LOW-EMISSION COMBUSTOR HEAD STRUCTURE WITH V-SHAPED TRAILING EDGE VANE

Description

CROSS REFERENCE TO THE RELATED APPLICATIONS

This application is based upon and claims priority to Chinese Patent Application No. 202411577361.2, filed on Nov. 6, 2024, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of staged low-emission combustors for gas turbines, and in particular to a low-emission combustor head structure with a V-shaped trailing edge vane.

BACKGROUND

The pollutant emissions of gas turbines originate from the combustor. Therefore, developing low-emission combustion technology is a key to reducing the pollutant emissions of gas turbines. The main pollutants from the combustor include nitrogen oxides (NOx), carbon monoxide (CO), and unburned hydrocarbons (UHC), among which reducing NOx emissions is of paramount importance. The generation mechanism of thermal NOx plays a dominant role in the combustor, so reducing the combustion temperature in the combustion zone is one of the effective means to reduce NOx emissions. Lean combustion technology can effectively lower the combustion temperature in the combustion zone, thereby reducing NOx emissions. The ability of advanced low-emission combustors to reduce pollutant emissions is largely attributed to the advanced head design for combustion management. For lean low-emission combustors, due to the need for air staging and fuel staging combustion, most advanced low-emission combustor nozzles primarily include a pilot stage nozzle (centrifugal type) and a main stage nozzle (direct injection type). For lean combustion technology, foreign researchers have proposed lean premixed prevaporized (LPP) combustion technology and conducted extensive research on it. This technology can effectively control the combustion temperature in the main combustion zone and has great potential in reducing NOx emissions.

General Electric (GE) has already filed many United States (US) patents for twin annular premixing swirler (TAPS) combustors. The technical solutions proposed in low-emission combustor head patents, such as U.S. Pat. Nos. 6,453,660B1, 6,381,964B1, and 6,389,815B1, are as follows. The pilot stage includes a centrifugal nozzle, a two-stage axial swirler, a venturi, and a sleeve. The main stage includes a direct injection nozzle and a one-or two-stage radial swirler. The large head nozzle includes a pilot stage single-fuel-circuit centrifugal nozzle and a main stage direct injection nozzle. Beihang University and China Gas Turbine Establishment (CGTE) have also filed patents for various LPP combustors, such as CN101169252A, CN101275751A, CN101275750A, CN202032612U, CN202032613U, and CN202082953U. NOx is one of the pollutants that gas turbine combustor designers need to focus on. In the combustor, NOx is primarily determined by the flame temperature in the combustion zone and the gas residence time. Existing low-emission combustors adopt centrally-staged LPP combustion technology to reduce the pollutant emissions. The head of the low-emission combustor is divided into a pilot stage and a main stage surrounding the pilot stage. The head requires good mixing of fuel and air to achieve good low-emission effects. The fuel and air need to mix within a limited spatial distance. In the prior art, transverse fuel jet injection is often used to achieve desired atomization and mixing effects. However, the transverse jet penetration depth is greatly related to the fuel-air momentum ratio. The transverse jet penetration depth varies under different operating conditions of the gas turbine. This causes uneven radial fuel distribution and deviation of fuel atomization effects from design requirements, leading to issues such as high pollutant emissions and incomplete combustion.

SUMMARY

In view of the aforementioned problems of existing combustors, such as uneven radial fuel distribution, poor fuel atomization, high pollutant emissions, and incomplete combustion, an objective of the present disclosure is to provide a low-emission combustor head structure with a V-shaped trailing edge vane.

To achieve the above objective, the present disclosure adopts the following technical solution.

A low-emission combustor head structure with a V-shaped trailing edge vane includes: a main stage, a pilot stage, a heat shield 12, and a flame tube 13, where the main stage and the pilot stage are arranged coaxially; the pilot stage is connected to a middle portion of a front end of the main stage; an outer edge of a rear end of the main stage is connected to the flame tube 13 through the heat shield 12; the rear end of the main stage, the heat shield 12, and the flame tube 13 enclose to form a combustor; and the main stage is configured to inject fuel into the combustor.

The aforementioned low-emission combustor head structure with a V-shaped trailing edge vane further includes: fuel conduits 11, including one fuel conduit 11 configured to deliver the fuel to the pilot stage and the other fuel conduit 11 configured to deliver the fuel to the main stage.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the pilot stage includes: a pilot stage swirler inner ring 7 and a centrifugal nozzle 10; the centrifugal nozzle 10 is disposed inside a rear end of the pilot stage swirler inner ring 7; and the one fuel conduit 11 communicates with a front end of the pilot stage swirler inner ring 7.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the front end of the pilot stage swirler inner ring 7 is circumferentially provided with a plurality of purge flow passages 9; and the plurality of purge flow passages 9 all communicate with the combustor.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the main stage includes: a main stage outer ring 1 and a main stage inner ring 5; the main stage outer ring 1 and the main stage inner ring 5 are arranged coaxially; an outer edge of a rear end of the main stage outer ring 1 is connected to the flame tube 13 through the heat shield 12; a main stage annular fuel manifold 6 is disposed inside the main stage inner ring 5; and the other fuel conduit 11 communicates with the main stage annular fuel manifold 6.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the pilot stage further includes: swirler vanes 8; an inner wall of the main stage inner ring 5 and an outer wall of the rear end of the pilot stage swirler inner ring 7 are connected by the plurality of swirler vanes 8; and the plurality of swirler vanes 8 are arranged circumferentially at equal intervals around an axis of the pilot stage swirler inner ring 7.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the main stage further includes: main stage swirler vanes 2 and main stage V-shaped trailing edge vanes 3; an outer wall of the main stage inner ring 5 and an inner wall of the main stage outer ring 1 are connected by the plurality of main stage swirler vanes 2 and the plurality of main stage V-shaped trailing edge vanes 3; the plurality of main stage swirler vanes 2 are arranged circumferentially at equal intervals around the axis of the pilot stage swirler inner ring 7; the plurality of main stage V-shaped trailing edge vanes 3 are arranged circumferentially at equal intervals around the axis of the pilot stage swirler inner ring 7; and one main stage V-shaped trailing edge vane 3 is disposed between any two adjacent main stage swirler vanes 2.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, each of the swirler vanes 8 is internally provided with a first swirling flow passage; and one end of the first swirling flow passage communicates with an interior of the pilot stage swirler inner ring 7, and the other end of the first swirling flow passage communicates with the main stage annular fuel manifold 6.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the main stage V-shaped trailing edge vane 3 is provided with at least one main stage fuel injection hole 4; a third flow passage communicates with the combustor through the main stage fuel injection hole 4; and each main stage fuel injection hole 4 is located inside a V-shaped groove.

In the aforementioned low-emission combustor head structure with a V-shaped trailing edge vane, the heat shield 12 is provided with a plurality of cooling orifices distributed circumferentially; an axis of each of the cooling orifices and an axis of the pilot stage form an angle of 0-30°; the cooling orifices each have a diameter of 0.4-0.6 mm; and there are 150-300 cooling orifices.

With the above technical solutions, the present disclosure has the following positive effects compared with the prior art.

• • (1) The present disclosure adopts an oblique radial swirler and lean premixed prevaporized technology for the main stage. The oblique radial swirler combines the advantages of low flow resistance of axial swirlers and short axial length of radial swirlers. The main stage swirler vanes and the main stage V-shaped trailing edge vanes are arranged alternately. A recirculation vortex is formed downstream of the main stage V-shaped trailing edge vanes. The main stage fuel injection holes are arranged within the V-shaped grooves of the main stage V-shaped trailing edge vanes. The main stage fuel is injected from the main stage fuel injection holes into the recirculation vortex formed downstream of the main stage V-shaped trailing edge vanes. The velocity difference formed by the two sharp edges of the main stage V-shaped trailing edge vanes enhances fuel droplet breakup. The recirculation vortex enhances the mixing of the atomized fuel downstream of the nozzles. The co-flow injection mode effectively prevents the fuel droplets from commonly used transverse jets from colliding with the swirler wall structure, avoiding droplet accumulation. It also ensures the uniformity of the air flow at the main stage outlet, which is conducive to uniform combustion.
  • (2) The present disclosure adopts a design where the tail end of the venturi diffuser section is flush with the height of the main stage inner ring. The inter-stage section of aero-engines typically has a step structure with a height of about 3-5 mm. A step recirculation zone is formed through the inter-stage structure, which helps to widen the lean blowout limit range. Since gas turbine combustors have lower requirements for the lean blowout limit range compared to aero-engine combustors, forming a step recirculation zone is unnecessary. The design of the present disclosure avoids forming a step recirculation zone, reduces pressure losses, and avoids the ablation of the inter-stage section and the outlet of the main stage inner ring caused by the high-temperature zone formed by the step recirculation zone, extending the service life of the head.
  • (3) The present disclosure adopts a staged combustion concept. The pilot stage provides a stable ignition source, and the main stage achieves low-emission combustion. This ensures combustor stability while reducing pollutant emissions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of an integrated head of a low-emission combustor head structure with a V-shaped trailing edge vane according to the present disclosure;

FIG. 2 is a structural diagram of an integrated fuel nozzle of the low-emission combustor head structure with a V-shaped trailing edge vane according to the present disclosure;

FIG. 3 is a partially enlarged view of the integrated fuel nozzle shown in FIG. 2; and

FIG. 4 is an assembly diagram of the integrated head and a flame tube of the low-emission combustor head structure with a V-shaped trailing edge vane according to the present disclosure.

Reference Numerals: 1. main stage outer ring; 2. main stage swirler vane; 3. main stage V-shaped trailing edge vane; 4. main stage fuel injection hole; 5. main stage inner ring; 6. main stage annular fuel manifold; 7. pilot stage swirler inner ring; 8. swirler vane; 9. purge flow passage; 10. centrifugal nozzle; 11. fuel conduit; 12. heat shield; and 13. flame tube.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure is further described below with reference to the drawings and specific embodiments, but the present disclosure is not limited thereto.

FIG. 1 to FIG. 4 show a low-emission combustor head structure with a V-shaped trailing edge vane, including: a main stage, a pilot stage, heat shield 12, and flame tube 13. The main stage and the pilot stage are arranged coaxially. The pilot stage is connected to a middle portion of a front end of the main stage. An outer edge of a rear end of the main stage is connected to the flame tube 13 through the heat shield 12. The rear end of the main stage, the heat shield 12, and the flame tube 13 enclose to form a combustor. The main stage is configured to inject fuel into the combustor.

Furthermore, in a preferred embodiment, the low-emission combustor head structure further includes fuel conduits 11, including one fuel conduit 11 configured to deliver the fuel to the pilot stage and the other fuel conduit 11 configured to deliver the fuel to the main stage.

Furthermore, in a preferred embodiment, the pilot stage includes pilot stage swirler inner ring 7 and centrifugal nozzle 10. The centrifugal nozzle 10 is disposed inside a rear end of the pilot stage swirler inner ring 7. One fuel conduit 11 communicates with a front end of the pilot stage swirler inner ring 7.

Furthermore, in a preferred embodiment, the front end of the pilot stage swirler inner ring 7 is circumferentially provided with a plurality of purge flow passages 9. The plurality of purge flow passages 9 all communicate with the combustor.

Furthermore, in a preferred embodiment, the main stage includes main stage outer ring 1 and main stage inner ring 5. The main stage outer ring 1 and the main stage inner ring 5 are arranged coaxially. An outer edge of a rear end of the main stage outer ring 1 is connected to the flame tube 13 through the heat shield 12. The main stage inner ring 5 is internally provided with main stage annular fuel manifold 6. The other fuel conduit 11 communicates with the main stage annular fuel manifold 6.

Furthermore, in a preferred embodiment, the pilot stage further includes swirler vanes 8. An inner wall of the main stage inner ring 5 and an outer wall of the rear end of the pilot stage swirler inner ring 7 are connected by the plurality of swirler vanes 8. The plurality of swirler vanes 8 are arranged circumferentially at equal intervals around an axis of the pilot stage swirler inner ring 7.

Furthermore, in a preferred embodiment, the main stage further includes main stage swirler vanes 2 and main stage V-shaped trailing edge vanes 3. An outer wall of the main stage inner ring 5 and an inner wall of the main stage outer ring 1 are connected by the plurality of main stage swirler vanes 2 and the plurality of main stage V-shaped trailing edge vanes 3. The plurality of main stage swirler vanes 2 are arranged circumferentially at equal intervals around the axis of the pilot stage swirler inner ring 7. The plurality of main stage V-shaped trailing edge vanes 3 are arranged circumferentially at equal intervals around the axis of the pilot stage swirler inner ring 7. One main stage V-shaped trailing edge vane 3 is disposed between any two adjacent main stage swirler vanes 2.

Furthermore, in a preferred embodiment, each of the swirler vanes 8 is internally provided with a first swirling flow passage. One end of the first swirling flow passage communicates with an interior of the pilot stage swirler inner ring 7, and the other end of the first swirling flow passage communicates with the main stage annular fuel manifold 6.

Furthermore, in a preferred embodiment, the main stage V-shaped trailing edge vane 3 is provided with at least one main stage fuel injection hole 4. A third flow passage communicates with the combustor through the main stage fuel injection hole 4. Each main stage fuel injection hole 4 is located inside a V-shaped groove.

Furthermore, in a preferred embodiment, the heat shield 12 is provided with a plurality of cooling orifices distributed circumferentially. An axis of each of the cooling orifices and an axis of the pilot stage form an angle of 0-30°. The cooling orifices each have a diameter of 0.4-0.6 mm, and there are 150-300 cooling orifices.

The above are only preferred embodiments of the present disclosure and do not thereby limit the implementation and protection scope of the present disclosure.

The present disclosure further includes following implementations on the above basis.

In a further embodiment of the present disclosure, the present disclosure provides a low-emission combustor head structure with a V-shaped trailing edge vane. The low-emission combustor head structure includes a pilot stage and a main stage, etc. The pilot stage includes a swirler, a venturi, and centrifugal nozzle 10. The main stage includes an oblique radial swirler, main stage swirler vanes 2, main stage V-shaped trailing edge vanes 3, main stage annular fuel manifold 6, and main stage fuel injection holes 4. The main stage fuel injection holes 4 are direct injection nozzles. The oblique radial swirler of the main stage includes main stage outer ring 1, main stage swirler vanes 2, and main stage inner ring 5. The oblique radial swirler combines the advantages of radial and axial swirlers, ensuring swirl intensity while reducing the axial length of the swirler head. The main stage uses discrete multi-point direct injection nozzles for initial pressure atomization. Fuel droplet breakup and mixing are enhanced through the V-shaped trailing edge structure. The fuel is fully premixed downstream of the main stage V-shaped trailing edge vanes 3, which greatly reduce pollutant emissions, thereby achieving ultra-low emissions. The combustor head structure is designed as an integrated structure, facilitating replacement and maintenance.

In a further embodiment of the present disclosure, the present disclosure proposes a low-emission combustor head structure with a V-shaped trailing edge vane. This head enables the combustor to operate stably and efficiently across an entire operating range, effectively inhibiting combustion instability. Meanwhile, this solution has advantages such as compact structure, smooth transition between operating conditions, high-uniformity outlet temperature field, wide operating range, high combustion stability, low emissions, strong load adaptability, and applicability in both light-duty and heavy-duty gas turbines.

In a further embodiment of the present disclosure, FIG. 1 and FIG. 2 show cross-sectional views of the low-emission combustor head structure with a V-shaped trailing edge vane according to an implementation of the present disclosure. As shown in FIG. 1 and FIG. 2, direct injection/centrifugal nozzles and a central staging structure are adopted. The main stage fuel injection holes 4 are direct injection nozzles. The centrifugal nozzle is the centrifugal nozzle 10. The main stage includes main stage outer ring 1, main stage swirler vanes 2, main stage V-shaped trailing edge vanes 3, main stage fuel injection holes 4, main stage inner ring 5, and main stage annular fuel manifold 6. The pilot stage includes pilot stage swirler inner ring 7, swirler vanes 8, purge flow passages 9, and the centrifugal nozzle 10. The head structure further includes fuel conduits 11 and heat shield 12. The pilot stage is connected to the main stage through the main stage inner ring 5 and is concentric with the main stage. The main stage swirler vanes 2 and the main stage V-shaped trailing edge vanes 3 are arranged alternately. A recirculation vortex is formed downstream of the main stage V-shaped trailing edge vanes 3. The main stage fuel injection holes 4 are disposed inside V-shaped grooves of the V-shaped trailing edge vanes. The main stage fuel is injected from the main stage fuel injection holes 4 into the recirculation vortex formed downstream of the V-shaped trailing edge vanes. After being ejected from the main stage fuel injection holes 4, the fuel is fully mixed with air in the main stage premixing passage. The pilot stage fuel forms fuel mist through the centrifugal nozzle 10, and enables diffusion combustion at a pilot stage outlet.

In a further embodiment of the present disclosure, the main stage adopts an oblique radial swirler structure. It includes 8 to 16 main stage swirler vanes 2 uniformly distributed circumferentially, with a thickness of 1.0-4.0 mm, and 8 to 16 main stage V-shaped trailing edge vanes 3 uniformly distributed circumferentially, with a thickness of 3.0-8.0 mm and a V-shaped angle of 45-120° at a trailing edge. The main stage swirler vanes 2 and the main stage V-shaped trailing edge vanes 3 are arranged alternately and are equal in number. The main stage swirler vanes 2 have a longer axial length than the main stage V-shaped trailing edge vanes 3. A swirl number of 0.5-1.5 is configured to form swirling air. A main stage swirler inlet and a combustor centerline form an angle of 30-60°. Swirlers have spacing of 25-35 mm and an axial length of 50-60 mm.

In a further embodiment of the present disclosure, the pilot stage swirler includes 8-12 swirler vanes 8 uniformly distributed circumferentially, with a thickness of 2-10 mm and a swirl number of 0.5-1.5 configured to form strong swirl. The swirl intensity is calculated through empirical equations. Experiments prove that the strong swirl obtained with this vane arrangement can effectively improve combustion efficiency at low load conditions. The vane thickness is obtained based on the effective flow area of the pilot stage swirler. The flow area is obtained based on the allocated proportion of the pilot stage air flow rate.

In a further embodiment of the present disclosure, the pilot stage centrifugal nozzle 10 has an injection cone angle of 60-90°. If the injection cone angle is too small, the atomization effect is poor. If the injection cone angle is too large, fuel droplets will impact a contraction section of the main stage inner ring 5, causing droplets to splash upstream. The main stage fuel injection holes 4 are direct injection nozzles. The main stage fuel injection holes 4 are arranged within the V-shaped grooves of the main stage V-shaped trailing edge vanes 3. The arrangement position of the main stage fuel injection holes 4 is at 10-90% of the height of the V-shaped grooves. The main stage V-shaped trailing edge vane 3 is provided with 1-2 main stage fuel injection holes 4. The main stage fuel injection holes 4 have a diameter of 0.01-0.8 mm. The number and diameter of the main stage fuel injection holes 4 are selected according to the fuel flow rate at the combustor design condition. The injection direction has an angle of 0-30° with the axial direction. The injection direction is the same as the swirling air direction. If the injection angle is too large, the fuel may splash onto the main stage inner ring 5 to cause coking. The main stage fuel injection holes 4 are supplied with fuel through the annular fuel manifold. The main stage annular fuel manifold 6 is disposed inside the main stage inner ring 5. The fuel manifold ring has a radial width of 2 to 6 mm and an axial length of 20-35 mm. The proportion of the main stage fuel to the total fuel is 50-100%. There is an axial distance of 10-20 mm between the main stage fuel injection holes 4 and the swirler outlet. The sufficient axial distance ensures full mixing of the fuel and air. Under the action of the V-shaped groove, a vortex is formed downstream of the vane. The main stage fuel injection holes 4 using this structural scheme can inject the fuel into the vortex formed downstream of the V-shaped groove. Compared to the scheme of directly injecting the fuel into the co-flowing air, the disturbance and shear action of the vortex can enhance the mixing effect of the fuel and air.

In a further embodiment of the present disclosure, the main stage, the pilot stage, the fuel conduits 11, and the heat shield 12 constitute the low-emission combustor head structure. The heat shield 12 and the flame tube 13 form a clearance fit. The heat shield 12 includes circumferentially distributed cooling orifices for cooling air flow. The angle between the axis of each of the cooling orifices and the combustor centerline direction is 10-30°. The orifices have a diameter of 0.4-0.6 mm, and there are 150-300 orifices. A small angle can achieve a uniform cooling film on the heat shield 12, avoiding high-temperature ablation of the heat shield 12. The diameter and number of the orifices are adjustable according to the cooling air flow rate allocated to the combustor.

In a further embodiment of the present disclosure, the working principle of the present disclosure is as follows. The main stage adopts LPP combustion technology. The main stage swirler vanes 2 and the main stage V-shaped trailing edge vanes 3 are arranged alternately. A recirculation vortex is formed downstream of the main stage V-shaped trailing edge vanes 3. The main stage fuel injection holes 4 are arranged within the V-shaped grooves of the main stage V-shaped trailing edge vanes 3. The main stage fuel is injected from the main stage fuel injection holes 4 into the recirculation vortex formed downstream of the main stage V-shaped trailing edge vanes 3. The velocity difference formed by the two sharp edges of the main stage V-shaped trailing edge vanes 3 enhances fuel droplet breakup. The recirculation vortex enhances the mixing of the atomized fuel downstream of the nozzles. After being ejected from the main stage fuel injection holes 4, the fuel is fully mixed with air in the main stage premixing passage, which greatly reduces the emissions of pollutants such as nitrogen oxides (NOx), unburned hydrocarbons (UHC), carbon monoxide (CO), and soot particles. The design of the main stage swirler considers preventing flashback and auto-ignition phenomena. By using the oblique radial swirler and controlling the equivalent flow area of the oblique section to be greater than that of the straight section, the main stage air flow is accelerated. This combines the advantages of low flow resistance of axial swirlers and short axial length of radial swirlers. The pilot stage adopts a diffusion combustion mode, ensuring stable operation of the combustor at low load conditions while enhancing the ignition performance of the combustor. The design of the combustor head considers air intake uniformity, aerodynamic atomization of the main stage fuel, and head assembly/disassembly issues. The flame tube 13 and the head have a clearance fit. The integrated head nozzle structure does not require disassembling the flame tube 13 during mounting and maintenance. The clearance fit allows separation of the head and the flame tube 13 without tools, providing high practical value. NOx emissions are maintained below 50 ppm within the operating condition range of 0.5-1.0.

In a further embodiment of the present disclosure, the present disclosure adopts an oblique radial swirler and lean premixed prevaporized technology for the main stage. The oblique radial swirler combines the advantages of low flow resistance of axial swirlers and short axial length of radial swirlers. The main stage swirler vanes 2 and the main stage V-shaped trailing edge vanes 3 are arranged alternately. A recirculation vortex is formed downstream of the main stage V-shaped trailing edge vanes 3. The main stage fuel injection holes 4 are arranged within the V-shaped grooves of the main stage V-shaped trailing edge vanes 3. The main stage fuel is injected from the main stage fuel injection holes 4 into the recirculation vortex formed downstream of the main stage V-shaped trailing edge vanes 3. The velocity difference formed by the two sharp edges of the main stage V-shaped trailing edge vanes 3 enhances fuel droplet breakup. The recirculation vortex enhances the mixing of the atomized fuel downstream of the nozzles. The co-flow injection mode effectively prevents the fuel droplets from commonly used transverse jets from colliding with the swirler wall structure, avoiding droplet accumulation. It also ensures the uniformity of the air flow at the main stage outlet, which is conducive to uniform combustion.

In a further embodiment of the present disclosure, the present disclosure adopts a design where the tail end of the venturi diffuser section is flush with the height of the main stage inner ring 5. The inter-stage section of aero-engines typically has a step structure with a height of about 3-5 mm. A step recirculation zone is formed through the inter-stage structure, which helps to widen the lean blowout limit range. Since gas turbine combustors have lower requirements for the lean blowout limit range compared to aero-engine combustors, forming a step recirculation zone is unnecessary. The design of the present disclosure avoids forming a step recirculation zone, reduces pressure losses, and avoids the ablation of the inter-stage section and the outlet of the main stage inner ring 5 caused by the high-temperature zone formed by the step recirculation zone, extending the service life of the head.

In a further embodiment of the present disclosure, the present disclosure adopts a staged combustion concept. The pilot stage provides a stable ignition source, and the main stage achieves low-emission combustion. This ensures combustor stability while reducing pollutant emissions.

In a further embodiment of the present disclosure, the fuel enters the pilot stage centrifugal nozzle 10 from the fuel conduit 11. The fuel is atomized by the centrifugal nozzle 10 to form fuel mist entering the combustor for combustion. The fuel conduit 11 and the pilot stage centrifugal nozzle 10 are connected by means of a thread. The centrifugal nozzle 10 can be disassembled separately for replacement. The size of the connection thread is smaller than the outer pipe diameter of the fuel conduit 11 and the centrifugal nozzle 10. The inner pipe diameter at the connection is selected according to the thread size to reduce machining difficulty. The internal pipe structure of the centrifugal nozzle 10 is selected according to the operating conditions and equipment situation.

The above embodiments are merely preferred examples of the present disclosure, which are not intended to limit the implementation and protection scope of the present disclosure. It should be noted by those skilled in the art that all equivalent replacements and obvious changes made by using the description of the present disclosure and the content of the drawings should be included in the protection scope of the present disclosure.