connected to a fuel-air rapid mixing duct and a film gas development channel.

[0008] Preferably, the number P of fuel channels should satisfy P ≥ 3.

[0009] Preferably, the distance L1 between the center of the fuel passage and the outlet end face of the combustion chamber nozzle satisfies: 5D1 ≤ L1 ≤ 20D1, where D1 is the inner diameter of the combustion chamber nozzle outlet.

[0010] Preferably, the distance L2 between the outlet end face of the fuel-air rapid mixing duct and the outlet end face of the combustion chamber nozzle satisfies: 0 ≤ L2 ≤ 4D1.

[0011] Preferably, the radial distance L3 between the inner diameter of the gas film development channel outlet and the outer diameter of the fuel-air rapid mixing duct satisfies: 0.5 mm ≤ L3 ≤ 3 mm or L3 = 0 mm. When a gas film is required, the thickness of the gas film needs to be moderate. When a gas film is not required, the lifting height of the reaction zone can be finely adjusted solely by the edge of the detachable nozzle lip; in this case, L3 = 0 mm, and the gas film development channel coincides with the fuel-air rapid mixing duct.

[0012] Preferably, the angle between the outer wall of the conical spray nozzle lip and the line connecting the axis is θ1, satisfying... A detachable collar with an inverted conical hole has an angle θ2 between its outer side wall and the line connecting the axis, satisfying θ2 = θ1.

[0013] Preferably, the thickness of the detachable spray lip edge is L4, which satisfies: 0 mm ≤ L4 ≤ 5 mm.

[0014] This invention increases the rise in the reaction zone height during combustion of hydrogen-containing fuels, especially high-hydrogen-content fuels or even pure hydrogen fuels, by setting an annular gas film within the premixed nozzle, ensuring that there is no fuel near the boundary layer on the inner wall of the nozzle. This effectively prevents backfire. Furthermore, the detachable nozzle lip edge allows for adjustable lip thickness, altering the size of the local backflow zone near the lip edge and thus changing the rise characteristics of the combustion chamber reaction zone, thereby improving nozzle safety and durability. Additionally, changes in fuel flow delay time, particularly the distance from the nozzle outlet face to the reaction zone, can influence the thermoacoustic characteristics of the combustion chamber, suppressing thermoacoustic oscillations. The combustion chamber, composed of several nozzles, can organize the combustion chamber flow field according to fuel characteristics and, more importantly, flexibly organize the flow field based on actual combustion characteristics at a low cost, achieving safe, stable, and low-emission hydrogen fuel cell gas turbine combustion.

[0015] As can be seen from the above technical solution, the premixing nozzle and combustion chamber for hydrogen fuel gas turbine of the present invention have the following beneficial effects: (1) Compared with the traditional direct injection premixed nozzle, the premixed nozzle of the present invention has an annular gas film development channel. The fuel-air rapid mixing conduit in the middle of the gas film development channel makes the fuel / air mixed evenly. The annular air film can cool the nozzle wall and suppress boundary layer backfire, control the flame rise height and thermoacoustic dynamic response characteristics, thereby improving the safety and durability of the nozzle. (2) Compared with traditional premixed nozzles, the premixed nozzle of the present invention adopts a detachable lip, which can flexibly adjust the thickness of the nozzle lip, thereby achieving the purpose of adjusting the size of the local reaction zone near the lip according to the characteristics of the combustion chamber, and thus playing the role of adjusting the rise height of the reaction zone and suppressing thermoacoustic oscillation. (3) The combustion chamber is composed of the nozzles, which can reasonably organize the flow field of the combustion chamber according to the fuel characteristics; at the same time, it can flexibly adjust the lip thickness of each nozzle according to the actual combustion characteristics of the combustion chamber, and can reasonably organize the rise height and distribution of the reaction zone, suppress thermoacoustic oscillation, reduce nitrogen oxide emissions, thereby achieving safe and stable combustion of hydrogen fuel. Attached Figure Description

[0016] Figure 1 A cross-sectional view of a premixed nozzle according to an embodiment of the present invention; Figure 2 for Figure 1 The diagram shows the structure of the premixed nozzle. Figure 3 This is a schematic diagram of a premixed nozzle applied to the head of a gas turbine combustor according to an embodiment of the present invention.

[0017] Wherein, 1-film vapor deposition channel; 2-fuel-air rapid mixing duct; 3-shoulder ring with inverted conical hole; 4-conical nozzle lip edge; 5-combustion chamber nozzle; 6-removable nozzle lip edge; 7-fuel passage; D1-inner diameter of combustion chamber nozzle outlet; L1-distance between the center of fuel passage and the end face of combustion chamber nozzle outlet; L2-distance between the outlet end face of fuel-air rapid mixing duct and the outlet end face of combustion chamber nozzle; L3-radial distance between the outlet inner diameter of film vapor deposition channel and the outer diameter of fuel-air rapid mixing duct; L4-thickness of removable nozzle lip edge; θ1-angle between the outer wall of conical nozzle lip edge and the line connecting the axis; θ2-angle between the outer wall of removable shoulder ring with inverted conical hole and the line connecting the axis. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0019] like Figures 1-2 As shown, an embodiment of the present invention provides a premixed nozzle for a combustion chamber of a hydrogen fuel gas turbine, comprising: a gas film development channel 1, a fuel-air rapid mixing conduit 2, and a detachable nozzle lip edge 6.

[0020] The fuel-air rapid mixing conduit 2 is located at the center of the film gas development channel 1, and rapidly develops an annular film gas by utilizing the gap between the two to prevent backfire, thereby improving the safety of the combustion chamber nozzle 5. The conical nozzle lip edge 4 is externally fitted with a detachable collar 3 with an inverted conical hole; the two together form a detachable nozzle lip edge 6, which can be used to flexibly adjust the size of the local reaction zone according to the flow field organization requirements, thereby controlling the rise height of the reaction zone and suppressing thermoacoustic oscillations.

[0021] In this system, air enters from the bottom of the film gas development channel 1 and splits into two streams. One stream enters the fuel-air rapid mixing duct 2, where it is rapidly mixed with the fuel entering the combustion chamber nozzle 5 through the fuel channel 7. To ensure uniform circumferential distribution of fuel within the fuel-air rapid mixing duct 2, each combustion chamber nozzle 5 has P fuel channels 7, all of which connect to the fuel-air rapid mixing duct 2 and the film gas development channel 1. The number of fuel channels 7, P, should satisfy P ≥ 3. To ensure efficient fuel-air mixing, the distance L1 between the center of the fuel channel 7 and the outlet end face of the combustion chamber nozzle 5 satisfies: 5D1 ≤ L1 ≤ 20D1, where D1 is the inner diameter of the combustion chamber nozzle 5 outlet.

[0022] To avoid flow separation and reduce pressure loss, the radial distance L3 between the outlet inner diameter of the film gas development channel 1 and the outer diameter of the fuel-air rapid mixing duct 2 satisfies: 0.5 mm ≤ L3 ≤ 3 mm or L3 = 0 mm. When the film gas is not needed, the lifting height of the reaction zone can be finely adjusted simply by relying on the detachable nozzle lip edge 6, i.e., by replacing the detachable collar 3 with an inverted conical hole of different thickness. In this case, L3 = 0 mm, and the film gas development channel 1 coincides with the fuel-air rapid mixing duct 2. To further improve the mixing efficiency in the combustion chamber nozzle 5, the distance L2 between the outlet end face of the fuel-air rapid mixing duct 2 and the outlet end face of the combustion chamber nozzle 5 satisfies: 0 ≤ L2 ≤ 4D1.

[0023] To achieve adjustable lip thickness, the angle between the outer wall of the conical spray lip lip 4 and the line connecting it to the axis is θ1, satisfying... The detachable collar 3 with an inverted conical hole has an angle θ2 between its outer side wall and the line connecting it to the axis, satisfying θ2 = θ1. The thickness L4 of the detachable spray lip edge 6 satisfies: 0 mm ≤ L4 ≤ 5 mm.

[0024] like Figure 3 As shown, this embodiment of the invention provides a combustor for a hydrogen fuel cell gas turbine, including a plurality of premixed nozzles. To achieve safe, stable, and low-emission combustion in the hydrogen fuel cell gas turbine combustor, the premixed nozzles need to be evenly distributed in an organized manner, while also being able to be flexibly adjusted according to the needs of the flow field organization.

[0025] In this embodiment, the premixed nozzle outlet velocity is set to 20 m / s. 160 m / s. Under rated load conditions, through the effective organization of the premixed nozzle, the reaction zone can be stably anchored in the combustion chamber under the combustion conditions of hydrogen-containing fuels, especially high-hydrogen-content fuels or even pure hydrogen fuels, and at a certain distance from the combustion chamber nozzle, thereby improving the nozzle's safety and durability. Effective adjustment of the flow delay time enhances the combustion chamber's resistance to upstream disturbances, thus suppressing the occurrence and potential occurrence of thermoacoustic oscillations. Simultaneously, the rapid and uniform mixing of fuel and air reduces the formation of local hot spots caused by uneven mixing, lowering NO levels. x emission.

[0026] It should be noted that experimental methods not illustrated or described in the accompanying drawings or the main text of the specification are all forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various components above are not limited to the specific structures and shapes mentioned in the embodiments; those skilled in the art can easily modify or substitute them, for example: (1) The detachable collar with the inverted conical hole can also take other forms or structures, such as the collar can also be inverted conical in shape, as long as it can perform the same function; (2) The fuel passage connecting the fuel-air rapid mixing duct and the gas film development channel inside a single combustion chamber nozzle can also be tilted at an appropriate angle, as long as the fuel-air mixing degree at the nozzle outlet meets the requirements. (3) The present invention may provide examples of parameters containing specific values, but these parameters need not be exactly equal to the corresponding values, but can be approximated within acceptable error tolerances or design constraints; (4) The directional terms mentioned in the implementation, such as “front” and “back”, are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of the present invention.

[0027] In summary, the premixed nozzle provided by this invention fully utilizes the gas film structure and the adjustability of the lip thickness, improving the nozzle's safety and durability. The presence of the annular gas film reduces the temperature of the nozzle lip wall, delaying the formation of the flame front during the combustion of hydrogen-containing fuels, especially high-hydrogen-content fuels or even pure hydrogen fuels, thus preventing backfire. The detachable nozzle lip, by achieving adjustable lip thickness, alters the combustion chamber reaction zone lifting characteristics, thereby improving nozzle safety and durability. Furthermore, the change in flow delay time enhances the combustion chamber's resistance to upstream disturbances, suppressing the occurrence and potential occurrence of thermoacoustic oscillations. Simultaneously, the combustion chamber, composed of several nozzles, can organize the combustion chamber flow field according to fuel characteristics and, more importantly, flexibly organize the flow field based on actual combustion characteristics at a low cost, thereby achieving safe, stable, and low-emission hydrogen fuel cell gas turbine combustion.

[0028] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. The above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combustion chamber premix nozzle for a hydrogen fuel gas turbine, characterized by, include: The system comprises a film gas development channel, a fuel-air rapid mixing duct, and a detachable nozzle lip edge. The fuel-air rapid mixing duct is located at the center of the film gas development channel. Air enters from the bottom of the channel and splits into two streams. One stream enters the fuel-air rapid mixing duct and is then rapidly mixed with fuel entering the combustion chamber nozzle from the fuel channel. The other stream flows along the film gas development channel to the nozzle outlet and forms an annular film gas near the nozzle outlet using the gap between the film gas development channel and the fuel-air rapid mixing duct to prevent backfire. The detachable nozzle lip edge is located on one side of the fuel-air rapid mixing duct and is formed by a detachable collar with an inverted conical hole and a conical nozzle lip edge fixed to the nozzle. It is used to flexibly adjust the size of the local reaction zone according to the flow field organization requirements, thereby controlling the rise height of the reaction zone and suppressing thermoacoustic oscillations. The radial distance L3 between the outlet inner diameter of the gas film development channel and the outer diameter of the fuel-air rapid mixing duct satisfies the following: when an annular gas film is required, 0.5 mm ≤ L3 ≤ 3 mm; when an annular gas film is not required, the lifting height of the reaction zone is finely adjusted by replacing the detachable nozzle edge of different thicknesses, and L3 = 0 mm.

2. A combustion chamber premix nozzle for a hydrogen fuel gas turbine according to claim 1, characterized by Each combustion chamber nozzle has P fuel channels, which are connected to a fuel-air rapid mixing duct and a film gas development channel.

3. A combustion chamber premix nozzle for a hydrogen fuel gas turbine according to claim 2, characterized by The number of fuel channels P satisfies P ≥ 3.

4. A premixing nozzle for a combustion chamber of a hydrogen fuel cell gas turbine according to claim 1, characterized in that, The distance L1 between the center of the fuel passage and the outlet end face of the combustion chamber nozzle satisfies: 5D1 ≤ L1 ≤ 20D1, where D1 is the inner diameter of the combustion chamber nozzle outlet.

5. A premixing nozzle for a combustion chamber of a hydrogen fuel cell gas turbine according to claim 1, characterized in that, The distance L2 between the outlet end face of the fuel-air rapid mixing duct and the outlet end face of the combustion chamber nozzle satisfies: 0 ≤ L2 ≤ 4D1.

6. A premixing nozzle for a combustion chamber of a hydrogen fuel cell gas turbine according to claim 1, characterized in that, The angle between the outer wall of the conical spray nozzle lip and the line connecting the axis is θ1, which satisfies 0° ≤ θ1 ≤ 25˚.

7. A premixing nozzle for a combustion chamber of a hydrogen fuel cell gas turbine according to claim 6, characterized in that, The detachable collar with an inverted conical hole causes the angle between the outer side wall and the line connecting the axis to be θ2, which satisfies θ2 = θ1.

8. A premixing nozzle for a combustion chamber of a hydrogen fuel cell gas turbine according to claim 1, characterized in that, The thickness of the detachable spray lip edge is L4, satisfying: 0 mm ≤ L4 ≤ 5 mm.

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