Low-pressure-loss anti-backfire hydrogen fuel micro-premixing combustion chamber

Abstract

A low-pressure-loss anti-backfire hydrogen fuel micro-premixing combustion chamber comprises an inner barrel, an outer barrel, a cover, a fuel supply pipe and a combustion nozzle. An air supply channel is formed between the outer barrel and the inner barrel; a fuel cavity is formed between the cover body and the axial end wall plate of the outer cylinder body; the fuel supply pipe is communicated with the fuel cavity; a plurality of combustion nozzles are arranged on an axial end wall plate of the inner barrel in an array form; a fuel inlet hole is formed in an axial end wall plate of the outer barrel; the combustion nozzle comprises an inner sleeve, an outer sleeve and a bluff body; the outer sleeve is divided into a cylindrical section and a conical section; a tapered premixing cavity is formed between the conical section and the inner sleeve; a rectifier is arranged between the bluff body and the conical section; a plurality of rows of fuel outlet holes are formed in the inner sleeve; an air inlet cavity is formed between the cylindrical section and the inner sleeve; and an air inlet hole is formed in the axial end wall plate of the inner cylinder. Efficient micro-premixing of hydrogen fuel and air can be achieved, tempering can be effectively inhibited, pressure loss can be reduced, flame stability can be maintained, and NOx generation can be controlled.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas turbines, and particularly relates to a low-pressure-loss anti-backfire hydrogen fuel micro-premixed combustion chamber. BACKGROUND

[0002] Traditional gas turbines use natural gas and oil-based fuels as the main fuel, and carbon-containing compounds such as CO2, CO, UHC, etc. are generated during the combustion process. CO2 is the main greenhouse gas, and CO, UHC, etc. are the main pollutants. In order to meet the demand for low-carbon transformation, the use of hydrogen-rich or pure hydrogen fuel to replace traditional natural gas has become an important development direction for gas turbines. The combustion chamber is the core component of the gas turbine that completes fuel combustion and releases heat energy. The combustion nozzle is the key part of the combustion chamber that maintains flame combustion and organizes the flame. However, hydrogen has the characteristics of fast combustion speed, high flame temperature, and easy backfire, which poses a severe challenge to the design and operation of lean fuel premixed combustion chambers. Existing combustion technologies often have difficulty in balancing high efficiency, low emissions, and stable combustion in a wide load range, especially when the fuel is transitioning from natural gas to high-hydrogen or even pure hydrogen. There is a lack of combustion solutions that can ensure safety and environmental performance.

[0003] The fuel used by gas turbines is gradually transitioning from natural gas and oil-based fuels to hydrogen fuel or hydrogen-containing fuel. The main pollutant emission is NOx, which can be divided into thermal, rapid, and fuel types according to its formation path. During the improvement of combustion efficiency and combustion temperature in the combustion chamber, thermal NOx occupies a dominant position. The fuel premixing method of the combustion chamber is divided into two categories: swirl premixing and micro-mixing. However, due to the low density and weak jet penetration of hydrogen, it cannot be fully mixed in high-flow and high-speed inlet air flow, so swirl premixing has a strong backflow area, which can cause backfire to occur more easily.

[0004] Micro-mixing combustion technology reduces the mixing scale of fuel and air to the maximum extent, allowing fuel and oxidizer to mix uniformly on a smaller time scale. Small-scale nozzles can reduce the risk of backfire to some extent. Due to the shortening of the nozzle size, the mixing of fuel and oxidizer is mainly accelerated by turbulence, thereby improving the mixing uniformity at the nozzle outlet and allowing the chemical energy of the fuel to be fully released in a very short time. Due to the absence of a strong high-temperature backflow area, the residence time of flue gas in the high-temperature combustion area is shortened, achieving the effect of reducing thermal NOx. The shortening of the high-temperature area also protects the gas turbine to some extent. Therefore, micro-mixing combustion technology has become the preferred technical route for the transition of fuel used by gas turbines from natural gas and oil-based fuels to hydrogen fuel or hydrogen-containing fuel.

[0005] However, under the micro-mixing combustion technology route, how to realize efficient micro-premixing of hydrogen fuel and air in the hydrogen fuel micro-premixed combustion chamber, effectively inhibit backfire, reduce pressure loss, maintain flame stability, and control the generation of NOx has become a technical problem to be solved. SUMMARY

[0006] In view of the problems in the prior art, the present application provides a low-pressure-loss backfire-preventing hydrogen fuel micro-premixed combustion chamber, which can realize efficient micro-premixing of hydrogen fuel and air, effectively inhibit backfire, reduce pressure loss, maintain flame stability, and effectively control the generation of NOx.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: a low-pressure-loss backfire-preventing hydrogen fuel micro-premixed combustion chamber, comprising an inner cylinder, an outer cylinder, a cover body, a fuel supply pipe and a combustion nozzle; the inner cylinder and the outer cylinder are both single-side open structure, the outer cylinder is coaxially sleeved outside the inner cylinder, and the gap chamber between the outer cylinder and the inner cylinder is used as an air supply passage; the cover body is fixedly arranged outside the axial end wall plate of the outer cylinder, and a fuel cavity is formed between the cover body and the axial end wall plate of the outer cylinder; the fuel supply pipe is fixedly connected to the cover body, and the fuel supply pipe is in communication with the fuel cavity; the number of combustion nozzles is several, and the several combustion nozzles are arranged in an array on the axial end wall plate of the inner cylinder.

[0008] A plurality of fuel inlet holes are arranged on the axial end wall plate of the outer cylinder, and the number of fuel inlet holes is equal to the number of combustion nozzles and corresponds one-to-one.

[0009] The combustion nozzle comprises an inner sleeve, an outer sleeve and a bluff body; the inner sleeve penetrates through the axial end wall plate of the inner cylinder, and the central axis of the inner sleeve is parallelly distributed with the central axis of the inner cylinder; one end of the inner sleeve is located inside the inner cylinder, and the other end of the inner sleeve is located inside the air supply passage and is in communication with the fuel inlet hole; the bluff body is located inside the inner cylinder and is fixedly arranged at the end of the inner sleeve; the outer sleeve is coaxially sleeved outside the inner sleeve, and the outer sleeve is fixedly connected with the axial end wall plate of the inner cylinder.

[0010] The outer sleeve adopts a two-section structure, which is a cylindrical section and a conical section; one end of the cylindrical section is fixedly connected with the axial end wall plate of the inner cylinder, the other end of the cylindrical section is fixedly connected with the large-diameter end of the conical section, and the small-diameter end of the conical section is distributed on the same side as the bluff body.

[0011] The annular space between the conical section and the inner sleeve constitutes a tapered premixing cavity.

[0012] A flow regulator is fixedly arranged between the bluff body and the conical section in the downstream region of the tapered premixing cavity; the flow regulator includes but is not limited to a flow regulating fin, a flow regulating rib, a flow regulating wing and a flow regulating partition plate.

[0013] Several fuel outlet holes are provided on the inner sleeve within the range of the tapered premixing chamber. The fuel outlet holes are arranged in multiple rows, and the fuel outlet holes in each row are evenly distributed along the circumference of the inner sleeve.

[0014] In the axial direction of the inner sleeve, the diameter of several rows of fuel outlet holes decreases progressively. The fuel outlet holes in the row adjacent to the large-diameter end of the conical section of the outer sleeve have the largest diameter, and the fuel outlet holes in the row adjacent to the small-diameter end of the conical section of the outer sleeve have the smallest diameter. All fuel outlet holes in the same row have the same diameter. The shape of the fuel outlet holes includes, but is not limited to, circles, squares, and triangles. The central axis of the fuel outlet holes is perpendicular to or at an angle to the central axis of the inner sleeve. The tapered premixing chamber is connected to the fuel chamber in sequence through the fuel outlet holes, the inner cavity of the inner sleeve, and the fuel inlet hole.

[0015] The circumferential space between the cylindrical section and the inner sleeve forms an air intake chamber.

[0016] A number of air inlet holes are provided on the axial end wall plate of the inner cylinder directly opposite the air inlet chamber. The air inlet holes are evenly distributed along the circumference of the inner sleeve. The air inlet chamber is connected to the air supply channel through the air inlet holes.

[0017] The beneficial effects of this invention are: The low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber of this invention features air inlets at each nozzle arranged in a circumferentially uniform pattern. Air enters the air intake chamber evenly through these inlets, ensuring a symmetrical and uniform air supply to the nozzles. This effectively organizes airflow direction and reduces local flow velocity through the multi-hole uniform air intake, preventing excessive pressure loss. Furthermore, the air intake chamber and the tapered premixing chamber are linearly distributed, allowing for reverse air supply. This effectively extends the residence time of air within the nozzles, providing more time for thorough mixing of air and hydrogen fuel, reducing localized excessive fuel concentration, and minimizing NOx emissions during combustion. X It provides the necessary support for emissions.

[0018] The low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber of the present invention has each nozzle independently connected to a fuel inlet, and hydrogen fuel can be evenly distributed to all nozzles through the fuel inlet, thereby achieving uniformity of hydrogen fuel supply. In addition, the fuel outlets are arranged in multiple rows along the axial direction of the inner sleeve, and the diameter of the fuel outlets decreases progressively with each row. When hydrogen fuel is injected into the converging premixing chamber through the fuel outlets at different locations, it enters the converging premixing chamber in multiple streams with small flow rates. The fuel outlets with larger diameters have a larger flow area and a smaller local resistance coefficient, so they can carry the main part of the total hydrogen fuel flow and enter the periphery of the converging premixing chamber smoothly at a relatively low flow rate. The fuel outlets with smaller diameters have a smaller flow area and can generate high-speed jets. Therefore, the high penetrating power of the high-speed jets can be used to allow this part of the hydrogen fuel to penetrate into the core area of ​​the air flow and generate a strong turbulent flow field. This achieves the effect of rapid and uniform mixing of hydrogen fuel and air over a short distance. Through this synergistic effect, pressure loss can be reduced and hydrogen fuel can be rapidly diffused in the air flow field, thereby achieving rapid and uniform mixing of hydrogen fuel and air at the microscale.

[0019] The low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber of this invention, through the tapered structure of the tapered premixing chamber, significantly increases the flow velocity of the hydrogen-air mixture as it exits the nozzle, effectively suppressing backfire and thus improving the safety and durability of the nozzle operation. Furthermore, the rectifier effectively suppresses irregular eddies and lateral disturbances in the mixed gas flow, resulting in a more uniform velocity and pressure distribution of the mixture exiting the nozzle. This leads to a stable laminar flow, crucial for forming a stable, separated flame. By keeping the flame front stably positioned a certain distance in front of the nozzle, direct backflow or adhesion of the high-temperature flame to the nozzle body is effectively prevented, fundamentally improving nozzle operational safety. This not only prevents the nozzle head from being burned by high temperatures but also causes the combustion reaction zone to shift upwards and the flame morphology to stabilize, creating conditions for efficient and uniform combustion. It effectively suppresses NOx formation caused by high temperatures, resulting in lower pollutant emissions. Attached Figure Description

[0020] Figure 1 This is a perspective view (partial cross-section) of a low-pressure-loss, backfire-preventing hydrogen fuel micro-premixed combustion chamber according to the present invention. Figure 2 This is a top view of a low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to the present invention. Figure 3 for Figure 2 Sectional view of AA; Figure 4 This is a front view of the combustion nozzle (overall cross-section) of the present invention; In the figure, 1—inner cylinder, 2—outer cylinder, 3—shroud, 4—fuel supply pipe, 5—combustion nozzle, 6—air supply channel, 7—fuel chamber, 8—fuel inlet, 9—inner sleeve, 10—outer sleeve, 11—cylindrical section, 12—conical section, 13—gradually narrowing premixing chamber, 14—rectifier, 15—fuel outlet, 16—air inlet chamber, 17—air inlet, 18—blunt body. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1 to 4 As shown, a low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber includes an inner cylinder 1, an outer cylinder 2, a cover 3, a fuel supply pipe 4, and combustion nozzles 5. Both the inner cylinder 1 and the outer cylinder 2 are single-sided open structures. The outer cylinder 2 is coaxially fitted onto the outside of the inner cylinder 1, and the gap between the outer cylinder 2 and the inner cylinder 1 serves as an air supply channel 6. The cover 3 is fixedly installed outside the axial end wall of the outer cylinder 2, forming a fuel chamber 7 between the cover 3 and the axial end wall of the outer cylinder 2. The fuel supply pipe 4 is fixedly connected to the cover 3 and communicates with the fuel chamber 7. The number of combustion nozzles 5 is several, and these nozzles 5 are arranged in an array on the axial end wall of the inner cylinder 1.

[0023] A plurality of fuel inlet holes 8 are provided on the axial end wall plate of the outer cylinder 2. The number of fuel inlet holes 8 is equal to that of the combustion nozzles 5 and their positions correspond one-to-one.

[0024] The combustion nozzle 5 includes an inner sleeve 9, an outer sleeve 10, and a blunt body 18. The inner sleeve 9 is sealed through the axial end wall of the inner cylinder 1, and the central axis of the inner sleeve 9 is parallel to the central axis of the inner cylinder 1. One end of the inner sleeve 9 is located inside the inner cylinder 1, and the other end of the inner sleeve is located inside the air supply channel 6 and connected to the fuel inlet 8. The blunt body 18 is located inside the inner cylinder 1 and is fixedly installed at the end of the inner sleeve 9. The outer sleeve 10 is coaxially fitted on the outside of the inner sleeve 9, and the outer sleeve 10 is fixedly connected to the axial end wall of the inner cylinder 1.

[0025] The outer sleeve 10 adopts a two-section structure, namely a cylindrical section 11 and a conical section 12; one end of the cylindrical section 11 is fixedly connected to the axial end wall plate of the inner cylinder 1, and the other end of the cylindrical section 11 is fixedly connected to the large diameter end of the conical section 12, and the small diameter end of the conical section 12 is distributed on the same side as the blunt body 18.

[0026] The circumferential space between the conical section 12 and the inner sleeve 9 forms a tapered premixing cavity 13.

[0027] A rectifier 14 is fixedly disposed between the blunt body 18 and the conical section 12 in the downstream region of the tapered premixing cavity 13; the rectifier 14 includes, but is not limited to, rectifier blades, rectifier ribs, rectifier wings, and rectifier baffles.

[0028] A number of fuel outlet holes 15 are provided on the inner sleeve 9 within the range of the tapered premixing chamber 13. The fuel outlet holes 15 are arranged in multiple rows, and the fuel outlet holes 15 in each row are evenly distributed along the circumference of the inner sleeve 9.

[0029] In the axial direction of the inner sleeve 9, the diameter of several rows of fuel outlet holes 15 decreases progressively. The fuel outlet holes 15 in the row adjacent to the large-diameter end of the conical section 12 of the outer sleeve 10 have the largest diameter, and the fuel outlet holes 15 in the row adjacent to the small-diameter end of the conical section 12 of the outer sleeve 10 have the smallest diameter. All fuel outlet holes 15 in the same row have the same diameter. The shape of the fuel outlet holes 15 includes, but is not limited to, circles, squares, and triangles. The central axis of the fuel outlet holes 15 is perpendicular to or at an angle to the central axis of the inner sleeve 9. The tapered premixing chamber 13 is connected to the fuel chamber 7 in sequence through the fuel outlet holes 15, the inner cavity of the inner sleeve 9, and the fuel inlet hole 8.

[0030] The circumferential space between the cylindrical section 11 and the inner sleeve 9 forms an air intake chamber 16.

[0031] A plurality of air inlet holes 17 are provided on the axial end wall plate of the inner cylinder 1 directly opposite the air inlet chamber 16. The plurality of air inlet holes 17 are evenly distributed along the circumferential direction of the inner sleeve 9. The air inlet chamber 16 is connected to the air supply channel 6 through the air inlet holes 17.

[0032] The following describes a single use of the present invention with reference to the accompanying drawings: During combustion chamber operation, air enters the converging premixing chamber 13 sequentially through air supply channel 6, air inlet 17, and air inlet cavity 16, ensuring that each nozzle receives an equal amount of air. Hydrogen fuel enters the converging premixing chamber 13 sequentially through fuel supply pipe 4, fuel cavity 7, fuel inlet 8, inner cavity of inner sleeve 9, and fuel outlet 15, ensuring that each nozzle receives an equal amount of hydrogen fuel. This achieves thorough premixing of air and hydrogen fuel within the nozzle. As the mixed air and hydrogen fuel flow out of the nozzle, the flame distribution becomes more uniform, effectively suppressing excessive local heat load.

[0033] Since the air inlets 17 at each nozzle are arranged in a circumferentially uniform manner, air can enter the air intake chamber 16 evenly after passing through the air inlets 17. This ensures that air is supplied to the nozzle in a symmetrical and uniform manner, achieving uniform air supply. This effectively organizes the airflow direction and reduces local flow velocity through the multi-hole uniform air intake method, avoiding excessive pressure loss. In addition, the air intake chamber 16 and the tapered premixing chamber 13 are distributed in a straight line, achieving reverse air supply. This effectively extends the residence time of air in the nozzle, providing more time for the air and hydrogen fuel to mix fully. This reduces the phenomenon of excessively high local fuel concentration and helps reduce NO emissions during combustion. X It provides the necessary support for emissions.

[0034] Since each nozzle is independently connected to a fuel inlet 8, hydrogen fuel can be evenly distributed to all combustion nozzles 5 through the fuel inlet 8, achieving uniform hydrogen fuel supply. In addition, the fuel outlets 15 are arranged in multiple rows in the axial direction of the inner sleeve 9, and the orifice size of several rows of fuel outlets 15 decreases progressively. Therefore, when hydrogen fuel is injected into the tapered premixing chamber 13 through the fuel outlets 15 at different positions, the hydrogen fuel enters the tapered premixing chamber 13 in multiple streams with small flow rates. The fuel outlets 15 with larger orifice sizes, due to their large flow area and small local resistance coefficient, are used to bear the main part of the total hydrogen fuel flow and can enter the periphery of the tapered premixing chamber 13 smoothly at a relatively low flow rate. The fuel outlets 15 with smaller orifice sizes, due to their small flow area, can generate high-speed jets. Therefore, the high penetrating power of the high-speed jets can be used to make this part of the hydrogen fuel penetrate into the core area of ​​the air flow and generate a strong turbulent flow field, thereby achieving the effect of rapid and uniform mixing of hydrogen fuel and air in a short distance. Therefore, the fuel outlet 15 with a larger aperture size dominates the low-resistance flow, while the fuel outlet 15 with a smaller aperture size focuses on efficient mixing. Through the synergistic effect of the two, pressure loss can be reduced and hydrogen fuel can be rapidly diffused in the air flow field, thereby achieving rapid and uniform mixing of hydrogen fuel and air at the microscale.

[0035] Due to the tapered structure of the premixed chamber 13, the flow velocity of the hydrogen fuel-air mixture can be significantly increased during the exit of the nozzle, effectively suppressing backfire and thus improving the safety and durability of the nozzle operation. Furthermore, the rectifier 14 effectively suppresses irregular eddies and lateral disturbances in the mixed gas flow, resulting in a more uniform velocity and pressure distribution of the mixture exiting the nozzle. This allows for stable laminar flow, which is crucial for forming a stable, separated flame. By keeping the flame front stably positioned a certain distance in front of the nozzle, direct backflow or adhesion of the high-temperature flame to the nozzle body can be effectively avoided, fundamentally improving nozzle operation safety. This not only prevents the nozzle head from being burned by high temperatures but also causes the combustion reaction zone to shift upwards and the flame shape to stabilize, creating conditions for efficient and uniform combustion. This effectively suppresses NOx formation caused by high temperatures, resulting in lower pollutant emissions.

[0036] The solutions described in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the present invention are included within the scope of protection of the present invention.

Claims

1. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber, characterized in that: It includes an inner cylinder, an outer cylinder, a cover, a fuel supply pipe, and combustion nozzles; both the inner and outer cylinders are single-sided open structures, with the outer cylinder coaxially fitted onto the outside of the inner cylinder, and the gap between the outer and inner cylinders serving as an air supply channel; the cover is fixedly installed on the outside of the axial end wall of the outer cylinder, forming a fuel chamber between the cover and the axial end wall of the outer cylinder; the fuel supply pipe is fixedly connected to the cover and communicates with the fuel chamber; the number of combustion nozzles is several, and the several combustion nozzles are arranged in an array on the axial end wall of the inner cylinder.

2. The low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 1, characterized in that: Several fuel inlets are provided on the axial end wall plate of the outer cylinder, and the number of fuel inlets is equal to that of the combustion nozzles and their positions correspond one-to-one.

3. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 2, characterized in that: The combustion nozzle includes an inner sleeve, an outer sleeve, and a blunt body; the inner sleeve is sealed through the axial end wall plate of the inner cylinder, and the central axis of the inner sleeve is parallel to the central axis of the inner cylinder; one end of the inner sleeve is located inside the inner cylinder, and the other end of the inner sleeve is located in the air supply channel and connected to the fuel inlet; the blunt body is located inside the inner cylinder and is fixedly installed at the end of the inner sleeve; the outer sleeve is coaxially fitted on the outside of the inner sleeve, and the outer sleeve is fixedly connected to the axial end wall plate of the inner cylinder.

4. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 3, characterized in that: The outer sleeve adopts a two-section structure, namely a cylindrical section and a conical section; one end of the cylindrical section is fixedly connected to the axial end wall plate of the inner cylinder, and the other end of the cylindrical section is fixedly connected to the large-diameter end of the conical section, while the small-diameter end of the conical section is distributed on the same side as the blunt body.

5. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 4, characterized in that: The circumferential space between the conical section and the inner sleeve forms a gradually narrowing premixing cavity.

6. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 5, characterized in that: A rectifier is fixedly installed between the blunt body and the conical section in the downstream region of the tapered premixing cavity; the rectifier includes, but is not limited to, rectifier blades, rectifier ribs, rectifier vanes, and rectifier baffles.

7. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 5, characterized in that: Several fuel outlet holes are provided on the inner sleeve within the range of the tapered premixing chamber. The fuel outlet holes are arranged in multiple rows, and the fuel outlet holes in each row are evenly distributed along the circumference of the inner sleeve.

8. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 7, characterized in that: In the axial direction of the inner sleeve, the diameter of several rows of fuel outlet holes decreases progressively. The fuel outlet holes in the row adjacent to the large-diameter end of the conical section of the outer sleeve have the largest diameter, and the fuel outlet holes in the row adjacent to the small-diameter end of the conical section of the outer sleeve have the smallest diameter. All fuel outlet holes in the same row have the same diameter. The shape of the fuel outlet holes includes, but is not limited to, circles, squares, and triangles. The central axis of the fuel outlet holes is perpendicular to or at an angle to the central axis of the inner sleeve. The tapered premixing chamber is connected to the fuel chamber in sequence through the fuel outlet holes, the inner cavity of the inner sleeve, and the fuel inlet hole.

9. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 4, characterized in that: The circumferential space between the cylindrical section and the inner sleeve forms an air intake chamber.

10. A low-pressure-loss, backfire-premixed hydrogen fuel combustion chamber according to claim 9, characterized in that: A number of air inlet holes are provided on the axial end wall plate of the inner cylinder directly opposite the air inlet chamber. The air inlet holes are evenly distributed along the circumference of the inner sleeve. The air inlet chamber is connected to the air supply channel through the air inlet holes.

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