Fuel staged single swirl nozzle and single tube combustion chamber structure

Abstract

The present invention discloses a fuel-graded single swirl nozzle and a single-tube combustion chamber structure. The fuel-graded single swirl nozzle comprises a nozzle body, a blow-off pipe, an outer wall of a direct-mixed fuel channel and a swirler. The nozzle body is sequentially arranged with a blow-off air channel, a direct-mixed fuel channel and a premixed fuel annular cavity from inside to outside in the radial direction. The nozzle body is sequentially arranged with interconnected swirl channels and premixed channels in the axial direction. The blow-off air channel is located on the inner wall of the blow-off pipe, the direct-mixed fuel channel is located between the outer wall of the direct-mixed fuel channel and the outer wall of the blow-off pipe, the premixed fuel annular cavity is located between the inner wall of the swirler and the outer wall of the direct-mixed fuel channel, the swirl channel is located between the inner wall of the swirler and the outer wall of the swirler, and the swirler has swirl blades in it, the swirl blades are hollow blades, and the swirl blades are provided with premixed fuel spray holes. The fuel-graded single swirl nozzle provided by the present invention has the advantages of strong flame stabilization ability and low pollutant emissions.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbines, and in particular to a fuel-graded single swirl nozzle and a single-tube combustion chamber structure. Background Art

[0002] As environmental protection regulations become increasingly stringent, civil aviation engines and ground-based gas turbines are moving towards low emissions. Especially for ground-based gas turbines, NO emissions must be met within 50% to 100% of the load. X and CO emission requirements. Therefore, it is necessary to adopt advanced combustion organization methods. In order to effectively reduce nitrogen oxide emissions, the combustion organization methods commonly used in gas turbine combustion chambers in related technologies are as follows: ① Adopting lean combustion mode, by increasing the head air intake to reduce the equivalence ratio of the main combustion zone, so that the combustion temperature of the main combustion zone is reduced, thereby inhibiting the formation of thermal nitrogen oxides; ② Adopting premixed combustion organization mode to eliminate high-temperature hot spots in the main combustion zone and reduce the formation of nitrogen oxides; ③ Adopting weak swirl nozzle scheme, increase the gas flow rate in the main combustion zone, reduce the residence time of high-temperature gas in the combustion chamber, so as to reduce the amount of nitrogen oxides generated. However, there are also some problems at the same time. The use of lean premixing and weak swirl schemes is prone to poor flame stabilization under small working conditions and oscillating combustion under large working conditions. The use of lean direct mixing combustion scheme has strong flame stabilization ability, but the pollutant emission level is poorer than lean premixing. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to some extent. To this end, an embodiment of the present invention provides a fuel-graded single swirl nozzle, which has the advantages of strong flame stabilization capability and low pollutant emissions.

[0004] According to the fuel-graded single swirl nozzle of an embodiment of the present invention, the fuel-graded single swirl nozzle includes a nozzle body, a blow-off pipe, an outer wall of a direct-mixed fuel channel and a swirler, wherein the nozzle body is arranged with a blow-off air channel, a direct-mixed fuel channel and a premixed fuel annular cavity in sequence from the inside to the outside in the radial direction, and the nozzle body is arranged with a swirl channel and a premixed channel in sequence in the axial direction, the blow-off air channel is located on the inner wall of the blow-off pipe, the direct-mixed fuel channel is located between the outer wall of the direct-mixed fuel channel and the outer wall of the blow-off pipe, the swirl channel is located between the inner wall of the swirler and the outer wall of the swirler, the swirler has swirl blades therein, the swirl blades are hollow blades, the premixed fuel annular cavity is located between the inner wall of the swirler and the outer wall of the direct-mixed fuel channel, and the premixed fuel annular cavity is connected to the premixed fuel spray hole on the swirl blade.

[0005] In some embodiments, the premix fuel injection hole is located on the windward surface of the swirl blade, and there are multiple premix fuel injection holes.

[0006] In some embodiments, the swirl blades are fixed on the inner wall of the swirler along the circumferential direction, and the blade angle of the swirl blades is 25° to 30°.

[0007] In some embodiments, one end of the blow-off pipe adjacent to the premixing channel is a first injection end, a plurality of air nozzles are evenly distributed on the first injection end, and an end surface of the first injection end is flush with a cross section of the premixing channel outlet.

[0008] In some embodiments, the angle between the axis of the air nozzle hole and the axial direction of the nozzle body is 15° to 45°.

[0009] In some embodiments, the premixing passage is located between an outer wall of the nozzle body and an outer wall of the direct mixing fuel passage.

[0010] In some embodiments, one end of the direct mixing fuel channel adjacent to the premixing channel is a second injection end, the angle between the end face of the second injection end and the axial direction of the nozzle body is 30° to 60°, and the direct mixing fuel spray holes are vertically and evenly distributed on the end face of the second injection end.

[0011] In some embodiments, two groups of tangential air inlet holes are provided on the nozzle body, and the two groups of tangential air inlet holes are staggered in the circumferential direction.

[0012] In some embodiments, the fuel-staged single swirl nozzle is designed with an equivalence ratio of 0.5 to 0.8.

[0013] According to the single-tube combustion chamber structure of an embodiment of the present invention, the single-tube combustion chamber structure includes a flame tube, a nozzle mounting flange and a plurality of single swirl nozzles, the nozzle mounting flange is located at one end of the flame tube, the single swirl nozzle is located on the nozzle mounting flange, and a plurality of flange cooling holes are arranged on the nozzle mounting flange.

[0014] Compared with the related art, the present invention has the following advantages:

[0015] (1) Combining direct-mixing and premixing combustion, the direct-mixing part stabilizes the flame, and the premixing part reduces pollutants, taking into account both flame stability under small working conditions and pollutant emission performance under large working conditions;

[0016] (2) A blow-off pipe is provided at the center of the nozzle. On the one hand, it improves the diffusion and mixing effect of the direct-mixed fuel, effectively improves the combustion efficiency under small working conditions, and reduces the emission of carbon monoxide and unburned hydrocarbons. On the other hand, it can also blow off the unburned mixed gas remaining in the combustion chamber after unsuccessful ignition or flameout, avoiding deflagration during the next ignition.

[0017] (3) In the actual combustion chamber, the present application forms a multi-point lean premixed single-tube combustion chamber solution by reasonably arranging multiple single-swirl fuel grading nozzles and matching reasonable fuel grading methods and fuel supply methods, which can achieve pollutant emissions and outlet temperature distribution within the full operating range to meet the performance requirements of the combustion chamber and turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of a fuel-staged single swirl nozzle according to an embodiment of the present invention.

[0019] Figure 2 4 is a cross-sectional schematic diagram of a fuel-staged single swirl nozzle according to an embodiment of the present invention.

[0020] Figure 3 Schematic diagram of the structure of a single-tube combustion chamber according to an embodiment of the present invention.

[0021] Figure 4 Schematic diagram of nozzle classification of a single-tube combustion chamber structure according to an embodiment of the present invention.

[0022] Figure numerals: 1. Single swirl nozzle; 2. Blow-off pipe; 3. Outer wall of direct-mixed fuel channel; 4. Inner wall of swirler; 5. Swirl blade; 6. Premixed fuel nozzle; 7. Outer wall of swirler; 8. Outer wall of nozzle body; 9. Blow-off air channel; 10. Direct-mixed fuel channel; 11. Premixed fuel annulus; 12. Swirl channel; 13. Blade channel; 14. Premixed channel; 15. Tangential air inlet hole; 16. Direct-mixed fuel nozzle; 17. Air nozzle; 18. First injection end; 19. Second injection end; 20. Nozzle mounting flange; 21. Flange cooling hole; 22. Flame tube; 23. Direct-mixed stage; 24. Main combustion stage one; 25. Main combustion stage two. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0024] The fuel-staged single swirl nozzle 1 according to an embodiment of the present invention is as follows: Figure 1 and Figure 2As shown, the fuel-graded single swirl nozzle 1 includes a nozzle body, a blow-off tube 2, an outer wall 3 of a direct-mixed fuel channel and a swirler. The nozzle body is arranged with a blow-off air channel 9, a direct-mixed fuel channel and a premixed fuel annular cavity 11 in sequence from the inside to the outside in the radial direction. The nozzle body is arranged with a swirl channel 12 and a premixed channel 14 that are connected in sequence in the axial direction. The blow-off air channel 9 is located on the inner wall of the blow-off tube 2, the direct-mixed fuel channel is located between the outer wall 3 of the direct-mixed fuel channel and the outer wall of the blow-off tube 2, the swirl channel 12 is located between the swirler inner wall 4 and the swirler outer wall 7, the swirler has a swirl blade 5, the swirl blade 5 is a hollow blade, a premixed fuel spray hole 6 is provided on the swirl blade 5, the premixed fuel annular cavity is located between the swirler inner wall 4 and the outer wall 3 of the direct-mixed fuel channel, and the premixed fuel annular cavity is connected to the premixed fuel spray hole 6 on the swirl blade. A swirler is installed at one end of the nozzle body, and the other end is connected to the combustion chamber. A swirl channel 12 is set between the swirler inner wall 4 and the swirler outer wall 7. The fuel is supplied in two stages. The direct mixed fuel enters the direct mixed fuel channel 10, is sprayed out through the direct mixed fuel nozzle 16, and is mixed with the swirl air in the combustion chamber while burning, thereby stabilizing the flame. The premixed fuel enters the blade channel 13 of the swirler through the premixed fuel annular cavity 11, and the premixed fuel enters the swirl channel 12 through the premixed fuel nozzle 6 on the swirl blade 5. At this time, the premixed fuel and the swirl air are mixed in the swirl channel 12 and the premixed channel 14, and then enter the combustion chamber for combustion after forming a uniform mixed gas, eliminating the high temperature hot spots in the combustion chamber, thereby reducing the pollutant emissions in the combustion chamber.

[0025] The fuel-graded single swirl nozzle 1 according to the embodiment of the present invention has the advantages of strong flame stabilization ability and low pollutant emissions. The present application combines the two modes of direct mixing and premixed combustion. The direct mixing part stabilizes the flame, and the premixed part reduces pollutants, taking into account both flame stabilization under small working conditions and pollutant emission performance under large working conditions. The setting of the blow-off pipe improves the combustion efficiency under small working conditions and can also blow off the residual gas in the combustion chamber to avoid deflagration.

[0026] In some embodiments, Figure 2 As shown, the premix fuel injection hole 6 is located on the windward side of the swirl blade 5, and there are multiple premix fuel injection holes 6.

[0027] Specifically, the swirl blade 5 is a hollow blade, and a blade channel 13 is arranged inside the hollow blade. The premixed fuel enters the blade channel 13 from the premixed fuel annulus 11 and then enters the premixed channel 14 through the premixed fuel nozzle hole 6. The number of the premixed fuel nozzle holes 6 is 1 to 4, and the aperture is 0.5 to 2 mm.

[0028] In some embodiments, Figure 1 As shown, the swirl blades 5 are fixed on the swirler inner wall 4 along the circumferential direction, and the blade angle of the swirl blades 5 is 25° to 30°.

[0029] Specifically, the swirl blades 5 are hollow straight blades, and the number of the blades is 8 to 16.

[0030] In some embodiments, Figure 2 As shown, one end of the blow-off pipe 2 adjacent to the premixing channel 14 is a first injection end 18 , on which a plurality of air spray holes 17 are evenly distributed, and the end surface of the first injection end 18 is flush with the cross section of the outlet of the premixing channel 14 .

[0031] Specifically, the first injection end 18 of the blow-off pipe 2 is far away from the cyclone, and the end surface of the first injection end 18 is flush with the cross section of the outlet of the premixing channel 14, that is, the end surface of the first injection end 18 is perpendicular to the axial direction of the nozzle body, and the air spray holes 17 are distributed around the first injection end 18, and the axial direction of the air spray holes 17 has a certain angle with the axial direction of the nozzle body. The number of air spray holes 17 is 4 to 12, and the aperture is 2 to 4 mm.

[0032] In some embodiments, Figure 2 As shown, the angle between the axis of the air nozzle hole 17 and the axial direction of the nozzle body is 15° to 45°.

[0033] Specifically, the axis of the air nozzle 17 is in the axial direction of the nozzle body. Figure 2 There is an angle between the horizontal directions in the combustion chamber. When the angle is 15° to 45°, the blowing effect of the blowing pipe on the combustion chamber is most suitable.

[0034] In some embodiments, Figure 2 As shown, the premixing passage 14 is located between the outer wall of the nozzle body and the outer wall 3 of the direct mixing fuel passage.

[0035] Specifically, an annular premixing channel 14 is formed between the outer wall 8 of the nozzle body and the outer wall 3 of the direct mixing fuel channel. The premixing channel 14 is adjacent to the combustion chamber at one end and adjacent to the swirler at the other end in the axial direction of the nozzle body.

[0036] In some embodiments, Figure 2 As shown, one end of the direct mixing fuel channel 10 adjacent to the premixing channel 14 is the second injection end 19 , the angle between the end face of the second injection end 19 and the axial direction of the nozzle body is 30° to 60°, and the direct mixing fuel nozzle holes 16 are vertically and evenly distributed on the end face of the second injection end 19 .

[0037] Specifically, the second injection end 19 is connected to the combustion chamber, and the end face of the second injection end 19 is an inclined end face. The end face of the second injection end 19 is in the axial direction of the nozzle body, that is, Figure 2There is an angle in the horizontal direction, and the angle is most suitable when it is 30° to 60°. The axial direction of the direct mixed fuel injection hole 16 is perpendicular to the inclined end surface, and the direct mixed fuel is sprayed from the direct mixed fuel injection hole 16. The number of the direct mixed fuel injection holes 16 is 4 to 12, and the hole diameter is 1 to 2 mm. The direct mixed fuel channel mainly plays a role in stabilizing the flame. When the load is less than 50%, the direct mixed fuel accounts for 30% to 100% of the total fuel. When the load is higher than 50%, the direct mixed fuel accounts for 10% to 30% of the total fuel.

[0038] In some embodiments, Figure 2 As shown, two groups of tangential air inlet holes 15 are arranged on the outer wall 8 of the nozzle body, and the two groups of tangential air inlet holes 15 are staggered in the circumferential direction.

[0039] Specifically, the tangential air inlet holes 15 are connected to the premixing channel 14, and the tangential air inlet holes 15 can suppress the boundary layer tempering. The aperture of the tangential air inlet holes 15 is 1 to 3 mm. The tangential air inlet holes 15 are divided into two groups, each group includes a plurality of tangential air inlet holes 15 arranged in an array on the outer wall 8 of the nozzle body, and the distance between the tangential air inlet holes 15 and the adjacent tangential air inlet holes 15 is equal. The two groups of tangential air inlet holes 15 are staggered by a certain distance in the circumferential direction and axial direction of the nozzle body to form a cross arrangement.

[0040] In some embodiments, the fuel-staged single swirl nozzle is designed with an equivalence ratio of 0.5 to 0.8.

[0041] According to the single tube combustion chamber structure of the embodiment of the present invention, Figure 3 and Figure 4 As shown, the single-tube combustion chamber structure includes a flame tube 22, a nozzle mounting flange 20 and a plurality of single swirl nozzles 1. The nozzle mounting flange 20 is located at one end of the flame tube 22, and the single swirl nozzle 1 is located on the nozzle mounting flange 20. A plurality of flange cooling holes 21 are arranged on the nozzle mounting flange 20. The aperture of the flange cooling hole 21 is 0.8-2 mm, and the distribution density is 2-4 per square centimeter. The grading method of the plurality of single swirl nozzles 1 in the single-tube combustion chamber directly affects the stability of the combustion chamber operation and the pollutant emission characteristics. The number, arrangement, grading method and fuel supply method of the single swirl nozzles 1 can be changed to meet the requirements of different working conditions. A plurality of single swirl fuel grading nozzles can be reasonably arranged, and a reasonable fuel grading method and fuel supply method can be matched to form a multi-point lean premixed low-emission single-tube combustion chamber solution. Based on this composite grading method, the temperature distribution of the main combustion zone can be uniform within the full range of working conditions, and the pollutant emission and outlet temperature distribution can meet the performance requirements of the combustion chamber and turbine blades.

[0042] Optional, such as Figure 4As shown, there are five single swirl nozzles 1, and the direct mixed fuels in the five single swirl nozzles 1 are used as direct mixed stages 23, sharing a fuel supply system, and the premixed fuel is divided into two stages, two nozzles are main combustion stage 1 24, and the remaining three are main combustion stage 25. The two fuel supply systems independently supply fuel to the nozzles of the main combustion stage 1 24 and the main combustion stage 25. When the combustion chamber working condition is low, only the direct mixed channels of 5 nozzles are connected to natural gas combustion, the direct mixed fuel ratio is 100%, and the equivalence ratio is maintained between 0.7 and 0.8 to maintain flame stability. As the working condition improves, the nozzles of the main combustion stage 1 24 and the main combustion stage 25 enter the working mode in turn, and the direct mixed fuel ratio gradually decreases. Under 100% load, the nozzles of the duty class, the main combustion stage 1 24 and the main combustion stage 25 work at the same time, and the direct mixed fuel ratio is reduced to about 10%. The equivalence ratio of all nozzles is maintained at 0.5 to 0.6, ensuring both stable flame and low pollutant emission level.

[0043] The technical advantages of the single-tube combustion chamber structure according to the embodiment of the present invention are the same as the technical advantages of the above-mentioned fuel-staged single swirl nozzle, which will not be repeated here.

[0044] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0045] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0049] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A fuel-staged single swirl nozzle, characterized in that: include: A nozzle body, wherein the nozzle body is sequentially arranged with a blow-off air channel, a direct-mixing fuel channel and a premixing fuel annular cavity from inside to outside in a radial direction, and the nozzle body is sequentially arranged with a swirl channel and a premixing channel that are connected in an axial direction; A blow-off pipe, wherein the blow-off air passage is located on the inner wall of the blow-off pipe; an outer wall of a direct mixing fuel channel, wherein the direct mixing fuel channel is located between the outer wall of the direct mixing fuel channel and the outer wall of the blow-off pipe; A swirler, wherein the swirl channel is located between the inner wall and the outer wall of the swirler, the swirler has a swirl blade, the swirl blade is a hollow blade, and a premix fuel spray hole is provided on the swirl blade; The premix fuel annular cavity is located between the inner wall of the swirler and the outer wall of the direct-mix fuel channel, and the premix fuel annular cavity is communicated with the premix fuel injection holes on the swirl blades.

2. The fuel-staged single swirl nozzle according to claim 1, characterized in that: The premix fuel injection hole is located on the windward surface of the swirl blade, and there are a plurality of premix fuel injection holes.

3. The fuel-staged single swirl nozzle according to claim 1, characterized in that: The swirl blades are fixed on the inner wall of the swirler along the circumferential direction, and the blade angle of the swirl blades is 25° to 30°.

4. The fuel-staged single swirl nozzle according to claim 1, characterized in that: One end of the blow-off pipe adjacent to the premixing channel is a first injection end, a plurality of air spray holes are evenly distributed on the first injection end, and an end surface of the first injection end is flush with a cross section of the outlet of the premixing channel.

5. The fuel-staged single swirl nozzle according to claim 4, characterized in that: The included angle between the axis of the air spray hole and the axial direction of the nozzle body is 15° to 45°.

6. The fuel-staged single swirl nozzle according to claim 1, characterized in that: The premixing passage is located between an outer wall of the nozzle body and an outer wall of the direct mixing fuel passage.

7. The fuel-staged single swirl nozzle according to claim 1, characterized in that: One end of the direct-mixed fuel channel adjacent to the premixed channel is a second injection end, and the angle between the end face of the second injection end and the axial direction of the nozzle body is 30° to 60°. The direct-mixed fuel spray holes are vertically and evenly distributed on the end face of the second injection end, and the direct-mixed fuel spray holes are used to spray the direct-mixed fuel in the direct-mixed fuel channel.

8. The fuel-staged single swirl nozzle according to claim 1, characterized in that: Two groups of tangential air inlet holes are arranged on the outer wall of the nozzle body, and the two groups of tangential air inlet holes are staggered in the circumferential direction.

9. The fuel-staged single swirl nozzle according to claim 1, characterized in that: The design equivalence ratio is 0.5 to 0.

8.

10. A single-tube combustion chamber structure, characterized in that: It includes a flame tube, a nozzle mounting flange and a plurality of single swirl nozzles, wherein the nozzle mounting flange is located at one end of the flame tube, the single swirl nozzle is located on the nozzle mounting flange, the single swirl nozzle is a fuel-graded single swirl nozzle as described in any one of claims 1 to 9, and a plurality of flange cooling holes are arranged on the nozzle mounting flange.

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