Gas turbine engine and its mixing assembly, combustion chamber, and fuel atomization method

Abstract

This invention provides a gas turbine engine and a mixer assembly, combustion chamber, and fuel atomization method therefor. The mixer assembly includes a main combustion mixer, which comprises: an annular channel with an inlet end and an outlet end, the inlet end for air intake and the outlet end for exhausting a fuel-air mixture; the annular channel also includes a first inner wall surface and a first outer wall surface, which together constitute the fuel-air mixing space of the main combustion mixer; fuel nozzles, multiple fuel nozzles distributed circumferentially on the first inner wall surface for injecting fuel into the annular channel; and a turbulence generating structure disposed circumferentially on the first inner wall surface, located upstream of the fuel nozzles. This achieves the effect of increasing the fuel distribution area.

Description

Technical Field

[0001] This invention relates to the field of aero engines, and more particularly to gas turbine engines and mixer assemblies, combustion chambers, and fuel atomization methods therefor. Background Technology

[0002] The basic performance and structural design of modern aero-engine combustors have been continuously optimized. The development trend is towards a continuous shortening of axial length and a continuous increase in the height of the head (mixer assembly), ultimately resulting in a shorter annular shape for the combustor. Whether in military or civil aero-engines, the large air intake at the combustor head means that the combustion organization largely depends on the aerodynamic design of the head, i.e., the matching of fuel and air before combustion, which further affects combustion efficiency, outlet temperature distribution, emissions, combustion stability, and other performance characteristics. Summary of the Invention

[0003] The object of this invention is to provide a mixer assembly for a gas turbine engine.

[0004] Another object of the present invention is to provide a burner for a gas turbine engine.

[0005] Another object of the present invention is to provide a gas turbine engine.

[0006] Another object of the present invention is to provide a method for atomizing fuel for a gas turbine engine.

[0007] According to one aspect of the present invention, a mixer assembly for a gas turbine engine includes a main combustion mixer, the main combustion mixer comprising: an annular channel including an inlet end and an outlet end, the inlet end for receiving air and the outlet end for discharging a fuel-air mixture; the annular channel further comprising a first inner wall surface and a first outer wall surface, the first inner wall surface and the first outer wall surface together constituting a fuel-air mixing space of the main combustion mixer; fuel nozzles, a plurality of fuel nozzles being circumferentially distributed on the first inner wall surface for injecting fuel into the annular channel; and a turbulence generating structure being circumferentially disposed on the first inner wall surface, located upstream of the fuel nozzles.

[0008] The technical solution of this application sets up a turbulence generating structure upstream of the fuel injection hole to reduce the velocity of the boundary layer airflow downstream of the turbulence generating structure and increase the turbulence intensity. A low-speed, high-turbulence airflow zone is formed downstream of the turbulence generating structure. The airflow in this low-speed, high-turbulence zone can affect the trajectory of the fuel ejected from the fuel injection hole, making the injected fuel have stronger penetrating power and promoting mixing with air. At the same time, it can also cause the fuel to move towards the wall of the annular channel, thereby increasing the fuel distribution area downstream of the main combustion mixer. This achieves the effects of reducing fuel enrichment, reducing fuel combustion temperature, improving combustion efficiency, and reducing pollutant emissions.

[0009] In one or more embodiments of the mixer assembly, the main combustion mixer further includes swirl vanes arranged circumferentially within the annular channel, the swirl vanes being staggered with the fuel injection orifices.

[0010] In one or more embodiments of the mixer assembly, the turbulence generating structure includes a protrusion extending radially outward from the first inner wall and / or a recess extending radially inward from the first inner wall.

[0011] In one or more embodiments of the mixer assembly, the radial height and axial width of the protrusion or recess are less than or equal to 1 / 5 of the radial height of the annular channel.

[0012] In one or more embodiments of the mixer assembly, the convex or concave portion is axially spaced from the fuel injection orifice at a distance of 5 to 15 times the diameter of the fuel injection orifice.

[0013] In one or more embodiments of the mixer assembly, the protrusions may be continuous ridges or multiple discrete bosses distributed circumferentially, and the recesses may be continuous grooves or multiple discrete pits distributed circumferentially.

[0014] In one or more embodiments of the mixer assembly, a radial section of the annular channel is located at one of the fuel injection holes, and the distribution of fuel ejected from the fuel injection holes on the radial section includes an upper boundary and a lower boundary. The upper boundary includes a first inflection point and a second inflection point, the first inflection point being located on the same centerline as the fuel injection hole. The lower boundary includes a third inflection point and a fourth inflection point, such that the lower boundary is close to the first inner wall surface.

[0015] In one or more embodiments of the mixer assembly, the main combustion mixer further includes an annular cavity for fuel flow to the fuel injection orifice, the annular channel at least partially surrounding the annular cavity, the annular cavity including a second inner wall surface and a second outer wall surface, the second inner wall surface constituting the inner wall surface of the main combustion mixer, and the second outer wall surface constituting the first inner wall surface.

[0016] In one or more embodiments of the mixer assembly, the radially upstream side of the annular cavity further includes an end cap; the main combustion mixer also includes a fuel line that is fluidly connected to the annular cavity via the end cap to deliver fuel to the annular cavity.

[0017] The mixer assembly further includes a pre-combustion mixer, which is at least partially surrounded by the main combustion mixer.

[0018] According to another aspect of the invention, a combustion chamber for a gas turbine engine includes: a mixer assembly as described above; a combustion vessel; wherein a downstream end of the mixer assembly is in communication with the combustion vessel to provide a flow of a fuel-air mixture to the combustion vessel.

[0019] According to another aspect of the present invention, a gas turbine engine includes a combustion chamber as described above.

[0020] According to another aspect of the present invention, a method for atomizing fuel for a gas turbine engine includes: providing a main combustion mixer, the main combustion mixer being configured such that: a turbulence generating structure is provided upstream of a fuel injection orifice located on the inner wall of an annular channel of the main combustion mixer; a first airflow enters the annular channel of the main combustion mixer, flows through the turbulence generating structure, reduces the local airflow velocity, increases the turbulence intensity to form a second airflow; the fuel injection orifice injects fuel into the annular channel; and the second airflow mixes with the fuel. Attached Figure Description

[0021] The above and other features, properties, and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features. It should be noted that these drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the scope of protection actually claimed by the present invention, wherein:

[0022] Figure 1 This is a schematic diagram of the combustion chamber structure of one embodiment;

[0023] Figure 2 This is a schematic diagram of the structure of a main combustion mixer according to one embodiment;

[0024] Figure 3A This is a schematic diagram of the fuel distribution structure in a ring-shaped channel for a comparative scheme;

[0025] Figure 3B This is a schematic diagram of the fuel distribution structure in an annular channel according to one embodiment;

[0026] Figure 4A A schematic diagram of the fuel distribution area on the axial section γ of the annular channel in a comparative scheme;

[0027] Figure 4B This is a schematic diagram of the fuel distribution region on the axial section γ of an annular channel according to an embodiment.

[0028] Figure 5A This is a schematic diagram of the fuel distribution structure of the rectangular channel in the circumferential direction of the annular channel in a comparative scheme.

[0029] Figure 5B This is a schematic diagram of the fuel distribution structure of a rectangular channel in the circumferential direction of an annular channel according to an embodiment.

[0030] Figure 6A A schematic diagram of the fuel distribution area on the circumferential section β of a rectangular channel for a comparative scheme;

[0031] Figure 6B This is a schematic diagram of the fuel distribution region on the circumferential section β of a rectangular channel according to an embodiment;

[0032] Figure 7A This is a schematic diagram of the fuel distribution on the axial section θ of the annular channel in a comparative scheme;

[0033] Figure 7B This is a schematic diagram of the fuel distribution on the axial section θ of an annular channel according to one embodiment;

[0034] Figure 8A This is a schematic diagram of the airflow velocity distribution on the axial section θ of the annular channel in a comparative scheme.

[0035] Figure 8B This is a schematic diagram of the airflow velocity distribution on the axial section θ of an annular channel according to an embodiment;

[0036] Figures 9A to 9D Schematic diagrams of turbulence generating structures with square radial cross-sections in different embodiments;

[0037] Figures 10A to 10D Schematic diagrams of turbulence generating structures with trapezoidal radial cross-sections in different embodiments;

[0038] Figures 11A to 11D Schematic diagrams of turbulence generating structures with triangular radial cross-sections in different embodiments;

[0039] Figures 12A to 12D Schematic diagrams of turbulence generating structures with a semi-circular radial cross-section in different embodiments;

[0040] Figure 13 This is a schematic diagram of the structure of a gas turbine engine according to one embodiment.

[0041] Figure label:

[0042] 1000 - Gas turbine engine, 300 - Fan, 400 - Low-pressure compressor, 500 - High-pressure compressor, 600 - High-pressure turbine, 700 - Low-pressure turbine, 800 - Fan casing;

[0043] 2000 - Combustion chamber, 100 - Mixer assembly, 200 - Combustion vessel;

[0044] 1001 - Main combustion mixer;

[0045] 1-Annular channel, 101-Entrance end, 102-Exit end, 103-First inner wall surface, 104-First outer wall surface, 11-Rectangular channel;

[0046] 2-Fuel injection hole, 21-Upper boundary, 201-First inflection point, 202-Second inflection point, 22-Lower boundary, 203-Third inflection point, 204-Fourth inflection point, 20, 20'-Fuel, 23, 23', 24-Low speed zone;

[0047] 3-Turbulence generating structure, 31-Protrusion, 311-Protrusion strip, 312-Boss, 32-Concave part, 321-Groove, 322-Pit;

[0048] 4-Swirl blades;

[0049] 5-Annular cavity, 501-Second inner wall surface, 502-Second outer wall surface, 503-End cap;

[0050] 6-Fuel pipe, 7-Diffuser, 8-Oil cap, 9-Outer combustion chamber casing, 10-Inner combustion chamber casing. Detailed Implementation

[0051] Reference will now be made in detail to various embodiments of the invention, examples of which are shown in the accompanying drawings and described below. Although the invention will be described in conjunction with exemplary embodiments, it should be understood that this specification is not intended to limit the invention to those exemplary embodiments. Rather, the invention is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0052] In the following description, the orientation or positional relationship indicated by terms such as "radial," "axial," "circumferential," "upstream," "downstream," "inner," "outer," or other directional terms is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, "upstream" and "downstream" are distinguished based on the direction of airflow, for example, airflow from upstream to downstream.

[0053] Furthermore, this application uses specific terms to describe its embodiments. For example, "an embodiment" and / or "one embodiment" refers to a particular feature, structure, or characteristic associated with at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0054] With increasingly stringent requirements for the emissions and performance of gas turbine engines, further improvements to the structure of gas turbine engines are needed.

[0055] like Figure 13 The diagram shows the conventional structure of a gas turbine engine. From upstream to downstream, it consists of a fan 300, a low-pressure compressor 400, a high-pressure compressor 500, a combustion chamber 2000, a high-pressure turbine 600, and a low-pressure turbine 700. A fan casing 800 is located outside the fan 300. To accommodate a wide operating range, the combustion chamber inlet temperature of the gas turbine engine can exceed 900K, and the inlet pressure can exceed 40 atm. The combustion chamber employs multiple air intakes and fuel injections at multiple points in the head, forming a multi-swirling flame. Fuel injection can be divided into staged injection and single-stage multi-position injection. A typical staged injection combustion method involves setting a pre-combustion stage at the center of the combustion chamber head and a main combustion stage at the outer edge of the center. This allows the pre-combustion stage to inject a small flow of fuel in a diffusion combustion mode when the thrust is low, ensuring combustion efficiency and ignition performance. When the thrust is medium to high, the pre-combustion stage and the main combustion stage inject fuel simultaneously. Most of the fuel is injected into the combustion chamber through the main combustion stage and operates in a partially premixed combustion mode, thereby controlling the flame temperature to reduce nitrogen oxide (NOx) emissions and improve the outlet temperature distribution.

[0056] Through in-depth research, the inventors of this application discovered that during the injection of fuel in the main combustion stage, fuel is typically injected from multiple locations to maximize the uniformity of fuel distribution before combustion, thereby improving combustion efficiency and reducing emissions. However, after injection, the fuel's trajectory is influenced not only by its own momentum but also by the airflow in the main combustion stage. The aerodynamic design of the main combustion stage significantly affects the fuel's trajectory and distribution. If the fuel's trajectory can be altered through aerodynamic design, thereby increasing the fuel distribution area, engine performance can be further improved and pollutant emissions reduced.

[0057] Therefore, based on the above considerations, the inventors, after in-depth research, designed a mixer assembly in this invention. By setting a turbulence generating structure upstream of the fuel nozzle, the velocity of the boundary layer airflow downstream of the turbulence generating structure is reduced and the turbulence intensity is increased. A low-speed, high-turbulence airflow zone is formed downstream of the turbulence generating structure. The airflow in this low-speed, high-turbulence zone can affect the trajectory of the fuel ejected from the fuel nozzle, making the injected fuel have stronger penetrating power and promoting mixing with air. At the same time, it can also cause the fuel to move towards the wall of the annular channel, thereby increasing the fuel distribution area downstream of the main combustion mixer. This achieves the effects of reducing fuel enrichment, reducing fuel combustion temperature, improving combustion efficiency, and reducing pollutant emissions.

[0058] Although the mixer assembly disclosed in the embodiments of this application is applicable to gas turbine engines to achieve the effect of expanding fuel distribution, it is not limited thereto. As long as the engine is designed to expand fuel distribution and reduce pollution emissions, the mixer assembly disclosed in the embodiments of this application can be used.

[0059] In the following description, "fuel" refers to aviation fuel, i.e., aviation kerosene, but it is not limited to this. Any fuel that needs to be atomized can be used with the mixer assembly described in the embodiments.

[0060] refer to Figure 1 , Figure 2 , Figure 13 As shown, in one embodiment, the mixer assembly 100 for a gas turbine engine 1000 may specifically include a main combustion mixer 1001. The main combustion mixer 1001 includes an annular channel 1, fuel injection holes 2, and a turbulence generating structure 3. The annular channel 1 includes an inlet end 101 and an outlet end 102. The inlet end 101 is used to enter air A, and the outlet end 102 is used to discharge a mixture of fuel b and air A. The annular channel 1 also includes a first inner wall surface 103 and a first outer wall surface 104, which together constitute the mixing space of fuel b and air A in the main combustion mixer 1001. Multiple fuel injection holes 2 are circumferentially distributed on the first inner wall surface 103 for injecting fuel b into the annular channel 1. The turbulence generating structure 3 is circumferentially disposed on the first inner wall surface 103, located upstream of the fuel injection holes 2.

[0061] Here, "turbulence-generating structure 3" refers to a structure that can reduce the airflow velocity in the downstream airflow boundary layer, increase turbulence intensity, and create a local "low-velocity zone" or "turbulent zone" between itself and the fuel nozzle. For example... Figure 8B Combination Figure 7B ,exist Figure 8BThe diagram shows the velocity distribution of the swirling airflow a within a radial section θ of the annular channel 1. This radial section θ is located at a fuel nozzle 2. Besides the low-velocity zone 23 formed by the oil mist 20 ejected from the fuel nozzle 2 obstructing the swirling airflow a, there is also a low-velocity zone 24 downstream of the turbulence-generating structure 3. For example... Figure 8A Combination Figure 7A ,exist Figure 8A In the velocity distribution diagram of the swirling airflow a within the radial section θ of the annular channel 1 without a turbulence generating structure, the swirling airflow a is blocked by the oil mist 20' ejected from the fuel nozzle 2, forming a low-velocity zone 23' only downstream of the fuel nozzle 2. The droplets of the oil mist 20' are also mainly distributed in this region. The changes in airflow velocity and turbulence within the low-velocity zone 24 can guide the boundary of the oil mist 20's trajectory to shift towards the wall of the annular channel, thereby increasing the fuel distribution area downstream of the main combustion mixer. The geometric form of the turbulence generating structure 3 includes, but is not limited to, multiple discrete circumferentially distributed bosses, bulges, and pits, or continuous circumferentially distributed slots, steps, and ridges. Its radial cross-sectional shape can also be of various forms, such as triangles and squares.

[0062] The phrase "fuel nozzles inject fuel into the annular channel" means that the orientation of the fuel nozzles is generally radial. In some embodiments, to obtain a better mixing effect of fuel gas, the injection angle of the fuel nozzles is perpendicular to the incoming flow direction.

[0063] The beneficial effect of this embodiment is that by setting a turbulence generating structure upstream of the fuel injection hole, the velocity of the boundary layer airflow downstream of the turbulence generating structure is reduced and the turbulence intensity is increased. A low-speed, high-turbulence airflow zone is formed downstream of the turbulence generating structure. The airflow in this low-speed, high-turbulence zone can affect the trajectory of the fuel ejected from the fuel injection hole, making the injected fuel have stronger penetrating power and promoting mixing with air. At the same time, it can also cause the fuel to move towards the wall of the annular channel, thereby increasing the fuel distribution area downstream of the main combustion mixer. This achieves the effects of reducing fuel enrichment, reducing fuel combustion temperature, improving combustion efficiency, and reducing pollutant emissions.

[0064] refer to Figure 2 Combination Figure 3B As shown, in some embodiments, the main combustion mixer 1001 may further include swirl vanes 4 arranged circumferentially within the annular channel 1, with the swirl vanes 4 and fuel injection holes 2 distributed alternately. Here, "alternatingly distributed" means that swirl vanes 4 are present between circumferentially adjacent fuel injection holes 2, and conversely, fuel injection holes 2 are present between circumferentially adjacent swirl vanes 4. By setting the swirl vanes, the air A entering from the inlet end of the annular channel forms a swirling airflow a, allowing for better mixing of fuel and air, resulting in more complete combustion.

[0065] refer to Figure 2 , Figure 3B , Figure 9A , Figure 9B As shown, in some embodiments, the turbulence generating structure 3 may specifically include a protrusion 31 extending radially outward from the first inner wall surface 103 and / or a recess 32 extending radially inward from the first inner wall surface 103. That is, in some embodiments, the turbulence generating structure 3 only includes the protrusion 31 extending radially outward, without including the recess 32 extending radially inward; in other embodiments, the turbulence generating structure 3 only includes the recess 32, without including the protrusion 31 structure; in still other embodiments, it includes both the protrusion 31 and the recess 32. The advantage of this configuration is that it facilitates the purposeful adjustment and control of the airflow velocity and turbulence intensity range of the downstream boundary layer of the turbulence generating structure. In addition, compared to a combination of convex and concave parts, a single convex part or a single concave part has a stronger ability to adjust the airflow boundary layer downstream of the turbulence generating structure, resulting in lower airflow velocity and stronger turbulence intensity. The geometry of the turbulence generating structure can be selected according to the actual situation to achieve satisfactory aerodynamic design results.

[0066] refer to Figure 7B Combination Figure 9A , Figure 9B As shown, in some embodiments, the turbulence generating structure 3 may have a radial height h and axial width l of the protrusion 31 or concave portion 32 that are less than or equal to 1 / 5 of the radial height H of the annular channel 1. The advantage of this configuration is that it keeps the turbulence generating structure small, does not affect the main flow of the mixer assembly or the main combustion mixer (such as total pressure loss and velocity distribution), and ensures overall flow performance.

[0067] Continue to refer to Figure 7B Combination Figure 9A , Figure 9B As shown, in some embodiments, the turbulence generating structure 3 may have a specific structure in which the axial distance s between the protrusion 31 or the concave portion 32 and the fuel injection orifice 2 is 5-15 times the diameter d of the fuel injection orifice 2. The advantage of this arrangement is that the distance between the turbulence generating structure and the fuel injection orifice allows for the creation of a suitable "low-speed zone" in between, i.e., a suitable airflow velocity and a suitable turbulence intensity, so as to affect only the trajectory of the injected fuel without affecting the flow performance of the mixer assembly or the main combustion mixer as a whole, such as total pressure loss and velocity distribution.

[0068] refer to Figures 9A to 12DAs shown, in some embodiments, the specific structure of the turbulence generating structure 3 can be such that the protrusion 31 can be a continuous convex strip 311 or a plurality of discrete protrusions 312 distributed circumferentially, and the concave portion 32 can be a continuous groove 321 or a plurality of discrete pits 322 distributed circumferentially. Here, "continuous convex strips or grooves distributed circumferentially" means that the turbulence generating structure is a complete annular structure arranged circumferentially, for example... Figures 9A to 9B , Figures 10A to 10B , Figures 11A to 11B , Figures 12A to 12B The structure shown. Here, "multiple discrete protrusions or depressions distributed circumferentially" means that the turbulence-generating structure consists of individual protrusions or depressions, for example... Figures 9C to 9D , Figures 10C to 10D , Figures 11C to 11D , Figures 12C to 12D As shown, the protrusions 312 or recesses 322 are evenly distributed circumferentially. The advantage of this arrangement is that, compared to a continuous annular structure, multiple discrete individual structures have a stronger ability to adjust the airflow boundary layer downstream of the turbulence-generating structure. This results in lower airflow velocities and stronger turbulence intensity. Different geometric forms of the turbulence-generating structure can be selected according to the actual aerodynamic design requirements of the main combustion mixer to achieve precise adjustment of the airflow boundary layer upstream of the fuel nozzle, thereby obtaining a larger fuel distribution area at the main combustion mixer outlet, improving combustion performance, and reducing pollution emissions.

[0069] In some embodiments, the radial cross-sectional shape of the turbulence-generating structure can have various variations, such as Figures 9A to 9D As shown, the radial cross-sectional shape of the turbulence-generating structure is square; as Figures 10A to 10D As shown, the radial cross-sectional shape of the turbulence-generating structure is trapezoidal; as Figures 11A to 11D As shown, the radial cross-sectional shape of the turbulence-generating structure is triangular; as Figures 12A to 12D As shown, the radial cross-sectional shape of the turbulence-generating structure is arc-shaped. The advantage of this design is that different cross-sectional shapes, such as square, trapezoidal, triangular, and arc-shaped, can be selected based on ease of fabrication or design requirements, allowing for flexible arrangement of the structural form. This also facilitates fine-tuning of the airflow boundary layer upstream of the fuel nozzle. It is understood that the choice of cross-sectional shape is not limited to the above; other shapes, stepped shapes, or combinations thereof are also possible.

[0070] refer to Figure 7B Combination Figure 2As shown, in some embodiments, the specific structure of the main combustion mixer 1001 may be such that a radial section θ of the annular channel 1 is located at a fuel injection hole 2, and the distribution of fuel injected from the fuel injection hole 2 on the radial section θ includes an upper boundary 21 and a lower boundary 22. The upper boundary 21 includes a first inflection point 201 and a second inflection point 202. The first inflection point 201 is located at the center line m of the fuel injection hole 2. The lower boundary 22 includes a third inflection point 203 and a fourth inflection point 204, such that the lower boundary 22 is close to the first inner wall surface 103.

[0071] Specifically, due to the influence of the turbulence generating structure 3, the contours of both the upper boundary 21 and the lower boundary 22 are not smooth curves. The upper boundary 21, starting from the fuel nozzle 2, has a first inflection point 201 and a second inflection point 202. The first inflection point 201 is almost located on the centerline m of the fuel nozzle 2, but not necessarily strictly on the centerline. This indicates that the turbulence generating structure 3 increases the penetration of fuel 20 near the fuel nozzle 2, enhancing the mixing degree of fuel and air. The lower boundary 22 also has a third inflection point 203 and a fourth inflection point 204. After two sudden bends, the lower boundary 22 is basically close to the first inner wall surface 103, which plays a role in expanding fuel dispersion.

[0072] Compared to Figure 7A As shown, the fuel distribution on the radial section θ of the annular channel without a turbulence generation structure reveals that after fuel 20' is injected from fuel nozzle 2, its trajectory undergoes a smooth turn of nearly 90 degrees under the influence of the swirling airflow a' without the turbulence generation structure. Ultimately, the fuel droplets largely flow with the swirling airflow a'. Both the upper boundary 21' and the lower boundary 22' are smoothly transitioning curves. It is clearly evident that the fuel dispersion area at the outlet of the main combustion mixer without a turbulence generation structure is significantly smaller than that of the main combustion mixer with a turbulence generation structure.

[0073] Furthermore, such as Figure 3B , Figure 4B As shown, the annular channel 1 has a cross-section γ on its downstream side in the axial direction. Fuel 20 ejected from the fuel nozzle 2 forms a dispersion region N of approximately width W on the cross-section γ. Droplets with a diameter greater than 1 micrometer occupy 20.8% of the area of ​​the cross-section γ in the dispersion region N. Compared to... Figure 3A , Figure 4AAs shown, on the cross-section γ of the annular channel 1 without the turbulence generating structure 3, the fuel 20' ejected from the fuel nozzle 2 forms a dispersion region n of approximately width w under the blowing of the swirling airflow a'. Droplets with a diameter greater than 1 micrometer occupy 15.3% of the area of ​​the cross-section γ in the dispersion region n, meaning that the fuel dispersion area increases by approximately 1 / 3 after the turbulence generating structure is installed. Simultaneously, the width W of the dispersion region N with the turbulence generating structure is approximately 1.3 times the width w of the dispersion region n without the structure. Clearly, the turbulence generating structure increases the fuel dispersion area at the main combustion mixer outlet.

[0074] Furthermore, such as Figure 5B , Figure 6B As shown, a rectangular channel 11 is taken circumferentially within the annular channel 1 where the turbulence generating structure is arranged. The rectangular channel 11 contains only one fuel nozzle 2, and a cross-section β is taken axially downstream of the rectangular channel 11. Under the influence of the swirling airflow a passing through the turbulence generating structure 3, fuel 20 forms a dispersion region E on the cross-section β. In the dispersion region E, droplets with a diameter greater than 1 micrometer occupy 66.2% of the entire area of ​​the cross-section β. Compared to... Figure 5A , Figure 6A As shown, on the cross-section β of the rectangular channel 11 without the turbulence generating structure 3, the flow direction of the swirling airflow a' without the turbulence generating structure is perpendicular to the injection direction of the fuel nozzle 2. Fuel 20' flows parallel to the rectangular channel 11 under the influence of the swirling airflow a'. Fuel 20 forms a dispersion region e on the cross-section β, where droplets with a diameter greater than 1 micrometer occupy 43.5% of the entire area of ​​the cross-section β. Clearly, the turbulence generating structure increases the fuel dispersion area at the main combustion mixer outlet.

[0075] The test conditions of the above comparative schemes are consistent with those of the scheme in this application, except that no turbulence generating structure is set up.

[0076] refer to Figure 2 As shown, in some embodiments, the main combustion mixer 1001 may include an annular cavity 5 for fuel b to flow to the fuel injection port 2. The annular channel 1 at least partially surrounds the annular cavity 5. The annular cavity 5 includes a second inner wall surface 501 and a second outer wall surface 502. The second inner wall surface 501 constitutes the inner wall surface of the main combustion mixer 1001, and the second outer wall surface 502 constitutes the first inner wall surface 103. The advantage of this arrangement is that it facilitates the control of fuel delivery.

[0077] Continue to refer to Figure 2As shown, in some embodiments, the main combustion mixer 1001 may have the following specific structure: the radial upstream side of the annular cavity 5 may also include an end cap 503; the main combustion mixer 1001 may also include a fuel pipe 6, which is fluidly connected to the annular cavity 5 through the end cap 503 to supply fuel b to the annular cavity 5. The fuel b in the fuel pipe 6 first enters the end cap 503 and then flows into the cavity formed by the second inner wall surface 501 and the second outer wall surface 502 to supply fuel injection holes 2 for injection into the annular channel 1. The advantage of this arrangement is that the separate arrangement of the end cap from the second inner wall surface and the second outer wall surface facilitates the processing and assembly of the annular cavity and improves structural strength.

[0078] refer to Figure 1 Combination Figure 2 As shown, in some embodiments, the mixer assembly 100 may include a pre-combustion mixer (not shown), which is at least partially surrounded by the main combustion mixer 1001. This configuration enables staged injection mixing of the mixer assembly, allowing only the pre-combustion mixer to operate under low operating conditions, while the main and pre-combustion mixers operate together under medium to high operating conditions, thus achieving efficient combustion.

[0079] refer to Figure 1 As shown, in one embodiment, the combustion chamber 2000 for the gas turbine engine 1000 may specifically include the mixer assembly 100 and the combustion vessel 200 as described above. The downstream end 1002 of the mixer assembly 100 is connected to the combustion vessel 200 to provide a flow of fuel-air mixture to the combustion vessel 200. In a combustion chamber employing the mixer assembly described above, a turbulence-generating structure is arranged upstream of the fuel nozzle in a stable airflow channel. This alters the local airflow velocity and turbulence distribution of the boundary layer on the upstream wall of the fuel nozzle, creating a low-speed, high-turbulence zone. This results in greater local penetration of the fuel injected from the fuel nozzle, promotes mixing with air, and purposefully guides the spatial trajectory of the injected fuel. Consequently, it increases the fuel spatial distribution area downstream of the fuel nozzle, reducing the likelihood of fuel enrichment and excessive emissions.

[0080] In some embodiments, such as Figure 1 , Figure 2 As shown, the combustion chamber 2000 also includes a diffuser 7, an oil cap 8, an outer combustion chamber casing 9, and an inner combustion chamber casing 10. The mixer assembly 100 is located between the outer combustion chamber casing 9 and the inner combustion chamber casing 10. Air enters the mixer assembly 100 after being decelerated and pressurized by the diffuser 7, making it easier to mix fully with the fuel. The oil cap 8 is located in the outer combustion chamber casing 9. The fuel pipe 6 passes through the oil cap 8 from the outer combustion chamber into the combustion chamber, and the oil cap 8 serves a sealing function.

[0081] refer to Figure 1As shown, in one embodiment, the specific structure of the gas turbine engine 1000 may include the combustion chamber 2000 as described above. The gas turbine engine employing the combustion chamber described above can, by optimizing the aerodynamic structure of the annular flow channel of the main combustion mixer and setting turbulence-generating structures on the flow channel wall, finely adjust the airflow boundary layer near the fuel injection hole, thereby affecting the trajectory of the injected fuel. This achieves the purpose of enhancing the penetration of the injected fuel, promoting mixing with air, and increasing the fuel dispersion area at the main combustion mixture outlet. Ultimately, this provides the necessary conditions for reducing fuel combustion temperature, improving combustion performance, and meeting emission performance requirements.

[0082] In one embodiment, the specific steps of a method for atomizing fuel for a gas turbine engine may include: providing a main combustion mixer, wherein the main combustion mixer is configured such that a turbulence generating structure is provided upstream of a fuel injection orifice located on the inner wall of an annular channel of the main combustion mixer; a first airflow enters the annular channel of the main combustion mixer, flows through the turbulence generating structure, reduces the local airflow velocity, increases the turbulence intensity to form a second airflow; fuel is injected into the annular channel through the fuel injection orifice; and the second airflow mixes with the fuel. Continuing on the above, for example... Figures 2 to 12D As shown, air A flows through the swirl blade 4 and becomes swirling airflow a. Swirling airflow a flows through the turbulence generating structure 3 and becomes a second airflow. A low-speed zone 24 is formed downstream of the turbulence generating structure 3. The low-speed zone 24 changes the trajectory of the fuel injected from the fuel nozzle, giving the fuel injected from the fuel nozzle greater local penetration, promoting mixing with air, and purposefully guiding the spatial trajectory of the fuel after injection. This increases the fuel spatial distribution area downstream of the fuel nozzle, improves combustion performance, and reduces pollution emissions.

[0083] In summary, the beneficial effects of the mixer assembly, combustion chamber, gas turbine engine, and fuel atomization method described in the above embodiments include, but are not limited to, one or a combination of the following:

[0084] 1. By setting a turbulence generating structure upstream of the fuel injection orifice, the velocity of the boundary layer airflow downstream of the turbulence generating structure is reduced and the turbulence intensity is increased. A low-speed, high-turbulence airflow zone is formed downstream of the turbulence generating structure. The airflow in this low-speed, high-turbulence zone can affect the trajectory of the fuel ejected from the fuel injection orifice, making the injected fuel have stronger penetration and promoting mixing with air. At the same time, it can also cause the fuel to move towards the wall of the annular channel, thereby increasing the fuel distribution area downstream of the main combustion mixer. This achieves the effects of reducing fuel enrichment, reducing fuel combustion temperature, improving combustion efficiency, and reducing pollutant emissions.

[0085] 2. In a combustion chamber employing the mixer assembly described above, a turbulence generating structure is arranged upstream of the fuel injection orifice in a stable airflow channel. This alters the local airflow velocity and turbulence distribution of the airflow boundary layer on the upstream wall of the fuel injection orifice, creating a low-speed zone and a high-turbulence zone. This allows the fuel injected through the fuel injection orifice to have greater local penetration, promotes mixing with air, and can purposefully guide the spatial trajectory of the fuel after injection. Consequently, it increases the fuel spatial distribution area downstream of the fuel injection orifice, reducing the possibility of fuel enrichment and excessive emissions.

[0086] 3. The gas turbine engine with the combustion chamber described above can optimize the aerodynamic structure of the annular flow channel of the main combustion mixer and set up turbulence generating structures on the flow channel wall to finely adjust the airflow boundary layer near the fuel injection hole, thereby affecting the motion trajectory of the fuel after injection. This achieves the purpose of enhancing the penetration of the injected fuel, promoting mixing with air, and increasing the fuel dispersion area at the main combustion mixture outlet. Ultimately, this provides the necessary conditions for reducing fuel combustion temperature, improving combustion performance, and meeting emission performance requirements.

[0087] 4. The fuel atomization method of this application can enable the fuel injected from the fuel nozzle to have greater local penetration, promote mixing with air, and purposefully guide the spatial trajectory of the fuel after injection, thereby increasing the fuel spatial distribution area in the downstream region of the fuel nozzle, improving combustion performance, and reducing pollution emissions.

[0088] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A mixer assembly for a gas turbine engine, characterized by, The main combustion mixer comprises: a ring-shaped passage comprising an inlet end for incoming air and an outlet end for discharging a mixture of fuel and air, the ring-shaped passage further comprising a first inner wall surface and a first outer wall surface, the first inner wall surface and the first outer wall surface together constituting a fuel and air mixing space of the main combustion mixer; a plurality of fuel injection holes circumferentially distributed on the first inner wall surface for injecting fuel oil mist into the ring-shaped passage; a turbulence generating structure circumferentially arranged on the first inner wall surface on an upstream side of the fuel injection holes, the turbulence generating structure being arranged adjacent to the fuel injection holes; for fuel injection holes injecting fuel oil mist into the ring-shaped passage, a low speed zone is formed downstream of the turbulence generating structure, and the airflow and turbulence variation of the low speed zone can guide the boundary of the oil mist trajectory to deviate from the wall surface of the ring-shaped passage.

2. The mixer assembly of claim 1, wherein, The main combustion mixer further comprises swirl vanes circumferentially arranged in the ring-shaped passage, the swirl vanes being staggered with the fuel injection holes.

3. The mixer assembly of claim 1, wherein, The turbulence generating structure comprises a protrusion protruding radially outward from the first inner wall surface and / or comprises a recess protruding radially inward from the first inner wall surface.

4. The mixer assembly of claim 3, wherein, The height of the protrusion or the recess in the radial direction and the width of the protrusion or the recess in the axial direction are less than or equal to 1 / 5 of the height of the ring-shaped passage in the radial direction.

5. The mixer assembly of claim 4, wherein, The distance between the protrusion or the recess in the axial direction and the fuel injection holes is 5-15 times the diameter of the fuel injection holes.

6. The mixer assembly of claim 3, wherein, The protrusion can be a continuous protruding strip or a plurality of discrete protrusions circumferentially distributed, and the recess can be a continuous recess or a plurality of discrete recesses circumferentially distributed.

7. The mixer assembly of claim 1, wherein, A radial cross section of the ring-shaped passage is located at one of the fuel injection holes, and the distribution of fuel injected by the fuel injection hole on the radial cross section comprises an upper boundary and a lower boundary, the upper boundary comprises a first inflection point and a second inflection point, the first inflection point is located on the same center line as the fuel injection hole, and the lower boundary comprises a third inflection point and a fourth inflection point, so that the lower boundary is close to the first inner wall surface.

8. The mixer assembly of claim 1, wherein, The main combustion mixer further comprises a ring-shaped cavity for fuel flow to the fuel injection holes, the ring-shaped passage at least partially surrounds the ring-shaped cavity, and the ring-shaped cavity comprises a second inner wall surface and a second outer wall surface, the second inner wall surface constitutes an inner wall surface of the main combustion mixer, and the second outer wall surface constitutes the first inner wall surface.

9. The mixer assembly of claim 8, wherein, The radially upstream side of the ring-shaped cavity further comprises an end cover, and the main combustion mixer further comprises a fuel pipe in fluid connection with the ring-shaped cavity through the end cover to deliver fuel to the ring-shaped cavity.

10. The mixer assembly of claim 1, wherein, The mixer assembly further comprises a pre-combustion mixer at least partially surrounded by the main combustion mixer.

11. A combustor for a gas turbine engine characterized by, The mixer assembly according to any one of claims 1-10; a combustion vessel; wherein the downstream end of the mixer assembly is in communication with the combustion vessel to provide a flow of a mixture of fuel and air to the combustion vessel. The combustion chamber according to claim 11.

12. A gas turbine engine characterized by, ​ 13. A method for atomizing fuel for a gas turbine engine using a mixer assembly according to any one of claims 1-10, the method comprising: providing a main fuel mixer configured to: provide a turbulence generating structure disposed upstream of a fuel injection orifice located in an inner wall surface of an annular passage of the main fuel mixer, a first gas stream entering the annular passage of the main fuel mixer, flowing through the turbulence generating structure, reducing local gas stream velocity, increasing turbulence intensity to form a second gas stream, the fuel injection orifice injecting fuel into the annular passage, the second gas stream mixing with the fuel.

14. A method for atomizing fuel for a gas turbine engine using a mixer assembly according to any one of claims 1-10, the method comprising: providing a main fuel mixer configured to: provide a turbulence generating structure disposed upstream of a fuel injection orifice located in an inner wall surface of an annular passage of the main fuel mixer, a first gas stream entering the annular passage of the main fuel mixer, flowing through the turbulence generating structure, reducing local gas stream velocity, increasing turbulence intensity to form a second gas stream, the fuel injection orifice injecting fuel into the annular passage, the second gas stream mixing with the fuel.

15. A method for atomizing fuel for a gas turbine engine using a mixer assembly according to any one of claims 1-10, the method comprising: providing a main fuel mixer configured to: provide a turbulence generating structure disposed upstream of a fuel injection orifice located in an inner wall surface of an annular passage of the main fuel mixer, a first gas stream entering the annular passage of

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