Double-zone combustor and combustion method thereof

Abstract

The invention discloses a double-zone combustor and a combustion method thereof, and belongs to the technical field of combustor equipment.The double-zone combustor comprises a combustion chamber casing, a first fuel inlet and a first blade swirler are arranged on one side of the interior of the combustion chamber casing, and a second fuel inlet and a second blade swirler are arranged at the position, close to the middle, of the interior of the combustion chamber casing; the area between the first blade swirler and the second blade swirler is a pre-combustion area, the area on the side, away from the pre-combustion area, of the second blade swirler is a main combustion area, the main combustion area is communicated with the pre-combustion area, and a fuel outlet is formed in the side, away from the first fuel inlet, of the interior of the combustion chamber case. Through the double-area configuration of the pre-combustion area and the main combustion area, stable ignition and flame stability are ensured through methane, which is crucial for starting combustion, the hydrogen supply main area can reduce the oil-gas ratio to the greatest extent, the efficiency is improved, the emission of nitrogen oxides and carbon dioxide is remarkably reduced, and the special area separation is realized, so that the energy consumption is reduced. Independent control of fuel types is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of burner equipment, and in particular to a dual-zone burner and a combustion method thereof. Background Art

[0002] With the increasing emphasis on environmental protection and the proposal of dual carbon goals, gas turbine engines, industrial burners, etc. need to reduce pollutant emissions as much as possible to meet various environmental protection policies issued by the country. 4 ) and hydrogen (H 2 ) in a hybrid burner has been extensively studied as they each have advantages in terms of stable ignition and improved combustion efficiency. Methane is a stable fuel with low reactivity and is ideal as a pre-combustion zone, ensuring continued ignition stability under varying operating conditions. Hydrogen, on the other hand, excels in reducing pollutant emissions and improving overall combustion efficiency in the main combustion zone due to its higher energy density and faster flame propagation characteristics.

[0003] In view of the above-mentioned related technologies, the applicant has found that the current burners are incapable of managing CH 4 and H 2 There are technical difficulties in the transition between combustion zones. Problems such as flashback, flame instability and uneven combustion during the transition will lead to higher emissions and pollute the environment, thereby reducing the reliability of combustion and increasing safety risks. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a dual-zone burner and a combustion method thereof, which solves the problems of flashback, flame instability and uneven combustion during transition, reduces pollutants emitted by combustion, protects the environment, and further improves combustion reliability and reduces safety risks.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A dual-zone burner comprises a combustion chamber casing, wherein a fuel inlet 1 and a blade swirler 1 are provided on one side inside the combustion chamber casing, a fuel inlet 2 and a blade swirler 2 are provided near the middle of the combustion chamber casing, an area between the blade swirler 1 and the blade swirler 2 is a pre-combustion zone, an area on the side of the blade swirler 2 away from the pre-combustion zone is a main combustion zone, the main combustion zone and the pre-combustion zone are connected to each other, and a fuel outlet is provided on the side inside the combustion chamber casing away from the fuel inlet 1.

[0007] Furthermore, the blade swirler 1 and the blade swirler 2 both include rotating blades and partition plates.

[0008] Furthermore, a bushing is provided inside the combustion chamber casing, the bushing is placed between the main combustion zone and the casing of the combustion chamber casing, and the bushing is provided with radial holes.

[0009] Furthermore, the bushing is made of high temperature resistant material.

[0010] A combustion method of a dual-zone burner comprises the following steps:

[0011] Step 1: methane fuel is injected into the pre-combustion zone (3) through the fuel inlet 1 (1) and mixed with the swirling air introduced by the blade swirler 1 (2);

[0012] Step 2: Combustion begins in the pre-combustion zone (3). Turbulence increases the residence time r of the fuel-air mixture, which is calculated as follows:

[0013] r=L / v

[0014] Where L is the characteristic length, v is the average velocity, and extending the residence time r can ensure adequate mixing and combustion of methane;

[0015] Exothermic reactions release heat Q:

[0016]

[0017] in is the mass flow rate of methane, ΔH comb is the calorific value of methane;

[0018] Step 3: Hydrogen fuel is introduced at the end of the blade swirler 2 (5), quickly mixed with the air in the main combustion zone (6), and ignited by the high-temperature combustion gas in the pre-combustion zone (3);

[0019] Step 4: The velocity path line caused by the vortex follows a spiral trajectory to form an inner recirculation zone IRZ and an outer recirculation zone ORZ, and the hot gas in the recirculation zone maintains combustion;

[0020] Step 5: The radial holes (7) introduce secondary air, which has a dual function of cooling the inner wall and diluting the combustion gas to adjust the outlet temperature field;

[0021] Step 6: The fuel outlet (8) effectively delivers the combustion products and ensures a relatively uniform velocity and temperature distribution at the outlet to reduce pressure loss and high temperature erosion of downstream turbine components.

[0022] Further, in step 1, the blade swirler 1 imparts a rotational motion, generating a strong centrifugal force, as described below:

[0023]

[0024] Where ρ is the air density, v θis the tangential velocity, and r is the radius of the swirl. This centrifugal force forms a central recirculation zone (CRZ) that stabilizes the flame by recirculating hot combustion products, and the separator ensures symmetry and prevents undesirable flow interactions between the swirls;

[0025] The methane oxidation reaction rate r is governed by the Arrhenius equation:

[0026]

[0027] Where A is the pre-exponential factor, E a is the activation energy, R is the universal gas constant, T is the temperature, and are the concentrations of methane and oxygen, respectively.

[0028] Furthermore, in step 3, due to its lower molecular weight and higher diffusion rate, hydrogen mixes faster than methane. Its low ignition delay and wide flammability range make it an ideal choice for lean burn combustion. The flame propagation speed SL is given by the following formula:

[0029] S L =αT β P α f(T, P)

[0030] Where T and P are the local temperature and pressure, α and β depend on the fuel type, and f(T,P) is a function that captures the nonlinear effects of temperature and pressure on flame speed. The main combustion zone is operated at a lean fuel-air ratio to suppress NOx emissions primarily through the Zeldovich mechanism:

[0031] O+N 2 →NO+N

[0032] N+O 2 →NO+O

[0033] N+OH→NO+H

[0034] The vane swirler two-stage design creates a secondary circulation zone that stabilizes the flame over a wide range of operating conditions.

[0035] Furthermore, in step 4, the turbulent kinetic energy K in the flow is expressed as:

[0036]

[0037] where u 2 、v 2 and w 2 These are the velocity fluctuations in the x, y and z directions, respectively. The strong shear layer at the interface between the inner recirculation zone IRZ and the outer recirculation zone ORZ enhances turbulent mixing.

[0038] Furthermore, in step 5, the convective heat transfer rate Q for cooling conv It is given by the following formula:

[0039] Q conv =hA(T 气体 +T 墙 )

[0040] Where h is the heat transfer coefficient, A is the surface area, T 气体 is the gas temperature, T 墙 The secondary air forms an air film to lower the wall temperature, protecting the inner wall from thermal stress and reducing the peak flame temperature, thereby minimizing the formation of NOx.

[0041] Furthermore, in step six, the total pressure loss ΔP of the combustion chamber is:

[0042]

[0043] Where f is the Darcy friction coefficient, which depends on the Reynolds number and the pipe roughness; L is the length of the pipe or conduit; D is the hydraulic diameter of the pipe or conduit; p is the fluid density; and v is the average flow velocity.

[0044] In summary, compared with the prior art, the above technical solution has the following beneficial effects:

[0045] (1) Through the dual-zone configuration of the pre-combustion zone and the main combustion zone, methane ensures stable ignition and flame stabilization, which is critical for starting combustion, while hydrogen supplies the main zone to minimize the oil-gas ratio, improve efficiency and significantly reduce nitrogen oxide and carbon dioxide emissions. Dedicated zone separation maintains independent control of fuel type;

[0046] (2) Through the advanced fuel injection setting, hydrogen fuel is injected through the dedicated inlet hole 2 located at the end of the vane swirler 2, which ensures the controllability of the mixture and prevents flashback, which is a key safety measure for hydrogen-rich combustion. The double tangential vane swirler uses co-rotating blades, which introduces a strong swirl motion, enhances turbulence, and ensures sufficient fuel-air mixing in the methane and hydrogen regions;

[0047] (3) Emission control: By optimizing the equivalent ratio of the main combustion zone, the system can minimize nitrogen oxide (NOx) formation and unburned hydrocarbons. This helps meet stringent regulatory standards while maintaining a stable flame and low pollutant emissions;

[0048] (4) Enhanced safety: flame arresters and sophisticated monitoring systems in both zones detect abnormal conditions and prevent backflow-related explosions. The arrangement of injection points and separation of zones further improve operational safety during the transient phase.

[0049] (5) Material adaptability. Given the high reactivity and diffusivity of hydrogen, key components of the burner, especially near the main combustion zone, are made of hydrogen-resistant materials to withstand high temperatures and corrosive conditions without affecting durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of the overall structure of the dual-zone burner in an embodiment of the present invention.

[0051] Explanation of the reference numerals: 1. fuel inlet 1; 2. blade swirler 1; 3. pre-combustion zone; 4. fuel inlet 2; 5. blade swirler 2; 6. main combustion zone; 7. radial hole; 8. fuel outlet. DETAILED DESCRIPTION

[0052] The principles and features of the present invention are described below in conjunction with all the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0053] The embodiment of the invention discloses a dual-zone burner and a combustion method thereof.

[0054] Reference Figure 1 , the current burner is managing CH 4 and H 2 There are technical difficulties in the transition between combustion zones. During the transition, due to problems such as flashback, flame instability and uneven combustion, higher emissions will be generated, polluting the environment, thereby reducing the reliability of combustion and increasing the potential safety risks. In addition, the high diffusivity and reactivity of hydrogen increase the possibility of flame extinction or flashback to the pre-combustion zone 3, and the incompatibility of materials with hydrogen thermal stress further exacerbates the durability problem. Existing burners also have difficulty in optimizing the equivalent ratio to achieve maximum efficiency without sacrificing NO x These deficiencies highlight the need for innovative solutions to improve the robustness, adaptability, and safety of hybrid burner designs.

[0055] Reference Figure 1 A dual-zone burner includes a combustion chamber casing, a fuel inlet 1 and a blade swirler 2 are provided on one side of the combustion chamber casing, a fuel inlet 4 and a blade swirler 5 are provided near the middle of the combustion chamber casing, and the blade swirler 2 and the blade swirler 5 both include rotating blades and partition plates.

[0056] The area between blade swirler 1 2 and blade swirler 2 5 is the pre-combustion zone 3, and the area on the side of blade swirler 2 5 away from the pre-combustion zone 3 is the main combustion zone 6. The main combustion zone 6 is interconnected with the pre-combustion zone 3, and the main combustion zone 6 is made of hydrogen-resistant material.

[0057] A fuel outlet 8 is provided inside the combustion chamber casing at a side away from the fuel inlet 1. A bushing is provided inside the combustion chamber casing, and the bushing is placed between the main combustion zone 6 and the casing (outer shell) of the combustion chamber casing, and the bushing is provided with radial holes 7. The bushing is made of high temperature resistant material.

[0058] The combustion process is optimized by using methane in the pre-combustion zone 3 and hydrogen in the main combustion zone 6. The design has different functional areas:

[0059] Pre-combustion zone 3 (CH 4 The combustion zone uses methane as the combustion agent, which has low reactivity and stability. 4 The fuel enters through the fuel inlet 1 into a chamber pre-combustion zone 3 with a flame stabilization structure, which ensures a stable ignition source and minimizes the risk of flame explosion.

[0060] Equivalence ratio: Keep slightly rich (Φ≈1.1) to achieve stable flame ignition.

[0061] Main combustion zone 6 (H 2 The main combustion zone (6) is equipped with a special cooling element and material reinforcement to handle the H2. 2 Heat stress from combustion.

[0062] Equivalence ratio: streamlined operation (Φ≈0.6) achieves efficient combustion while reducing NO x Emissions are reduced to a minimum.

[0063] The transition zone is the area between the pre-combustion zone 3 and the main combustion zone 6. 4 and H 2 The zones are separated and cross flame interference is prevented by using vane swirlers and flame stabilization components.

[0064] Flashback and explosion mitigation issues, using equipment such as flame retardants, controlled flow paths and real-time monitoring systems, can prevent upstream flame propagation and ensure safety under changing conditions.

[0065] Material innovation is to make burner components out of hydrogen-resistant alloys to reduce thermal stress and embrittlement.

[0066] Methane fuel is injected into the pre-combustion zone 3 through the fuel inlet 1, and then passes through the double tangential blade swirler 2. The blades rotate together to introduce swirl motion to ensure effective mixing of fuel and air. The partition plate separates the blade swirler 2 to improve stability. The pre-combustion zone 3 promotes the initial combustion process and stabilizes the flame. The hydrogen fuel enters through the fuel inlet 24 placed in the tube at the end of the blade swirler 25. The main combustion zone 6 is similar to the pre-combustion zone 3. The main combustion zone 6 also uses a double tangential blade swirler 25 with co-rotating blades and partition plates to achieve optimal fuel-air mixing. The main combustion zone 6 supports the main combustion stage and maintains efficient combustion under different operating conditions. Another set of radial holes 7 in the liner further optimizes air distribution to enhance cooling and emission reduction. The fuel outlet 8 guides the combustion products out of the system.

[0067] This dual-zone burner design addresses the limitations of conventional single-fuel burners by using separate methane and hydrogen combustion zones. The pre-combustion zone 3 ensures reliable ignition of methane due to its lower flashback sensitivity, while the main combustion zone 6 utilizes hydrogen for its superior combustion efficiency and low carbon emissions. The fuel inlet 24 of the hydrogen injection system is precisely positioned and diameter optimized to enhance air-fuel interaction and promote uniform mixing. This results in a more stable flame, reduced risk of hot spots, and lower NO x emission.

[0068] Additionally, vane swirlers 1 2 and 2 5, combined with strategically placed radial holes 7, ensure uniform temperature distribution and improved flame cooling. This configuration reduces thermal stress on the liner, extends component life, and enables efficient operation of high-efficiency gas turbine systems. The combustor’s robust design, with independent air and fuel controls for each zone, allows for precise adjustment of fuel ratios, making it ideal for industrial applications requiring low-emission, high-efficiency performance. The innovative feature hydrogen injection system, especially the enhanced vane swirler and fuel inlet configuration, makes the design highly resistant to flashback while optimizing combustion dynamics. These improvements support modern power generation needs, ensuring lower greenhouse gas emissions and safer operations.

[0069] Through the dual-zone configuration of pre-combustion zone 3 and main combustion zone 6, methane ensures stable ignition and flame stabilization, which is crucial for starting combustion, while hydrogen supplies the main zone to minimize the oil-gas ratio, improve efficiency and significantly reduce nitrogen oxide and carbon dioxide emissions. Dedicated zone separation maintains independent control of fuel type.

[0070] Through the advanced fuel injection setting, hydrogen fuel is injected through a dedicated air inlet port 2 located at the end of the vane swirler 25, which ensures the controllability of the mixture and prevents backfire, which is a key safety measure for hydrogen-rich combustion. The double tangential vane swirler uses co-rotating blades to introduce a strong swirl motion, enhance turbulence, and ensure sufficient fuel-air mixing in the methane and hydrogen regions.

[0071] Emission control, by optimizing the equivalence ratio of the main combustion zone, the system can minimize nitrogen oxide (NOx) formation and unburned hydrocarbons. This helps meet strict regulatory standards while maintaining a stable flame and low pollutant emissions.

[0072] Safety is enhanced, flame arresters in both zones and a sophisticated monitoring system detect abnormal conditions and prevent backflow-related explosions, the arrangement of injection points and the separation of zones further improve operational safety during the transient phase.

[0073] Material adaptability. In view of the high reactivity and diffusivity of hydrogen, the key components of the burner, especially near the main combustion zone 6, are made of hydrogen-resistant materials to withstand high temperature and corrosive conditions without affecting durability.

[0074] Reference Figure 1 , dual-zone gas turbine combustors achieve efficient fuel-air mixing, flame stabilization, and emissions control through a series of complex aerodynamic and combustion phenomena. Below is a detailed explanation of the physical processes, related equations, and the physical properties of methane and hydrogen.

[0075] Reference Figure 1 , a dual-zone burner and a combustion method thereof, comprising the following steps:

[0076] Step 1: Fuel injection and swirl generation (pre-combustion zone 3)

[0077] Methane fuel is injected into the pre-combustion zone 3 through the fuel inlet 1 and mixed with the swirling air introduced by the blade swirler 2;

[0078] The blade cyclone 2 imparts a rotating motion, generating a strong centrifugal force, as described below:

[0079]

[0080] Where ρ is the air density, v θ is the tangential velocity and r is the radius of the swirl. This centrifugal force creates a central recirculation zone (CRZ) that stabilizes the flame by recirculating the hot combustion products. The separator plate ensures symmetry and prevents undesirable flow interactions between the swirls.

[0081] The methane oxidation reaction rate r is governed by the Arrhenius equation:

[0082]

[0083] where A is the pre-exponential factor, Ea is the activation energy, R is the universal gas constant, T is the temperature, and are the concentrations of methane and oxygen, respectively.

[0084] Step 2: Combustion in pre-combustion zone 3

[0085] Combustion begins in the pre-combustion zone 3 because turbulence increases the residence time r of the fuel-air mixture, which is calculated as follows:

[0086] r=L / v

[0087] Where L is the characteristic length, v is the average flow velocity, and extending the residence time r can ensure sufficient mixing and combustion of methane.

[0088] Exothermic reactions release heat Q:

[0089]

[0090] in is the mass flow rate of methane, ΔH comb is the heating value of methane. The swirling air enhances turbulence, breaking the fuel into smaller droplets for efficient combustion.

[0091] Step 3: Hydrogen injection and combustion in the main combustion zone 6

[0092] Hydrogen fuel is introduced at the end of the blade swirler 5, quickly mixes with the air in the main combustion zone 6, and is ignited by the high temperature combustion gas in the pre-combustion zone 3. Due to its lower molecular weight and higher diffusion rate, hydrogen mixes faster than methane, reducing the possibility of flameout. Its low ignition delay and wide flammability range make it ideal for lean burn combustion. Flame propagation speed S L It is given by the following formula:

[0093] S L =αT β P α f(T, P)

[0094] Where T and P are the local temperature and pressure, α and β depend on the fuel type, and f(T,P) is a function that captures the nonlinear effects of temperature and pressure on flame speed. The main combustion zone 6 is operated at a lean fuel-air ratio to suppress NOx emissions mainly through the Zeldovich mechanism:

[0095] O+N 2 →NO+N

[0096] N+O 2 →NO+O

[0097] N+OH→NO+H

[0098] The vane swirler II 5 design produces a secondary recirculation zone (SRZ) that stabilizes the flame over a wide range of operating conditions.

[0099] Step 4: Flow Path Lines and Combustion Dynamics

[0100] The velocity path line caused by the vortex follows a spiral trajectory, forming an inner recirculation zone IRZ and an outer recirculation zone ORZ, which maintain combustion through the hot gas in the recirculation zone. These zones act as flame holders, maintaining combustion by recirculating hot gases. The turbulent kinetic energy K in the flow is expressed as:

[0101]

[0102] where u 2 、v 2 and w 2 are velocity fluctuations in the x, y, and z directions, respectively. The intense shear layer at the interface of the inner recirculation zone (IRZ) and the outer recirculation zone (ORZ) enhances turbulent mixing. Flow reversals near the liner wall caused by opposite pressure gradients help prevent flashbacks but require precise design to avoid instabilities.

[0103] Step 5: Secondary air distribution and cooling

[0104] The radial holes 7 introduce secondary air, which has a dual role: cooling the inner wall and diluting the combustion gas to adjust the outlet temperature field. Convective heat transfer rate for cooling Q conv It is given by the following formula:

[0105] Q conv =hA(T 气体 +T 墙 )

[0106] Where h is the heat transfer coefficient, A is the surface area, T 气体 is the gas temperature, T 墙 The secondary air forms a gas film that protects the inner wall from thermal stress and reduces the peak flame temperature, thereby minimizing the formation of NOx.

[0107] Step 6: Exhaust and Emission Control

[0108] The gas outlet 8 effectively delivers the combustion products and ensures a relatively uniform velocity and temperature distribution at the outlet to reduce pressure loss and high temperature erosion of downstream turbine and other components. The total pressure loss ΔP of the combustion chamber is:

[0109]

[0110] Where f is the Darcy friction coefficient, which depends on the Reynolds number and the pipe roughness; L is the length of the pipe or conduit; D is the hydraulic diameter of the pipe or conduit; p is the fluid density; and v is the average flow velocity.

[0111] Proper air distribution and flow management ensure low emissions of unburned hydrocarbons (UHC), carbon monoxide (CO) and nitrogen oxides (NOx) in compliance with environmental regulations.

[0112] The dual-zone burner design balances efficient energy release and flame stabilization. Swirls, recirculation zones, and turbulent flow dynamics enhance fuel-air mixing and flame stabilization. Judicious use of hydrogen injection improves lean burn stability, while multi-stage cooling mitigates thermal stress. Understanding the flow path, chemical kinetics, and turbulent behavior is critical to further optimize burner performance and achieve low emissions.

[0113] Since nitrogen oxides are the most concerned harmful gases that pollute the environment at present, and the main mechanism of nitrogen oxide production is the oxidation of nitrogen in the air at high temperature (temperature above 1800K), the most important means of controlling nitrogen is to control the temperature of the combustion zone not to be too high, and the temperature of the combustion zone below 1800K requires the oil-gas ratio to be kept at a low level, but a low oil-gas ratio can easily cause flameout. The outstanding feature of this method is that the pre-combustion zone 3 always keeps burning and ignites the hydrogen in the main combustion zone 6 like a perpetual lamp, and the hydrogen fuel in the main combustion zone 6 can be burned at a very low oil-gas ratio, thereby effectively controlling the overall temperature level of the main combustion zone 6, and then controlling the formation of nitrogen oxides. In addition, the combustion product of hydrogen fuel is water, and CO2 will not be generated, which is also beneficial to environmental protection.

[0114] The implementation principle of a dual-zone burner and a combustion method thereof according to an embodiment of the present invention is as follows:

[0115] Methane fuel is injected into the pre-combustion zone 3 through the fuel inlet 1, and then passes through the double tangential blade swirler 2. The blades rotate together to introduce swirl motion to ensure effective mixing of fuel and air. The partition plate separates the blade swirler 2 to improve stability. The pre-combustion zone 3 promotes the initial combustion process and stabilizes the flame. The hydrogen fuel enters through the fuel inlet 24 placed in the tube at the end of the blade swirler 25. The main combustion zone 6 is similar to the pre-combustion zone 3. The main combustion zone 6 also uses a double tangential blade swirler 25 with co-rotating blades and partition plates to achieve optimal fuel-air mixing. The main combustion zone 6 supports the main combustion stage and maintains efficient combustion under different operating conditions. Another set of radial holes 7 in the liner further optimizes air distribution to enhance cooling and emission reduction. The fuel outlet 8 guides the combustion products out of the system.

[0116] The above description is only a preferred embodiment of the present invention and is 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 in the protection scope of the present invention.

Claims

1. A dual-zone burner, characterized in that: The invention comprises a combustion chamber casing, wherein a fuel inlet (1) and a blade swirler (2) are provided on one side of the combustion chamber casing, a fuel inlet (4) and a blade swirler (5) are provided near the middle of the combustion chamber casing, an area between the blade swirler (2) and the blade swirler (5) is a pre-combustion zone (3), an area on the side of the blade swirler (5) away from the pre-combustion zone (3) is a main combustion zone (6), the main combustion zone (6) and the pre-combustion zone (3) are connected to each other, and a fuel outlet (8) is provided on the side of the combustion chamber casing away from the fuel inlet (1).

2. A dual-zone burner according to claim 1, characterized in that: The blade swirler one (2) and the blade swirler two (5) both include rotating blades and partition plates.

3. A dual-zone burner according to claim 1, characterized in that: A bushing is provided inside the combustion chamber casing, the bushing is placed between the main combustion zone (6) and the casing of the combustion chamber casing, and the bushing is provided with radial holes (7).

4. A dual-zone burner and a combustion method thereof according to claim 1, characterized in that: The bushing is made of high temperature resistant material.

5. A combustion method of a dual-zone burner according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: methane fuel is injected into the pre-combustion zone (3) through the fuel inlet 1 (1) and mixed with the swirling air introduced by the blade swirler 1 (2); Step 2: Combustion begins in the pre-combustion zone (3). Turbulence increases the residence time r of the fuel-air mixture, which is calculated as follows: r=L / v Where L is the characteristic length, v is the average velocity, and extending the residence time r can ensure adequate mixing and combustion of methane; Exothermic reactions release heat Q: in is the mass flow rate of methane, ΔH comb is the calorific value of methane; Step 3: Hydrogen fuel is introduced at the end of the blade swirler 2 (5), quickly mixed with the air in the main combustion zone (6), and ignited by the high-temperature combustion gas in the pre-combustion zone (3); Step 4: The velocity path line caused by the vortex follows a spiral trajectory to form an inner recirculation zone IRZ and an outer recirculation zone ORZ, and the hot gas in the recirculation zone maintains combustion; Step 5: The radial holes (7) introduce secondary air, which has a dual function of cooling the inner wall and diluting the combustion gas to adjust the outlet temperature field; Step 6: The fuel outlet (8) effectively delivers the combustion products and ensures a relatively uniform velocity and temperature distribution at the outlet to reduce pressure loss and high temperature erosion of downstream turbine components.

6. A combustion method of a dual-zone burner according to claim 5, characterized in that: In step 1, the blade cyclone 1 (2) imparts a rotational motion, generating a strong centrifugal force, as described below: Where ρ is the air density, v θ is the tangential velocity, r is the radius of the swirl, this centrifugal force forms a central recirculation zone (CRZ) that stabilizes the flame by recirculating the hot combustion products, and the separator ensures symmetry and prevents undesirable flow interactions between the swirls; The methane oxidation reaction rate r is governed by the Arrhenius equation: where A is the pre-exponential factor, Ea is the activation energy, R is the universal gas constant, T is the temperature, and are the concentrations of methane and oxygen, respectively.

7. A combustion method of a dual-zone burner according to claim 5, characterized in that: In step three, hydrogen mixes faster than methane due to its lower molecular weight and higher diffusion rate. Its low ignition delay and wide flammability range make it ideal for lean burn combustion. The flame propagation speed SL is given by the following formula: S L =αT β P α f(T, P) where T and P are the local temperature and pressure, α and β depend on the fuel type, and f(T, P) is a function that captures the nonlinear effects of temperature and pressure on flame speed. The main combustion zone operates at a lean fuel-air ratio to suppress NOx emissions primarily through the Zeldovich mechanism: O+N2→NO+N N+O2→NO+O N+OH→NO+H The vane swirler two (5) design creates a secondary circulation zone that stabilizes the flame over a wide range of operating conditions.

8. A combustion method of a dual-zone burner according to claim 5, characterized in that: In step 4, the turbulent kinetic energy K in the flow is expressed as: where u 2 、v 2 and w 2 These are the velocity fluctuations in the x, y and z directions, respectively. The strong shear layer at the interface between the inner recirculation zone IRZ and the outer recirculation zone ORZ enhances turbulent mixing.

9. A combustion method of a dual-zone burner according to claim 5, characterized in that: In step 5, the convective heat transfer rate Q for cooling conv It is given by the following formula: Q conv =hA(T 气体 +T 墙 ) Where h is the heat transfer coefficient, A is the surface area, T 气体 is the gas temperature, T 墙 The secondary air forms an air film to lower the wall temperature, protecting the inner wall from thermal stress and reducing the peak flame temperature, thereby minimizing the formation of NOx.

10. A combustion method of a dual-zone burner according to claim 5, characterized in that: In step six, the total pressure loss ΔP in the combustion chamber is: Where f is the Darcy friction coefficient, which depends on the Reynolds number and the pipe roughness; L is the length of the pipe or conduit; D is the hydraulic diameter of the pipe or conduit; p is the fluid density; and v is the average flow velocity.

Images