An acoustic suppression axial staging soft combustion nozzle based on vortex shedding dissipation

Abstract

The application provides an acoustic suppression axial staged soft combustion nozzle based on vortex shedding dissipation, which comprises a gas cavity outer wall, a fuel cavity outer wall and a gas film hole. By arranging the axial staged nozzle, the high-temperature flue gas generated by the head burner forms pulsating shedding vortexes after flowing around the nozzle, which can interact with the acoustic field of the combustion chamber, so that the acoustic energy is converted into vortex motion and finally dissipated into fluid internal energy, thereby achieving the effect of suppressing the thermoacoustic oscillation. Meanwhile, the mixing and combustion of the fuel and air in the gas cavity outer wall with the incoming flue gas can effectively avoid the occurrence of backfire and is beneficial to the establishment of soft combustion. The arrangement of multiple rows of fuel holes in the gas cavity and the staggered arrangement of the fuel channels of the adjacent two rows can disperse the reaction zone, thereby reducing the NO X emission. Meanwhile, the arrangement of the ribs in the cavity and the gas film hole of the gas cavity outer wall enhances the durability of the nozzle under high-temperature flue gas conditions. The application can suppress the generation of thermoacoustic oscillation.

Description

Technical Field

[0001] This invention relates to the field of gas turbine combustion chamber technology, and in particular to an acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation. Background Technology

[0002] Heavy-duty gas turbines are core power equipment for efficient energy conversion. With increasingly stringent environmental standards, gas turbine combustion technology is gradually shifting from diffusion combustion to lean premixed combustion. Lean premixed combustion technology reduces peak flame temperature and significantly decreases thermal NOx emissions. X However, this approach introduces the problem of thermoacoustic coupling, leading to thermoacoustic oscillations that can damage critical components of the combustion chamber and downstream turbines. The clean, low-carbon combustion of hydrogen produced from renewable energy sources in heavy-duty gas turbines is also an important component of future energy solutions. However, compared to traditional natural gas, hydrogen's high flame propagation speed and low ignition delay time result in significantly different combustion characteristics and a unique, compact reaction zone morphology, leading to significant variations in the flame's thermoacoustic response. Therefore, to meet the future development requirements of high-parameter and multi-fuel adaptability in gas turbines, it is necessary to achieve low NOx emissions and high combustion stability in the gas turbine combustion chamber through effective combustion organization. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation. Building upon the traditional axially graded combustion organization, it utilizes the coupling between the pulsating shedding vortex formed by the high-temperature flue gas flowing around the nozzle and the acoustic field of the combustion chamber to suppress thermoacoustic oscillations. Simultaneously, by reducing the residence time of high-temperature flue gas and dispersing the reaction zone, it can achieve low emissions of nitrogen oxides.

[0004] This invention utilizes axially staged nozzles. The high-temperature flue gas generated by the head burner flows around the nozzles, forming pulsating shedding vortices that interact with the acoustic field of the combustion chamber. This converts acoustic energy into vortex motion, which is ultimately dissipated as internal fluid energy, thus suppressing thermoacoustic oscillations. Simultaneously, the mixing and combustion organization of fuel and air with the incoming flue gas on the outer wall of the gas chamber effectively prevents backfire and promotes gentle combustion. Multiple rows of fuel holes in the gas chamber, with adjacent rows of staggered fuel channels, disperse the reaction zone, thereby reducing NO₂ levels. X Emissions are reduced. Simultaneously, the internal ribs and the gas film holes on the outer wall of the gas chamber enhance the nozzle's durability under high-temperature flue gas conditions. This invention can reduce nitrogen oxide emissions from the combustion chamber and prevent backfire, while simultaneously suppressing thermoacoustic oscillations by coupling the shedding vortex generated by the surrounding nozzle with the acoustic wave motion.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation includes an outer wall of a gas chamber, an outer wall of a fuel chamber, and gas film orifices. A gas chamber is formed between the outer wall of the gas chamber and the outer wall of the fuel chamber, including a windward section, a lower middle section, an upper middle section, and a leeward section of the gas chamber, separated by multiple partition ribs. The outer wall of the fuel chamber encloses the fuel chamber. The partition ribs connect the outer wall of the gas chamber and the outer wall of the fuel chamber. Inner ribs are located on the outer wall of the gas chamber and the outer wall of the fuel chamber. Injection orifices and gas film orifices are located on the outer wall of the gas chamber. A fuel passage is located on the outer wall of the fuel chamber.

[0007] In this process, after the fuel enters the fuel chamber, it flows through the fuel channel and mixes and burns with the cooling air that enters the gas chamber and is ejected through the jet holes on the outer wall of the gas chamber. The air ejected from the gas film holes located on the outer wall of the gas chamber forms a low-temperature film on the nozzle surface, which separates the nozzle surface from the high-temperature mainstream and cools the nozzle wall, thus playing a dual role of heat insulation and cooling, and preventing the axial stage nozzle from being burned under high-temperature flue gas.

[0008] Preferably, the nozzle has a shape combining an airfoil and a wave-shaped trailing edge. The desired main vortex shedding frequency f is related to the nozzle's structural parameters and the nozzle's angle of attack, satisfying the following conditions. Where St is the Strouhal number, U is the incoming velocity of the high-temperature flue gas, L is the characteristic length of the airfoil, k is an empirical coefficient depending on the airfoil, and α is the angle of attack, defined as the angle between the incoming flow direction and the airfoil chord. In addition, the presence of the lobe trailing edge can induce a multi-source secondary vortex structure, which can interact with the main vortex, widening the vortex shedding frequency range. For a given nozzle structure, in practical use, the desired vortex shedding frequency can be adjusted by changing the nozzle's angle of attack.

[0009] Preferably, the intracavity ribs are located in the windward section of the air cavity, the lower middle part of the air cavity, the upper middle part of the air cavity, and the leeward section of the air cavity.

[0010] Preferably, the air film orifice is located on the outer wall of the air cavity corresponding to the windward section of the air cavity, the lower part of the air cavity, and the top of the nozzle. Cooling air is ejected from the air cavity at a certain angle and momentum, and flows downstream with the incoming airflow.

[0011] Preferably, the fuel passage and the jet orifice are located on the upper part of the gas chamber, the leeward section of the gas chamber, and the outer wall of the fuel chamber corresponding to the top of the nozzle. The high-temperature incoming flue gas, after being mixed with cold air, mixes and burns with the air ejected from the jet orifice and the fuel flowing through the fuel passage outside the outer wall of the gas chamber.

[0012] Preferably, the fuel passages located in the upper part of the air chamber and in the leeward section of the air chamber are arranged in an alternating manner in two adjacent rows.

[0013] Preferably, the thickness w of the jet orifice satisfies 0 < w ≤ 3d, where d is the inner diameter of the fuel passage.

[0014] This invention utilizes an axially staged nozzle design combining an airfoil and a wave-shaped trailing edge to create a pulsating vortex around the incoming high-temperature flue gas. This induces the transfer of acoustic energy in the combustion chamber towards vortex motion, ultimately dissipating it as internal fluid energy, effectively suppressing thermal acoustic phenomena in the combustion chamber. Simultaneously, the mixing and combustion organization of fuel and air with the incoming flue gas on the outer wall of the combustion chamber helps prevent backfire and promotes gentle combustion. Furthermore, the arrangement of multiple rows of fuel holes in the combustion chamber, with adjacent rows staggered, disperses the reaction zone and reduces NO levels. X The emission effect is improved. Meanwhile, the internal ribs and the air film holes on the outer wall of the air chamber effectively prevent the axial staged nozzles from being eroded under the conditions of high-temperature flue gas flow.

[0015] As can be seen from the above technical solution, the acoustic suppression axial graded gentle combustion nozzle based on vortex shedding dissipation of the present invention has the following beneficial effects:

[0016] (1) Compared with the traditional axial stage nozzle, the secondary nozzle of the present invention utilizes the pulsating shedding vortex formed by the flow of high temperature flue gas to interact with the sound field, so that energy is transferred from the sound wave to the vortex wave and finally dissipated into the internal energy of the fluid, which can suppress the generation of thermoacoustic oscillation in the combustion chamber. At the same time, the vortex shedding frequency can be adjusted by the nozzle structure and the angle of attack of the arrangement.

[0017] (2) Compared with the traditional axial staged nozzle, the secondary nozzle of the present invention can avoid the occurrence of backfire by using multiple rows of fuel holes with high efficiency and adopting the organization form of mixing and burning fuel and air with incoming flue gas outside the nozzle. At the same time, it is conducive to the establishment of gentle combustion and further reduces nitrogen oxide emissions.

[0018] (3) Compared with traditional axial grading nozzles, the secondary nozzle of the present invention can cool the wall surface and reduce the risk of axial grading nozzles being burned under high temperature conditions by the flow of air in the air chamber and the setting of air film holes on the outer wall of the air chamber. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to an embodiment of the present invention;

[0020] Figure 2 This is a side cross-sectional view of an acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to an embodiment of the present invention.

[0021] Figure 3The diagram above is a cross-sectional view (AA) of an acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to an embodiment of the present invention.

[0022] The attached diagram is labeled as follows: 1-Air chamber facing section; 2-Lower part of air chamber; 3-Upper part of air chamber; 4-Air chamber leeward section; 5-Fuel chamber; 6-Divider rib; 7-Film gas hole; 8-Outer wall of air chamber; 9-Outer wall of fuel chamber; 10-Inner rib of chamber; 11-Injection hole; 12-Fuel passage; 13-Fuel; 14-Air; 15-Top of nozzle. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0024] like Figures 1-3 As shown, this embodiment of the invention provides an acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation, including an outer wall 8 of the gas chamber, an outer wall 9 of the fuel chamber, and a film gas hole 7. A gas chamber is formed between the outer wall 8 of the gas chamber and the outer wall 9 of the fuel chamber, including a windward section 1, a lower middle section 2, an upper middle section 3, and a leeward section 4 of the gas chamber, which are separated by multiple partition ribs 6. The outer wall 9 of the fuel chamber encloses the fuel chamber 5. The partition ribs 6 connect the outer wall 8 of the gas chamber and the outer wall 9 of the fuel chamber. The inner ribs 10 of the chamber are located on the outer wall 8 of the gas chamber and the outer wall 9 of the fuel chamber. The jet orifice 11 and the film gas hole 7 are located on the outer wall 8 of the gas chamber. The fuel channel 12 is located on the outer wall 9 of the fuel chamber and is inserted into the jet orifice 11, so that the outer wall of the fuel channel 12 and the inner wall of the jet orifice 11 form an annular gap. The fuel channel 12 is set on the outer wall 9 of the fuel chamber and is not connected to the outer wall 8 of the gas chamber.

[0025] like Figure 2 As shown, to avoid backfire, fuel 13 enters the fuel chamber 5 and flows through the fuel channel 12, where it mixes and burns with the cooling air 14 ejected through the jet holes 11 outside the outer wall 8 of the gas chamber. The air ejected from the film gas holes 7 on the outer wall 8 of the gas chamber forms a low-temperature film on the nozzle surface, separating the nozzle surface from the high-temperature mains and cooling the nozzle wall, providing dual protection of heat insulation and cooling, preventing the axial staged nozzle from being ablated by the high-temperature flue gas. The partition ribs 6 have openings, such as... Figure 2 As shown, this is used to prevent thermal stress concentration, allowing air to circulate in the air chamber, enhancing convection, and preventing localized thermal deformation of the nozzle.

[0026] To ensure that the pulsating vortex generated after the incoming high-temperature flue gas flows around the axially staged nozzles interacts with the acoustic field of the combustion chamber, thereby enhancing the damping and dissipation loss of acoustic pulsation energy in the combustion chamber and suppressing thermoacoustic oscillations, the nozzle shape combines an airfoil and a wave-shaped trailing edge. The desired main vortex shedding frequency f is related to the nozzle's structural parameters and the angle of attack of the nozzle arrangement, satisfying... Where St is the Strouhal number, U is the incoming velocity of the high-temperature flue gas, L is the characteristic length of the airfoil, k is an empirical coefficient depending on the airfoil, and α is the angle of attack, defined as the angle between the incoming flow direction and the airfoil chord. Figure 2 In this context, d represents the inner diameter of the fuel passage, and w represents the thickness of the jet orifice.

[0027] In addition, the presence of the lobe trailing edge can induce a multi-source secondary vortex structure, which can interact with the main vortex, broadening the vortex shedding frequency range. For a given nozzle structure, in practical use, the desired vortex shedding frequency can be adjusted by changing the nozzle's angle of attack.

[0028] Preferably, to ensure the axial staged nozzle can operate normally under high-temperature flue gas flow conditions, a combination of internal and external cooling is adopted. To enhance heat exchange between the cooling air 14 and the nozzle's inner surface, the internal ribs 10 are located in the windward section 1, the lower middle section 2, the upper middle section 3, and the leeward section 4 of the air chamber. Since the internal ribs 10 are arranged according to the heat flux density distribution inside the air chamber and do not necessarily have to be on the same plane, therefore... Figure 3 The ribs 10 in the upper part 3 of the air cavity and the leeward section 4 of the air cavity are not shown.

[0029] Preferably, in order to isolate the nozzle surface from the high-temperature flue gas flow and to cool the nozzle surface, the air film orifice 7 is located on the outer wall 8 of the air chamber corresponding to the windward section 1, the lower part 2 of the air chamber, and the top 15 of the nozzle. Cooling air 14 is ejected from the air chamber at a certain angle and momentum, and develops downstream with the incoming flow, forming a low-temperature film on the nozzle surface, which provides dual protection of heat insulation and cooling.

[0030] Preferably, in order to disperse the reaction zone and reduce nitrogen oxide emissions, the fuel channel 12 and the jet orifice 11 are located on the outer walls 9 and 8 of the fuel chamber, corresponding to the upper part 3, the leeward section 4, and the top of the nozzle 15 of the gas chamber. The high-temperature incoming flue gas, after being mixed with cold air, mixes and burns with the cooling air 14 ejected from the jet orifice 11 and the fuel 13 flowing through the fuel channel 12 outside the outer wall 8 of the gas chamber, which is conducive to the establishment of gentle combustion and achieves low nitrogen oxide emissions.

[0031] Preferably, in order to suppress thermoacoustic oscillations, the fuel channels 12 located in the upper part 3 of the air chamber and the leeward section 4 of the air chamber are arranged in an alternating manner in two adjacent rows.

[0032] Preferably, in order to ensure mixing efficiency, the thickness w of the jet hole 11 satisfies 0 < w ≤ 3d, where d is the inner diameter of the fuel channel 12.

[0033] It should be noted that experimental methods not illustrated or described in the accompanying drawings or the main text of the specification are all forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various components above are not limited to the specific structures and shapes mentioned in the embodiments; those skilled in the art can easily modify or substitute them, for example:

[0034] (1) The part where the gas chamber root connects to the fuel chamber does not have to be manufactured as a single piece. The front part of the gas chamber can be connected to the fuel chamber through a connector. The gas chamber can also be accessed from the side, as long as the same function can be performed.

[0035] (2) In the embodiment of the present invention, the cavity rib 10 is a straight rib. In addition, the shape of the cavity rib can also be V-shaped or other forms. The shape, angle and spacing of the ribs need to be designed in combination with the comprehensive cooling effect evaluation of the actual heat transfer characteristics and flow resistance characteristics.

[0036] (3) In the embodiments of the present invention, the air film hole 7 used for cooling the wall surface adopts a traditional cylindrical hole. In addition, air film hole shapes such as scoop-shaped hole, groove-shaped hole, dumbbell-shaped hole, contraction-expansion-shaped hole, funnel-shaped hole, and bidirectional expansion-shaped hole can also be used as substitutes. The shape of the air film hole 7 needs to be designed according to the heat flux density of the nozzle surface so that it can cover the wall surface well.

[0037] (4) The cooling structure used in the embodiments of the present invention is mainly the cavity rib 10 and the air film hole 7. In addition, a composite cooling structure of impact plus air film cooling can also be used, as long as it can effectively cool the nozzle.

[0038] (5) In the embodiment of the present invention, the end face of the fuel channel 12 is flush with the outer wall 8 of the air chamber. In addition, the end face of the fuel channel 12 can be slightly lower than the outer wall 8 of the air chamber, so that the fuel 13 and the air 14 can be premixed in advance.

[0039] (6) Multiple acoustic modes may appear in the actual gas turbine combustor. In this embodiment of the invention, the main mode is the combination of airfoil and lobe trailing edge. It can also be optimized and coupled according to the acoustic modes of the gas turbine combustor. For example, the axial staged nozzle can be designed as a variable cross-section cylinder. As long as the same function can be achieved.

[0040] (7) The present invention may provide examples of parameters containing specific values, but these parameters need not be exactly equal to the corresponding values, but can be approximated within acceptable error tolerances or design constraints;

[0041] (8) The directional terms mentioned in the implementation, such as “front” and “back”, are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of the present invention.

[0042] In summary, this invention utilizes the pulsating shedding vortex formed by the flow of high-temperature flue gas to induce energy transfer from sound waves to vortex waves. The vortex motion, converted from sound wave energy, is then dissipated through viscosity into internal fluid energy, thereby absorbing sound wave energy and suppressing thermoacoustic oscillations. Simultaneously, the arrangement of fuel flowing through the fuel channel and air ejected from the jet holes mixing and burning with the incoming flue gas on the outer wall of the gas chamber effectively prevents backfire under high-temperature flue gas conditions while promoting gentle combustion. By setting multiple rows of fuel holes in the gas chamber, with adjacent rows arranged in an alternating pattern, the reaction zone can be dispersed, reducing NO levels. X The emission effect is improved. Meanwhile, the internal ribs and the air film holes on the outer wall of the air chamber effectively prevent the axial staged nozzles from being eroded under the conditions of high-temperature flue gas flow.

[0043] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. The above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation, characterized in that, It includes an outer wall of the air chamber, an outer wall of the fuel chamber, and film gas holes; an air chamber is formed between the outer wall of the air chamber and the outer wall of the fuel chamber, including an air chamber front section, a lower middle section, an upper middle section, and a leeward section formed by multiple partition ribs; the outer wall of the fuel chamber surrounds the fuel chamber; partition ribs connect the outer wall of the air chamber and the outer wall of the fuel chamber; internal ribs are located on the outer wall of the air chamber and the outer wall of the fuel chamber; jet holes and film gas holes are located on the outer wall of the air chamber; and a fuel passage is located on the outer wall of the fuel chamber. In this process, after the fuel enters the fuel chamber, it flows through the fuel channel and mixes and burns with the cooling air that enters the gas chamber and is ejected through the jet holes on the outer wall of the gas chamber. The air ejected from the gas film holes located on the outer wall of the gas chamber forms a low-temperature film on the nozzle surface, which separates the nozzle surface from the high-temperature mainstream and cools the nozzle wall, thus playing a dual role of heat insulation and cooling, and preventing the axial stage nozzle from being burned under high-temperature flue gas.

2. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 1, characterized in that, The nozzle has a shape combining an airfoil and a wave-shaped trailing edge. The desired main vortex shedding frequency f is related to the nozzle's structural parameters and the nozzle's angle of attack, satisfying the following conditions. Where St is the Strouhal number, U is the incoming velocity of the high-temperature flue gas, L is the characteristic length of the airfoil, k is an empirical coefficient depending on the airfoil, and α is the angle of attack, defined as the angle between the incoming flow direction and the airfoil chord.

3. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 2, characterized in that, The presence of the lobe trailing edge is used to induce a multi-source secondary vortex structure. The secondary vortex and the main vortex interact, broadening the vortex shedding frequency range.

4. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 3, characterized in that, For a given nozzle structure, the desired vortex shedding frequency is adjusted by changing the nozzle's angle of attack.

5. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 1, characterized in that, The internal ribs are located in the windward section, the lower middle part, the upper middle part, and the leeward section of the air cavity.

6. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 1, characterized in that, The air film holes are located on the outer wall of the air cavity corresponding to the windward section of the air cavity, the lower part of the air cavity, and the top of the nozzle; cooling air is ejected from the air cavity at a certain angle and momentum, and flows downstream with the incoming flow.

7. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 1, characterized in that, The fuel passage and jet orifice are located on the outer walls of the fuel chamber and the air chamber, respectively, in the upper part of the air chamber, the leeward section of the air chamber, and the top of the nozzle.

8. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 7, characterized in that, The high-temperature flue gas, after being mixed with cold air, mixes and burns with the air ejected from the jet holes and the fuel flowing through the fuel passage outside the gas chamber.

9. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 7, characterized in that, The fuel channels located in the upper part of the air chamber and in the leeward section of the air chamber are arranged in an alternating pattern on two adjacent rows.

10. The acoustically suppressed axially graded gentle combustion nozzle based on vortex shedding dissipation according to claim 1, characterized in that, The thickness w of the jet orifice satisfies 0 < w ≤ 3d, where d is the inner diameter of the fuel passage.

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