Burner nozzle structure for improving fuel distribution characteristic

Abstract

The invention discloses a burner nozzle structure capable of improving the fuel distribution characteristic. A bluff body swirl vane comprises a plurality of swirl single pieces, a swirl channel is formed between every two adjacent swirl single pieces, the swirl single pieces form an incident flow face on the incident flow side, and when fluid impacts the incident flow face, streaming is formed, wide wake flow is generated, and the phenomenon that the fluid falls off along with vortexes is achieved; and the fuel supply system comprises a fuel cavity and a fuel pipe, one end of the fuel cavity is connected with the fuel pipe, the fuel pipe is arranged along the central axis of the combustor shell, and the fuel cavity is provided with a fuel spray hole communicated into the rotational flow channel. The design of the trapezoidal cross section and the incident flow surface of each rotational flow single piece is utilized to enable fluid to form streaming, wake flow and vortex shedding, turbulent mixing and high-temperature flue gas backflow are enhanced, meanwhile, accurate fuel distribution is achieved through the fuel cavities, the fuel pipes and the fuel spray holes in one-to-one correspondence with the rotational flow channels, combustion-supporting air distribution is further optimized through the multi-stage radial flow dividing rings in the rotational flow channels, and the combustion-supporting effect is improved. And the mixing uniformity of the fuel and the combustion-supporting air is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of burners, and in particular to a burner nozzle structure for improving fuel distribution characteristics. Background Art

[0002] In the structural design of a burner nozzle, the central fuel pipe and fuel chamber are key components for fuel delivery and distribution. Their performance is directly related to the mixing effect of the fuel and combustion-supporting air, which in turn affects combustion efficiency, flame stability, and pollutant emissions. In existing technologies, the central fuel pipe of a burner typically adopts a hollow tube structure design. Its front end connects to the fuel chamber within the swirl blades, and its rear end is connected to the external fuel supply system through an inlet connector. The fuel chamber serves as a transition space, allowing the fuel to slow down after entering the swirl blades, then flow into the fuel channels of each swirl blade, and finally be ejected through the fuel nozzle holes on the blades to mix with the combustion-supporting air.

[0003] However, the existing structure has significant shortcomings in practical applications. First, the connection between the central fuel pipe and the fuel cavity is relatively simple. When fuel enters the fuel cavity directly from the central fuel pipe, it is prone to localized impact due to uneven flow velocity distribution within the pipe, resulting in unstable fuel flow within the fuel cavity and difficulty in evenly distributing the fuel to the fuel channels of each swirl blade. Second, the fuel cavity lacks targeted flow guidance or buffering structures. When the pressure and flow rate of the external fuel supply fluctuate, the fuel distribution within the cavity is prone to deviation, resulting in inconsistent fuel amounts in the fuel channels of different swirl blades.

[0004] The root cause of these problems lies in the inadequate consideration of the flow characteristics of fuel during transportation and distribution in existing designs. Flow velocity is reduced solely by expanding the volume of the fuel chamber, without effectively regulating the flow field of the fuel entering the chamber, or implementing a balancing mechanism for multi-channel distribution scenarios. This results in poor fuel distribution uniformity across channels. Consequently, the mixing of fuel and combustion-supporting air is poor, leading to incomplete combustion in some areas due to excessively concentrated fuel, increasing pollutant emissions. In other areas, excessively lean fuel leads to reduced flame stability and even combustion interruption. This can also cause localized overheating of the burner, shortening the equipment's service life.

[0005] In view of the above reasons, it is necessary to propose a burner nozzle structure with improved fuel distribution characteristics to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects in the prior art and provide a burner nozzle structure with improved fuel distribution characteristics.

[0007] To achieve the above object, the technical solution of the present invention is as follows: A burner nozzle structure for improving fuel distribution characteristics includes a burner housing: a cylindrical pipe with two ends open, one end of which is an inlet end for combustion air and the other end is a combustion end for spraying mixed materials; The swirler structure includes a blunt-body swirl blade disposed within the combustion end. The blunt-body swirl blade comprises a plurality of swirl blades arranged symmetrically about the axis of the burner housing. A swirl channel is formed between two adjacent swirl blades. The cross-section of the swirl blades is trapezoidal, and the width of the swirl blades gradually increases radially from the inside to the outside. The swirl blades form a frontal surface perpendicular to the direction of fluid flow on at least the frontal side. When the fluid strikes the frontal surface, a circumferential flow is formed, resulting in boundary layer separation and a wide wake, accompanied by vortex shedding. Fuel supply system: It includes a fuel chamber and a fuel pipe. The fuel chamber is arranged at the center of the blunt body swirl blade. The fuel chamber is hollow inside. One end of the fuel chamber is connected to the fuel pipe. The fuel pipe is arranged along the central axis of the burner shell. The fuel chamber is provided with a fuel nozzle connected to the swirl channel.

[0008] Furthermore, two adjacent swirl monoliths are arranged parallel to each other with their end faces close to one side, and multiple partition plates are radially provided in the swirl channel. The partition plates divide the swirl channel into multiple partition channels, and each partition channel is provided with at least one fuel nozzle. Several partition plates arranged circumferentially form multi-stage radial diversion rings with different radii.

[0009] Furthermore, the fuel supply system also includes a fuel radial tube, which is formed inside the swirl monolith and arranged radially. One end of the fuel radial tube is connected to the fuel cavity. The setting position of the fuel radial tube corresponds to the swirl channel. The fuel radial tube is provided with a fuel spray hole in a direction perpendicular to the swirl monolith toward the swirl channel.

[0010] Furthermore, the burner shell has a two-section structure including a burner head shell and a straight tube shell. The burner head shell and the straight tube shell are connected by an air inlet flange. A swirler structure and a fuel supply system are arranged inside the burner head shell. A combustion air inlet is provided at the end of the straight tube shell. An outer ring flange for installing an auxiliary structure is also provided on the outside of the burner head shell.

[0011] Furthermore, the fuel pipe includes an axial material pipe and a radial material pipe. One end of the axial material pipe is connected to the radial material pipe, and the two form an L-shaped structure. The axial material pipe is arranged along the axis of the burner shell and the end is connected to the fuel cavity. The radial material pipe passes through the burner shell radially and is provided with an inlet joint.

[0012] Furthermore, the fuel pipe is a three-section stepped pipe including an inlet pressure stabilizing section, a throttling and deceleration section, and a jet distribution section. The inner wall of the inlet pressure stabilizing section is provided with a spiral guide vane; the throttling and deceleration section gradually expands in diameter from the end of the inlet pressure stabilizing section; one end of the jet distribution section is connected to the throttling and deceleration section, and the other end is a blind end placed in the fuel cavity. The jet distribution section is provided with a plurality of inclined jet holes on the circumferential side wall at one end inside the fuel cavity, and the jet holes point to the inner wall of the fuel cavity to form a wall impact jet.

[0013] Furthermore, the fuel chamber includes a central buffer chamber and a radial guide tube. The central buffer chamber is arranged inside the fuel chamber and located at the axis of the burner. The inner wall of the central buffer chamber is covered with a porous foam metal layer. The side wall of the central buffer chamber is connected to a radial guide tube. The number of radial guide tubes corresponds to the number of swirl single pieces. One end of the radial guide tube is connected to the central buffer chamber, and the other end is directly connected to the fuel radial tube.

[0014] Furthermore, an annular drainage cavity is formed between the outer wall of the central buffer cavity and the inner wall of the fuel cavity. The radial guide pipe is provided with a Venturi tube section in the annular drainage cavity. The narrow throat of the Venturi tube section is provided with a drainage hole connected to the annular drainage cavity. The annular drainage cavity is provided with an air inlet on the side facing the inlet end.

[0015] Furthermore, the radial flow guide tube is provided with an elastic flow balancing plate. When the channel resistance of a radial flow guide tube increases, the flow balancing plate automatically deforms to increase the flow area, or when the flow of the radial flow guide tube is too high, the flow balancing plate is compressed and deformed to reduce the flow area.

[0016] Furthermore, the flow balancing plate is a circular thin sheet structure, the edge of which is fixed on the radial guide tube, and the central area is in a free state and deforms with the fuel flow and pressure. A circular mainstream through hole is provided in the center of the flow balancing plate, and a plurality of auxiliary adjustment holes are provided around the mainstream through hole. A flow tube is provided on the auxiliary adjustment hole. One end of the flow tube is fixed on the auxiliary adjustment hole, and the other end is a free end, and the free end is set as an oblique cut. The opening of the oblique cut faces the inner wall of the radial guide tube. When the flow balancing plate is deformed, the free end is controlled to deflect and swing so that the oblique cut fits the inner wall of the radial guide tube to close the auxiliary adjustment hole.

[0017] The advantages and beneficial effects of the present invention are: 1. The present invention adopts a cylindrical segmented burner shell with openings at both ends, combined with blunt-body swirl blades distributed symmetrically around the center, and utilizes the swirl single-piece trapezoidal cross-section and the oncoming surface design to form fluid swirl, wake and vortex shedding, thereby enhancing turbulent mixing and high-temperature flue gas recirculation. At the same time, precise fuel distribution is achieved through the fuel cavity, fuel pipe and fuel nozzles that correspond one-to-one with the swirl channel. The multi-stage radial diverter ring in the swirl channel further optimizes the distribution of combustion-supporting air, effectively improving the mixing uniformity of fuel and combustion-supporting air, enhancing combustion stability and reducing pollution emissions.

[0018] 2. The fuel pipe is improved into a three-section stepped pipe. The spiral guide vanes in the inlet pressure stabilization section, the gradual change of the pipe diameter in the throttling and deceleration section, and the inclined jet holes in the jet distribution section are used to improve the fuel delivery stability and premixing effect. The fuel chamber adopts a central buffer chamber, an annular drainage chamber, and a radial guide tube structure with a Venturi tube section, combined with a porous foam metal layer and a small amount of combustion-supporting air premixing to further optimize the fuel distribution and flow performance. The design of the elastic flow balancing plate realizes the dynamic balance of the flow in each channel, significantly improving the accuracy of fuel distribution and the system's anti-interference ability, making the combustion stability better and further reducing pollutant emissions. It is suitable for scenarios with higher requirements for combustion performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an axonometric diagram of a burner nozzle structure for improving fuel distribution characteristics according to the present invention; Figure 2 yes Figure 1 Schematic diagram of the longitudinal section; Figure 3 It is a schematic diagram of the structure of the blunt body swirl blade and the fuel pipe; Figure 4 This is a schematic diagram of the incident side of the blunt-body swirl blade in the present invention; Figure 5 Schematic cross-sectional view of the flow pattern formed by airflow passing through a swirl sheet in the present invention; Figure 6 It is a schematic structural diagram of the fuel radial tube within the blunt-body swirl blade of the present invention; Figure 7 It is a structural diagram of embodiment 2 of the present invention; Figure 8 This is a schematic structural diagram of Embodiment 3 of the present invention; Figure: 1, burner housing; 2, inlet end; 3, combustion end; 4, blunt-body swirl blade; 5, swirl monolith; 6, swirl channel; 7, front face; 8, wide wake; 9, vortex shedding; 10, fuel cavity; 11, fuel pipe; 12, fuel nozzle hole; 13, partition plate; 14, radial fuel pipe; 15, burner head housing; 16, straight pipe housing; 17, air inlet flange; 18, combustion air inlet; 19, outer flange; 20, axial feed pipe ; 21. Radial material pipe; 22. Inlet joint; 23. Inlet pressure stabilizing section; 24. Throttling and deceleration section; 25. Jet distribution section; 26. Spiral guide vane; 27. Jet hole; 28. Central buffer chamber; 29. ​​Radial guide pipe; 30. Porous foam metal layer; 31. Annular drainage chamber; 32. Venturi tube section; 33. Drainage hole; 34. Air inlet; 35. Flow balancing plate; 36. Circular mainstream through hole; 37. Flow pipe; 38. Bevel cut. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are further described below in conjunction with the examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] Example 1: This embodiment discloses a burner nozzle structure that improves fuel distribution characteristics. By optimizing the flow field characteristics of the blunt-body swirl blades 4 and the precise distribution of fuel supply, the uniformity of mixing fuel and combustion air is improved, thereby enhancing combustion stability and reducing pollutant emissions. The specific structural design is as follows: like Figure 1-6 As shown, it includes a burner shell 1, which is a segmented structure. The burner shell 1 is a cylindrical pipe with two ends open. It adopts a two-stage design to adapt to different functional requirements. It includes a straight tube shell 16: as the introduction section of the combustion air, its end is provided with a combustion air inlet 18 for connecting to the external air supply system. After the combustion air enters the shell along the axial direction, it forms a stable axial airflow through the guiding effect of the inner wall of the pipe. The burner head shell 15: as the core area of ​​the combustion reaction, it is connected to the straight tube shell 16 through the air inlet flange 17. The swirler structure and fuel supply system are integrated inside. The outer ring flange 19 is provided on the outside for installing auxiliary structures to ensure the control of the combustion process.

[0022] The two-stage structure design not only ensures the stable delivery of combustion air, but also provides a compact space for the integration of the cyclone and the fuel system.

[0023] Furthermore, the swirler structure adopts a flow field enhancement design based on blunt-body swirl blades 4. Specifically, the swirler structure is the key to achieving airflow rotation and mixing. Its core is a number of swirl blades 5 distributed symmetrically around the burner axis. The specific design features are as follows: It includes a plurality of swirl sheets 5 (this embodiment takes ten swirl sheets 5 as an example). The cross section of each swirl sheet 5 is trapezoidal, and the width gradually increases from the inside to the outside along the radial direction. This design makes the swirl channel 6 formed between adjacent swirl sheets 5 nearly parallel on both sides, which adapts to the flow rate requirements when the airflow diffuses in the radial direction. At the same time, Figure 5 As shown, the incoming side of the swirl blade 5 forms an incoming surface 7 perpendicular to the direction of fluid flow. When the combustion-supporting air strikes the incoming surface 7, a circumferential flow effect occurs, causing boundary layer separation at the edge of the incoming surface 7, forming a wide wake 8 behind the blade, accompanied by vortex shedding 9. This flow field characteristic, on the one hand, enhances the turbulence intensity of the airflow through vortices, promoting mixing with the fuel. On the other hand, the low-pressure environment in the wake region can draw back high-temperature flue gas, providing a heat source for ignition and stable combustion. Thus, the blunt-body swirl blades 4 achieve the goal of promoting mixing and stable combustion.

[0024] Furthermore, the hierarchical separation structure of the swirl channel 6 is specifically structured as follows: multiple partition plates 13 are radially disposed within the swirl channel 6. These partition plates 13 are circumferentially connected to form multi-stage radial diversion rings of varying radii. Specifically, in this embodiment, four partition plates 13 are provided, forming four rings of radial diversion rings. These four partition plates divide each swirl channel 6 into three independent, separated channels. The multi-stage diversion ring design allows the combustion air to form independent flow beams at different radial locations, avoiding uneven airflow distribution caused by overly wide channels and paving the way for subsequent precise mixing with the fuel.

[0025] Furthermore, precise distribution and directional injection mixing are achieved through the fuel supply system. The fuel supply system realizes uniform mixing of fuel and combustion-supporting air in each separated channel through the coordinated design of the fuel chamber 10, the fuel pipe 11 and the nozzle. The specific structure is as follows: The fuel chamber 10 is a hollow structure located at the center of the blunt-body swirl blades 4. One end of the fuel chamber is connected to the fuel pipe 11, serving as the fuel distribution hub. The fuel pipe 11 adopts an L-shaped structure, consisting of an axial pipe 20 and a radial pipe 21. The axial pipe 20 is arranged along the central axis of the burner housing 1, and its end is connected to the fuel chamber 10, ensuring stable fuel delivery along the axis to the central area. The radial pipe 21 extends radially out of the burner housing 1 and is equipped with an inlet connector 22 at its end for connection to an external fuel supply system. The L-shaped structure not only adapts to the spatial layout of the housing, but also reduces the fuel flow rate through pipe bends, avoiding distribution deviations caused by excessive flow rate.

[0026] Directed fuel injection occurs through fuel injection holes 12. A radial fuel tube 14 is radially arranged within the swirl plate 5. One end connects to the fuel chamber 10, while the other end faces the swirl channel 6, corresponding to each of the separate channels. Fuel injection holes 12 are positioned perpendicular to the surface of the swirl plate 5, ensuring that fuel is injected into the combustion-supporting air within the separate channels at a vertical angle. Each separate channel has at least one fuel injection hole 12, and the number of injection holes corresponds to the number of separate channels. In this embodiment, one fuel injection hole 12 is provided in each separate channel. This ensures point-to-point fuel injection within each independent airflow stream, minimizing mixing dead zones and allowing direct injection from the fuel injection holes 12 to more evenly mix with the air within the swirl channel 6, forming a homogeneous mixture. Furthermore, the vertical injection design reduces the risk of fuel backflow into the fuel tube 11, minimizing the risk of flashback. Furthermore, the vertical injection is perpendicular to the gas flow within the separate channels, promoting vertical mixing.

[0027] In this embodiment, after the combustion-supporting air enters through the straight tube housing 16, it is distributed to each separated channel through a multi-stage radial diversion ring, forming a uniform radial airflow beam; the fuel is transported to the central fuel cavity 10 through the L-shaped fuel pipe 11, and then injected into the corresponding separated channel through the fuel radial pipe 14 and the directional nozzle hole, and is mixed with the combustion-supporting air in each independent channel. At the same time, the frontal surface 7 of the swirl monolith 5 generates vortexes and vortices, strengthening turbulent mixing, and the recirculating flue gas in the wake zone further promotes combustion stability. This structure enables the fuel and combustion-supporting air to be precisely proportioned and fully mixed in different radial regions, ultimately forming a uniform and stable mixture at the combustion end 3, effectively improving combustion stability and reducing pollution.

[0028] Example 2: This embodiment, based on the first embodiment, optimizes the flow stability and distribution uniformity of the fuel supply system. By designing a three-stage stepped fuel pipe 11, a graded buffer fuel cavity 10, and an elastic flow balancing sheet 35, the mixing accuracy of the fuel and combustion-supporting air is further improved. This embodiment is suitable for scenarios requiring higher combustion stability. The specific structure and working process are as follows: In this embodiment, Figure 7 As shown, the fuel pipe 11 adopts a three-stage stepped structure, replacing the L-shaped straight pipe in the first embodiment, and realizes stable and uniform fuel delivery by optimizing the flow field characteristics step by step.

[0029] Specifically, the inlet pressure-stabilizing section 23, serving as the initial fuel entry point, has spiral guide vanes 26 welded to its inner wall. For example, the lead is twice the pipe diameter, e.g., 100 mm for a 50 mm pipe diameter. When fuel (e.g., natural gas) flows through the inlet connector 22, the spiral guide vanes 26 force the fuel to generate a weak swirl (swirl number S = 0.2) along the pipe wall. This eliminates turbulent unevenness caused by pipe elbows and valve disturbances, creating an axisymmetric flow field before the fuel enters the next stage. For example, if a small amount of impurities are mixed into the fuel or if localized flow velocity deviations occur due to supply pressure fluctuations, the rotational rectification effect of the spiral guide vanes 26 can control the flow velocity fluctuations to within ±5%, paving the way for subsequent distribution.

[0030] The throttling and deceleration section 24 is connected to the end of the inlet pressure stabilizing section 23. In this embodiment, the tube diameter gradually expands from 50 mm to 80 mm along the axial direction, with a taper angle of 15°. According to the Bernoulli principle in fluid mechanics, the expansion of the cross section can reduce the fuel flow rate, converting kinetic energy into static pressure energy, and avoiding local disturbances caused by the high-speed fluid directly impacting the fuel chamber 10. Taking liquefied petroleum gas as an example, it has a low viscosity and is easy to vaporize. It is easy to produce "jet segregation" when flowing at high speed. The throttling and deceleration section 24 can form a stable static pressure field for the fuel before entering the jet distribution section 25 by reducing the flow rate, ensuring that the injection pressure of each jet hole 27 is consistent.

[0031] The jet distribution section 25: one end is connected to the throttling deceleration section 24, and the other end is a blind end, and the whole is placed inside the fuel chamber 10. Its circumferential side wall is evenly provided with a plurality of inclined jet holes 27 along the radial direction. The inclined jet holes 27 are at an angle of 30° to the axis, with an aperture of 8mm, and the outlet of the jet hole 27 points to the inner wall of the fuel chamber 10. After being decelerated, the fuel passes through the jet hole 27 to form a high-speed jet with a flow rate of 8m / s. After hitting the inner wall of the fuel chamber 10, it rebounds to form a ring flow, so that the fuel is pre-mixed in the chamber. For example, when the fuel is a mixed gas, such as natural gas and propane mixed in a ratio of 3:1, the turbulent mixing generated by the wall impact jet can eliminate component stratification, so that the deviation of the fuel component entering the subsequent channel is less than 3%.

[0032] In this embodiment, the central buffer chamber 28 is located at the burner axis. Its inner wall is coated with a porous metal foam layer 30 with a porosity of 90%, made of a high-temperature resistant nickel-based alloy. Fuel injected through the jet distribution section 25 first enters the central buffer chamber 28. The labyrinthine structure of the porous metal foam further eliminates turbulent disturbances while simultaneously creating a uniform pressure field within the chamber through its capillary action. For example, when the inlet pressure of the fuel pipe 11 experiences a short-term fluctuation, such as a sudden increase from 0.3 MPa to 0.35 MPa, the damping effect of the metal foam can reduce the pressure fluctuation within the chamber to ±2%, thus preventing sudden changes in flow.

[0033] Annular diversion chamber 31 and Venturi tube section 32: An annular space, or annular diversion chamber 31, is formed between the outer wall of the central buffer chamber 28 and the inner wall of the fuel chamber 10. An air inlet 34 is provided on the side 2 facing the combustion air inlet 18, which allows for the introduction of a small amount of combustion air, approximately 5% of the total air volume. The radial diversion tubes 29, whose number matches the swirl monolith 5, connect one end to the central buffer chamber 28 and the other end through the annular diversion chamber 31 and faces the radial fuel tube 14 within the swirl monolith 5. The section within the annular diversion chamber 31 is machined into a Venturi tube section 32 with a contraction ratio of 0.6. When the fuel flows through the narrow throat of the Venturi, the flow rate reaches up to 12 m / s. Due to the Venturi effect, the static pressure at the narrow throat decreases, and the combustion air within the annular diversion chamber 31 is drawn in through the diversion holes 33, forming a premixed flow of fuel and a small amount of air. The early mixing of a small amount of air reduces fuel viscosity and prevents coking and clogging within the radial diversion tubes 29.

[0034] After being premixed in the Venturi section 32, the fuel is precisely directed into the fuel radial tubes 14 within the swirl monolith 5 via radial guide tubes 29. Because the guide tubes correspond one-to-one with the fuel radial tubes 14 and their axes are coaxial, the fuel can flow into the subsequent channels in a straight line, avoiding flow losses caused by path bends.

[0035] Example 3: In this embodiment, an elastic flow balancing plate 35 is added to the radial flow guide tube 29 near the outlet of the fuel radial tube 14. Through passive deformation, the dynamic balance of the flow in each channel is achieved, forming a flow compensation mechanism with dynamic feedback regulation. Its structure and working process are as follows: Specifically, such as Figure 8 As shown, the flow balancing plate 35 is a Hastelloy thin sheet with a thickness of 0.1-0.3mm and a circular diameter of 15mm. Its edges are fixed to the inner wall of the radial flow guide tube 29 via slots, while the center area is free. A φ5mm main flow hole is provided in the center, surrounded by four φ2mm auxiliary adjustment holes. Each auxiliary adjustment hole is welded to a flow tube 37 of a certain length. The free end of the flow tube 37 has an oblique cutout 38, with the opening of the cutout 38 facing the inner wall of the flow guide tube.

[0036] The dynamic adjustment process is as follows: when the flow rate of a radial flow guide tube 29 is low due to increased local resistance (such as slight blockage of the fuel radial tube 14), the pressure in the tube decreases, and the balancing plate contracts toward the center under its own elastic action, such as Figure 8 -A, at this time, the flow balancing piece 35 is flat, the main flow hole area remains unchanged, and the free end of the flow tube 37 is far away from the tube wall, so that the auxiliary regulating hole is fully opened, the total flow area increases by 15%, compensating for the flow loss; when the flow of a certain channel is too high (such as a sudden increase in inlet pressure), as shown in FIG. Figure 8As shown in Figure 2-B, as the pressure within the pipe increases, the center of the flow balancing plate 35 bulges toward the outlet, causing the free end of the flow tube 37 to swing and sway against the wall of the radial flow guide 29. This causes the beveled cutout 38 to close the auxiliary regulating hole, leaving only the main flow hole for flow, reducing the flow area and suppressing excessive flow. For example, if the flow in a particular channel suddenly increases by 20%, the balancing plate can complete its deformation adjustment within 0.1 seconds, controlling the flow deviation to within ±3%.

[0037] Taking the application of natural gas in an industrial kiln as an example, the working process of this embodiment is as follows: natural gas enters the three-section fuel pipe 11 through the inlet connector 22. The spiral guide vane 26 of the inlet pressure-stabilizing section 23 eliminates turbulence, the throttling and deceleration section 24 reduces the flow rate to 5 m / s, and the jet distribution section 25 injects the fuel into the central buffer chamber 28 through the inclined jet hole 27. After being stabilized by the porous foam metal, it enters the radial guide tube 29. At the same time, a small amount of combustion-supporting air is introduced into the annular guide chamber 31, which is premixed with the fuel in the Venturi section 32 to reduce flow resistance. When the fuel flows through the radial guide tube 29, the flow equalizer 35 dynamically adjusts the flow area according to the real-time flow rate to ensure that the fuel distribution deviation of each swirl single piece 5 is ≤3%. Finally, the fuel is injected into the swirl channel 6 through the nozzle of the fuel radial tube 14, and is fully mixed with the combustion-supporting air in the multi-stage separation channel. After being strengthened by the flow and vortex of the blunt-body swirl blades 4, a stable combustion mixture is formed.

[0038] Actual tests show that the combustion stability of this structure is improved by 15% compared with Example 1, and NOx emissions are reduced to below 80mg / m³, making it suitable for industrial combustion scenarios with low pollution and high stability requirements.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A burner nozzle structure for improving fuel distribution characteristics, characterized in that: The burner shell is a cylindrical pipe with two open ends, one end of which is the inlet end for the combustion air and the other end is the combustion end for the mixture to be ejected; The swirler structure includes a blunt-body swirl blade disposed within the combustion end. The blunt-body swirl blade comprises a plurality of swirl blades arranged symmetrically about the axis of the burner housing. A swirl channel is formed between two adjacent swirl blades. The cross-section of the swirl blade is trapezoidal, and the width of the swirl blade gradually increases radially from the inside to the outside. The swirl blade forms a frontal surface perpendicular to the direction of fluid flow on at least the frontal side. When the fluid strikes the frontal surface, a circumferential flow is formed, resulting in boundary layer separation and a wide wake, accompanied by vortex shedding. Fuel supply system: It includes a fuel chamber and a fuel pipe. The fuel chamber is arranged at the center of the blunt body swirl blade. One end of the fuel chamber is connected to the fuel pipe. The fuel pipe is arranged along the central axis of the burner shell. The fuel chamber is provided with a fuel nozzle connected to the swirl channel.

2. A burner nozzle structure for improving fuel distribution characteristics according to claim 1, characterized in that: A plurality of partition plates are radially arranged in the swirl channel, and the partition plates divide the swirl channel into a plurality of partition channels, and each partition channel is provided with at least one fuel injection hole.

3. A burner nozzle structure for improving fuel distribution characteristics according to claim 1 or 2, characterized in that: The fuel supply system also includes a fuel radial tube, which is formed inside the swirl monolith and arranged radially. One end of the fuel radial tube is connected to the fuel cavity. The setting position of the fuel radial tube corresponds to the swirl channel. The fuel radial tube is provided with a fuel spray hole in a direction perpendicular to the swirl monolith toward the swirl channel.

4. The burner nozzle structure for improving fuel distribution characteristics according to claim 1, characterized in that: The burner shell has a two-section structure and includes a burner head shell and a straight tube shell. The burner head shell and the straight tube shell are connected by an air inlet flange. A swirler structure and a fuel supply system are arranged inside the burner head shell. A combustion air inlet is provided at the end of the straight tube shell. An outer ring flange for mounting an auxiliary structure is also provided on the outside of the burner head shell.

5. The burner nozzle structure for improving fuel distribution characteristics according to claim 1, characterized in that: The fuel pipe includes an axial material pipe and a radial material pipe. One end of the axial material pipe is connected to the radial material pipe, and the two form an L-shaped structure. The axial material pipe is arranged along the axis of the burner shell and the end is connected to the fuel cavity. The radial material pipe passes through the burner shell radially and is provided with an inlet joint.

6. The burner nozzle structure for improving fuel distribution characteristics according to claim 1, characterized in that: The fuel pipe is a three-section stepped pipe including an inlet pressure stabilizing section, a throttling and deceleration section, and a jet distribution section. The inner wall of the inlet pressure stabilizing section is provided with a spiral guide vane; the throttling and deceleration section gradually expands in diameter from the end of the inlet pressure stabilizing section; one end of the jet distribution section is connected to the throttling and deceleration section, and the other end is a blind end placed in the fuel cavity. The jet distribution section is provided with a plurality of inclined jet holes on the circumferential side wall at one end inside the fuel cavity, and the jet holes point to the inner wall of the fuel cavity to form a wall impact jet.

7. A burner nozzle structure for improving fuel distribution characteristics according to claim 1 or 6, characterized in that: The fuel chamber includes a central buffer chamber and a radial guide tube. The central buffer chamber is arranged inside the fuel chamber and located at the axis of the burner. The inner wall of the central buffer chamber is covered with a porous foam metal layer. The side wall of the central buffer chamber is connected to a radial guide tube. The number of radial guide tubes corresponds to the number of swirl single sheets. One end of the radial guide tube is connected to the central buffer chamber, and the other end is directly connected to the fuel radial tube.

8. The burner nozzle structure for improving fuel distribution characteristics according to claim 7, characterized in that: An annular drainage cavity is formed between the outer wall of the central buffer cavity and the inner wall of the fuel cavity. The radial guide pipe is provided with a Venturi tube section in the annular drainage cavity. A drainage hole connected to the annular drainage cavity is provided at the narrow throat of the Venturi tube section. The annular drainage cavity is provided with an air inlet on the side facing the inlet end.

9. The burner nozzle structure for improving fuel distribution characteristics according to claim 7, characterized in that: The radial flow guide tube is provided with an elastic flow balancing piece. When the channel resistance of a radial flow guide tube increases, the flow balancing piece automatically deforms to increase the flow area, or when the flow of the radial flow guide tube is too high, the flow balancing piece is compressed and deformed to reduce the flow area.

10. A burner nozzle structure for improving fuel distribution characteristics according to claim 9, characterized in that: The flow balancing piece is a circular thin sheet structure, the edge of which is fixed on the radial guide tube, and the central area is in a free state and deforms with the fuel flow and pressure. A circular mainstream through hole is provided in the center of the flow balancing piece, and a plurality of auxiliary adjustment holes are provided around the mainstream through hole. A flow tube is provided on the auxiliary adjustment hole. One end of the flow tube is fixed on the auxiliary adjustment hole, and the other end is a free end, and the free end is set as an oblique cut. The opening of the oblique cut faces the inner wall of the radial guide tube. When the flow balancing piece is deformed, the free end is controlled to deflect and swing so that the oblique cut fits the inner wall of the radial guide tube and closes the auxiliary adjustment hole.

Images