Micro-sized fuel air jet mixing nozzle

Abstract

This application belongs to the field of combustion chamber design, and specifically relates to a micro-sized fuel-air jet mixing nozzle, including an air pipe, a fuel nozzle, and a combustion chamber flame tube; the air pipe and fuel nozzle are coaxially arranged, the air pipe is connected to the combustion chamber flame tube, the fuel nozzle is inserted into the air pipe, the fuel nozzle has a cylindrical structure, the outlet end of the fuel nozzle has a coaxial nozzle hole, and the side wall has an inclined nozzle hole, the outlet of the inclined nozzle hole facing the combustion chamber flame tube. The swirler is eliminated, thus eliminating the large-scale low-speed backflow zone; the use of an 8–15 mm micro-sized air pipe significantly improves the wall heat dissipation capacity, reducing the boundary layer temperature and the probability of spontaneous combustion; the inclined jet is injected along the mainstream direction, avoiding reverse flow, suppressing high-hydrogen fuel backfire at the source, and significantly improving the operational safety of the combustion chamber; the coaxial jet and the inclined jet work together to achieve rapid and uniform premixing of fuel and air over a short distance, avoiding localized rich-fuel high-temperature zones.

Description

Technical Field

[0001] This application belongs to the field of combustion chamber design, and specifically relates to a micro-sized fuel-air jet mixing nozzle. Background Technology

[0002] Against the backdrop of "dual carbon" (carbon, oxygen, and carbon emissions), gas turbines urgently need to reduce carbon emissions during their application. One of the most effective measures currently is to replace the fossil fuels commonly used in gas turbines, such as natural gas, with low-carbon or zero-carbon fuels. In IGCC power plants, gas turbines can significantly reduce carbon emissions by burning syngas, contributing to the achievement of dual carbon goals. Compared to natural gas, syngas contains a higher volume fraction of H2, making it more prone to backfire during combustion in the combustion chamber, and resulting in higher NOx emissions.

[0003] Currently, there are two common combustion methods used in combustion chambers that burn syngas: one is diffusion combustion, which uses N2, water vapor, or CO2 for dilution to reduce emissions; the other is large-scale premixed combustion.

[0004] The main drawbacks of existing technical solutions are:

[0005] 1. High risk of backfire: Existing large-size premixed combustion chambers use cyclones to generate a backflow zone to stabilize the flame, which creates a large low-speed zone. Therefore, when using syngas, backfire is likely to occur.

[0006] 2. High NOx emissions: Existing large-size premixed combustion chambers use cyclones to create a recirculation zone to stabilize the flame. The high-temperature flame area is large, so when using syngas, NOx emissions are high.

[0007] 3. Poor fuel flexibility: Existing large-size premixed combustors are prone to backfire when using syngas. This limits the H2 content in the syngas. In practical applications, the restrictions on fuel composition are even more stringent, limiting the application of gas turbines.

[0008] Therefore, how to design a more effective combustion chamber nozzle structure is a problem that needs to be solved. Summary of the Invention

[0009] To address the aforementioned issues, this application provides a micro-sized fuel-air jet mixing nozzle to solve the problems of high backfire risk, high NOx emissions, and poor fuel flexibility in existing combustion chamber nozzle structures.

[0010] The technical solution of this application is: a micro-sized fuel-air jet mixing nozzle, comprising an air pipe, a fuel nozzle, and a combustion chamber flame tube;

[0011] The air pipe and the fuel nozzle are coaxially arranged. The air pipe is connected to the combustion chamber flame tube. The fuel nozzle is inserted into the air pipe. The fuel nozzle has a cylindrical structure. The outlet end of the fuel nozzle has a coaxial nozzle hole, and the side wall has an inclined nozzle hole. The outlet of the inclined nozzle faces the combustion chamber flame tube.

[0012] Preferably, there are multiple inclined nozzles arranged in a ring at intervals around the axis of the fuel nozzle.

[0013] Preferably, there is a gap between the fuel nozzle and the air pipe to form an annular air passage.

[0014] Preferably, the inner diameter of the air tube is between 8 and 15 mm.

[0015] Preferably, the tilt angle between the axis of the inclined nozzle and the axis of the fuel nozzle is between 20° and 75°.

[0016] Preferably, the air pipe includes an inlet section, a convex section, and a constriction section; the inlet section, the convex section, and the constriction section are integrally formed, the convex section corresponds to the outlet position value of the inclined nozzle, and the constriction section constricts inward in an arc after the convex section.

[0017] The micro-sized fuel-air jet mixing nozzle of this application has the following advantages:

[0018] 1. Significantly reduces the risk of backfire

[0019] The cyclone separator is eliminated, thus removing the large-scale low-speed backflow zone; 8–15 mm micro-sized air pipes are used to significantly improve the wall heat dissipation capacity, reduce the boundary layer temperature and the probability of spontaneous combustion; the inclined jet is sprayed along the mainstream direction to avoid reverse flow, thereby suppressing backfire of high-hydrogen fuel from the source and significantly improving the operational safety of the combustion chamber.

[0020] 2. Significantly reduce NO x emission

[0021] The combination of coaxial and inclined jets enables rapid and uniform premixing of fuel and air over a short distance, avoiding localized high-temperature, oil-rich zones; the micro-structure reduces flame volume and temperature, effectively suppressing thermal NOx. x It generates emissions that meet the low-emission environmental protection requirements of gas turbines.

[0022] 3. Significantly improves fuel adaptability

[0023] With improved backfire resistance, it can stably burn syngas and hydrogen-rich fuels with large fluctuations in hydrogen content, breaking through the strict limitations of traditional premixed combustion chambers on fuel composition. It is suitable for fuel supply in multiple scenarios such as IGCC power plants and low-carbon gas turbines, greatly expanding its application scope. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of this application.

[0025] 1. Air pipe; 2. Fuel nozzle; 3. Coaxial nozzle; 4. Inclined nozzle; 5. Fuel; 6. Air; 7. Combustion chamber flame tube; 8. Inlet section; 9. Outward protrusion section; 10. Contraction section. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0027] The first aspect of this application provides a micro-sized fuel-air jet mixing nozzle, such as Figure 1 As shown, it includes an air pipe 1, a fuel nozzle 2, and a combustion chamber flame tube 7;

[0028] Air pipe 1 and fuel nozzle 2 are coaxially arranged. Air pipe 1 is connected to combustion chamber flame tube 7. Fuel nozzle 2 is inserted into air pipe 1. Fuel 5 nozzle has a cylindrical structure. The outlet end of fuel nozzle 2 is provided with coaxial nozzle 3 and inclined nozzle 4 is provided on the side wall. The outlet of inclined nozzle 4 faces combustion chamber flame tube 7.

[0029] By setting the air pipe 1 and fuel nozzle 2 coaxially, a symmetrical and stable jet flow field is formed, avoiding deflection and backflow. The fuel nozzle 2 adopts a combination of coaxial nozzle 3 and inclined nozzle 4 to achieve synchronous radial and axial diffusion of fuel 5, improving the mixing uniformity. The inclined nozzle 4 is directed towards the combustion chamber flame tube 7, so that fuel 5 is directly injected along the airflow direction, reducing reverse flow and pipe wall adhesion, structurally eliminating the risk of backfire, and ensuring that fuel 5 and air 6 are quickly mixed and directly enter the combustion zone, improving combustion efficiency and stability.

[0030] Preferably, there are multiple inclined nozzles 4 arranged in a ring around the axis of the fuel nozzle 2. The circumferentially spaced inclined nozzles 4 can form a uniform fuel jet field, avoiding excessively high or low local fuel concentrations and achieving uniform mixing across the entire cross-section.

[0031] Preferably, there is a gap between the fuel nozzle 2 and the air pipe 1, forming an annular air channel 6. The annular air channel 6 formed between the fuel nozzle 2 and the air pipe 1 ensures that the air 6 flows uniformly along the pipe wall, forming an air 6 protective film, reducing the risk of fuel 5 directly scouring the pipe wall, and suppressing backfire of the pipe wall boundary layer.

[0032] Preferably, the inner diameter of the air pipe 1 is between 8 and 15 mm, which rapidly reduces the temperature of the gas mixture inside the pipe and suppresses spontaneous combustion and backfire.

[0033] Preferably, the tilt angle between the axis of the inclined nozzle 4 and the axis of the fuel nozzle 2 is between 20° and 75°. This ensures the forward movement of the jet while creating a moderate vortex disturbance, enhancing the turbulent mixing of fuel 5 and air 6.

[0034] Preferably, the air pipe 1 includes an inlet section 8, a convex section 9, and a constriction section 10; the inlet section 8, the convex section 9, and the constriction section 10 are integrally formed, the convex section 9 corresponds to the outlet position of the inclined nozzle 4, and the constriction section 10 constricts inward in an arc after the convex section 9. The convex section 9 provides sufficient spray space for the inclined nozzle 4, avoiding jet impact on the pipe wall; the constriction section 10 gathers the airflow, increases the outlet velocity, enhances the jet rigidity, and suppresses backfire.

[0035] In summary, this application has the following advantages:

[0036] 1. Significantly reduces the risk of backfire

[0037] The cyclone separator is eliminated, thus removing the large-scale low-speed backflow zone; 8–15 mm micro-sized air pipes are used to significantly improve the wall heat dissipation capacity, reduce the boundary layer temperature and the probability of spontaneous combustion; the inclined jet is sprayed along the mainstream direction to avoid reverse flow, thereby suppressing backfire of high-hydrogen fuel from the source and significantly improving the operational safety of the combustion chamber.

[0038] 2. Significantly reduce NO x emission

[0039] The combination of coaxial and inclined jets enables rapid and uniform premixing of fuel and air over a short distance, avoiding localized high-temperature, oil-rich zones; the micro-structure reduces flame volume and temperature, effectively suppressing thermal NOx. x It generates emissions that meet the low-emission environmental protection requirements of gas turbines.

[0040] 3. Significantly improves fuel adaptability

[0041] With improved backfire resistance, it can stably burn syngas and hydrogen-rich fuels with large fluctuations in hydrogen content, breaking through the strict limitations of traditional premixed combustion chambers on fuel composition. It is suitable for fuel supply in multiple scenarios such as IGCC power plants and low-carbon gas turbines, greatly expanding its application scope.

[0042] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A micro-sized fuel-air jet mixing nozzle, characterized in that, It includes an air pipe (1), a fuel nozzle (2), and a combustion chamber flame tube (7); The air pipe (1) and the fuel nozzle (2) are coaxially arranged. The air pipe (1) is connected to the combustion chamber flame tube (7). The fuel nozzle (2) is inserted into the air pipe (1). The fuel (5) nozzle has a cylindrical structure. The outlet end of the fuel nozzle (2) is provided with a coaxial nozzle hole (3) and the side wall is provided with an inclined nozzle hole (4). The outlet of the inclined nozzle hole (4) faces the combustion chamber flame tube (7).

2. The micro-sized fuel-air jet mixing nozzle as described in claim 1, characterized in that, The inclined nozzles (4) are multiple and are arranged in a ring-shaped interval around the axis of the fuel nozzle (2).

3. The micro-sized fuel-air jet mixing nozzle as described in claim 1, characterized in that, There is a gap between the fuel nozzle (2) and the air pipe (1) to form an annular air (6) channel.

4. The micro-sized fuel-air jet mixing nozzle as described in claim 1, characterized in that, The inner diameter of the air tube (1) is between 8 and 15 mm.

5. The micro-sized fuel-air jet mixing nozzle as described in claim 1, characterized in that, The tilt angle between the axis of the inclined nozzle (4) and the axis of the fuel nozzle (2) is between 20° and 75°.

6. The micro-sized fuel-air jet mixing nozzle as described in claim 1, characterized in that, The air pipe (1) includes an inlet section (8), a convex section (9), and a constriction section (10); the inlet section (8), the convex section (9), and the constriction section (10) are integrally formed, the convex section (9) corresponds to the outlet position value of the inclined nozzle (4), and the constriction section (10) is arc-shaped and constricted inward after the convex section (9).

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