Premixing knob combustion head and combustion method

Abstract

The invention relates to the technical field of hydrogen combustion, and discloses a premixing knob combustion head, a combustion method and an air inlet disc, the air inlet disc is provided with an air inlet pipeline, and a plurality of injection pipes are arranged in the circumferential direction of the circle center of the air inlet disc and used for outputting hydrogen entering from the air inlet pipeline; the premixing disc is arranged on one side of the air inlet disc, a gap is formed between the premixing disc and the air inlet disc and used for allowing air to enter the premixing disc, the premixing disc is provided with a plurality of mixing channels, each mixing channel comprises a premixing section and a knob section, the multiple injection pipes extend into the premixing sections respectively, the diameter of the premixing sections is larger than that of the injection pipes, and the knob sections are arranged in the premixing sections. The injection pipe and the premixing section are coaxially arranged; the multiple knob sections converge towards the circle center direction of the premixing disc and circumferentially deflect around the circle center at the same time so that mixed gas in the premixing sections can form rotational flow, and hydrogen and air can be evenly mixed, the tempering phenomenon can be effectively prevented, the combustion stability can be improved, and nitrogen oxide emission can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen combustion and discloses a premixed rotary combustion head and a combustion method. Background Art

[0002] The main function of the combustion chamber of aircraft engines and industrial gas turbines is to carry out combustion reactions, convert the chemical energy of the fuel into thermal energy, heat the incoming flow, and improve the working capacity of the working fluid.

[0003] In the conventional radial swirl combustor head configuration, the fuel is injected into the incoming air at a vertical angle (cross-flow penetration) to achieve rapid mixing within a short mixing distance. However, the depth of fuel penetration and the trajectory of the fuel jet are affected by the momentum ratio of the fuel jet to the incoming air (J=ρV j 2 / ρV ∞ 2 )’s impact.

[0004] When the momentum ratio is low, the fuel penetration depth is shallow, meaning that fuel tends to accumulate on the mixing section wall on the same side of the fuel nozzle. Due to viscosity, the flow velocity near the wall is relatively low. This fuel accumulation increases the risk of flame persistence near the wall, especially considering the rapid flame propagation of hydrogen. This also means that when using hydrogen as the fuel in the mixing section of a traditional radial swirler (crossflow penetration configuration), the risk of flashback may increase when the momentum is low.

[0005] When the momentum ratio is too large, the hydrogen penetration intensity is too large, and the hydrogen jet reaches and accumulates on the upper wall of the mixing section, which also increases the risk of flame persistence on the upper wall.

[0006] Even when the momentum ratio is moderate, the trajectory and mixing quality of the hydrogen jet will still be affected by the change in momentum ratio caused by the change in operating conditions (from small operating conditions to large operating conditions), which means that the fuel distribution, temperature field distribution and NOx emissions in the downstream combustion zone will also be affected.

[0007] Chinese patent (publication number: CN116481053A) discloses a hydrogen-rich fuel combustion nozzle, a head burner and a combustion chamber. The combustion working principle of the central combustion unit is as follows: Figure 6 As shown: the fuel passes through the fuel annulus, passes through the flow channel inside the conical outlet annulus, and enters the combustion area from the fuel nozzle hole. The fuel injection hole and the outer ring air flow channel form a vertical jet. The hole position is downstream of the outer ring air flow channel and has no premixing channel with the outer ring air. It is diffusion combustion. It is known from the above-mentioned public patent that the fuel injection hole and the outer ring air flow channel form a vertical jet, which is easy to cause backfire.

[0008] Therefore, the present application provides a premixed twist combustion head and a combustion method to solve the above technical problems. SUMMARY

[0009] The present application aims to provide a premixed swirl combustion head and a combustion method, which can realize uniform mixing of hydrogen and air, effectively prevent backfire phenomenon, improve combustion stability and reduce nitrogen oxide emission.

[0010] In order to achieve the above technical effects, the technical scheme adopted by the present application is as follows: a premixed swirl combustion head, comprising: An air inlet disc is provided with an air inlet pipeline, and a plurality of injection pipes are arranged along the circumferential direction of the air inlet disc, which are used to output hydrogen entering from the air inlet pipeline; A premixing disc is arranged on one side of the air inlet disc, and a gap is formed between the premixing disc and the air inlet disc for air to enter the premixing disc, the premixing disc is provided with a plurality of mixing channels, the mixing channels include a premixing section and a swirl section, a plurality of injection pipes respectively extend into the premixing section, and the diameter of the premixing section is greater than the diameter of the injection pipe, the injection pipe is coaxially arranged with the premixing section; a plurality of swirl sections converge towards the center of the premixing disc, and the swirl sections are deflected along the circumferential direction of the center of the premixing disc, which are used to form a swirling flow of the mixed gas in the premixing section.

[0011] As a preferred embodiment, the swirl section includes a radial deflection section and a circumferential deflection section, the radial deflection section has an angle of 0-30° with the axis of the premixing disc, and the circumferential deflection section has an angle of 0-60° with the axis of the premixing disc.

[0012] As a preferred embodiment, a partition is arranged in the air inlet disc, which divides the air inlet disc into an inner air inlet chamber and an outer air inlet chamber; the air inlet pipeline includes an inner air inlet pipeline and an outer air inlet pipeline, the inner air inlet pipeline communicates with the inner air inlet chamber, and the outer air inlet pipeline communicates with the outer air inlet chamber.

[0013] As a preferred embodiment, the length of the injection pipe extending into the premixing section is 1.3-2.6mm, so that the hydrogen is wrapped in the center position of the premixing section after being injected, reducing the risk of wall layer backfire.

[0014] As a preferred embodiment, the length of the premixing section is 3-5 times the diameter of the injection pipe, which ensures that the hydrogen and air are fully mixed in the premixing section to form a uniform premixed gas.

[0015] As a preferred embodiment, a flame lifting hole is arranged on the premixing disc, the flame lifting hole is coaxially arranged with the air inlet disc, a flame lifting pipeline is arranged on the air inlet disc, which is used to output hydrogen in the air inlet disc, the flame lifting pipeline is coaxially arranged with the flame lifting hole, the flame lifting pipeline extends into the flame lifting hole, and the diameter of the flame lifting hole is greater than the diameter of the flame lifting pipeline.

[0016] To achieve the above technical effects, the application further provides a combustion method of the premixed swirl combustion head, comprising the following steps: Hydrogen is input through the air inlet pipeline of the air inlet disc; The hydrogen is output through a plurality of jet pipes arranged circumferentially along the center of the air inlet disc; Air is input into the premixing disc through the gap between the air inlet disc and the premixing disc; The hydrogen output by the jet pipes is input into the premixing section of the mixing channel of the premixing disc, the premixing section has a diameter larger than that of the jet pipes and is coaxially arranged with the jet pipes, and the preliminary mixing of hydrogen and air is realized in the premixing section; The preliminarily mixed gas is introduced into the combustion chamber for combustion after being introduced into the swirl section of the premixing disc which converges towards the center of the premixing disc to form a swirling flow and further promote the mixing.

[0017] As a preferred embodiment, the swirl section comprises a radial deflection section and a circumferential deflection section, the radial deflection section has an angle of 0-30° with the axis of the premixing disc, the circumferential deflection section has an angle of 0-60° with the axis of the premixing disc, the gas converges towards the center through the radial deflection section to accelerate the outlet speed of the premixing disc and lift the flame to avoid burning of the flame surface on the outlet wall of the premixing disc; the gas forms a swirling flow in a specific direction when passing through the circumferential deflection section to form a stable swirling backflow area downstream of the premixing disc and stabilize the flame within the swirling backflow area.

[0018] As a preferred embodiment, a partition is arranged in the air inlet disc, the partition divides the air inlet disc into an inner air inlet chamber and an outer air inlet chamber; the air inlet pipeline comprises an inner air inlet pipeline and an outer air inlet pipeline, the inner air inlet pipeline is communicated with the inner air inlet chamber, and the outer air inlet pipeline is communicated with the outer air inlet chamber; the method comprises the steps of inputting hydrogen into the inner air inlet pipeline and the outer air inlet pipeline respectively to make the hydrogen enter the inner air inlet chamber and the outer air inlet chamber respectively.

[0019] As a preferred embodiment, the method further comprises the following steps: Part of the hydrogen is output through the flame lifting pipeline on the air inlet disc; The hydrogen output by the flame lifting pipeline is output through the flame lifting hole on the premixing disc coaxially arranged with the flame lifting pipeline, the flame lifting pipeline extends into the flame lifting hole, and the diameter of the flame lifting hole is larger than that of the flame lifting pipeline.

[0020] Compared with the prior art, the application has the following beneficial effects: I. Uniform mixing: through the design of the premixing section and the swirl section, the hydrogen and air are fully and uniformly mixed, a uniform equivalence ratio is generated, hot spots are avoided, and nitrogen oxide emissions are reduced.

[0021] II. Anti-backfire: The specific length of the injection pipe extending into the premixing section is designed to make the hydrogen gas injected wrapped by air in the center of the premixing section, effectively reducing the risk of wall layer backfire.

[0022] III. Combustion stability: The circumferential deflection of the twist section forms a swirl, which helps to stabilize the flame and improve the stability of combustion.

[0023] IV. Head thermal protection: The radial deflection of the twist section converges to the center, accelerates the flow velocity at the outlet of the premixing section, lifts the flame, and avoids the flame surface sticking to the outlet wall of the premixing disc to cause burning; at the same time, the design of the flame lifting hole and the flame lifting pipe at the center also has a similar effect, which is beneficial to lifting the bottom of the flame surface.

[0024] V. Flexible control: The inlet disc is divided into an inner inlet chamber and an outer inlet chamber, which can control the hydrogen supply of different areas respectively, and adapt to different combustion working condition requirements. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the overall three-dimensional structure of the present application; Figure 2 is one of the front views of the present application; Figure 3 is the A-A sectional view of Figure 2 ; Figure 4 is the A-A sectional view of Figure 2 ; Figure 5 is a schematic diagram of part of the three-dimensional structure of the present application; Figure 6 is a schematic diagram of the inside of the premixing disc of the present application.

[0026] REFERENCE NUMERALS: 1, inlet disc; 11, inlet pipe; 12, injection pipe; 2, premixing disc; 21, mixing channel; 210, premixing section; 211, twist section; 2111, radial deflection section; 2112, circumferential deflection section; 3, partition; 31, inner inlet chamber; 32, outer inlet chamber; 33, inner inlet pipe; 34, outer inlet pipe; 4, flame lifting hole; 41, flame lifting pipe. DETAILED DESCRIPTION

[0027] The present application will be further described in conjunction with the embodiments and drawings. However, it should not be understood that the scope of the above-mentioned subject matter of the present application is limited to the following embodiments, and any technology realized based on the content of the present application falls within the scope of the present application.

[0028] Example 1, as Figure 1 ,2 , 3, 4, a premixed swirl combustion head, comprising an air inlet disc 1 and a premix disc 2. The air inlet disc 1 is provided with an air inlet pipe 11, and a plurality of jet pipes 12 are arranged along the circumferential center of the air inlet disc 1, for outputting hydrogen entering from the air inlet pipe 11. The premix disc 2 is arranged on one side of the air inlet disc 1, and a gap is formed between the premix disc 2 and the air inlet disc 1 for air to enter the premix disc 2. The premix disc 2 is provided with a plurality of mixing channels 21, the mixing channel 21 comprises a premixing section 210 and a swirl section 211, a plurality of jet pipes 12 respectively extend into the premixing section 210, and the diameter of the premixing section 210 is greater than the diameter of the jet pipe 12, and the jet pipe 12 is coaxially arranged with the premixing section 210; as shown in Figure 6 , a plurality of swirl sections 211 converge towards the center of the premix disc 2, accelerating the airflow at the outlet of the premix disc 2, lifting the flame, and avoiding the flame surface from sticking to the outlet wall of the premix disc 2 to cause burning; as shown in Figure 5 , the swirl section 211 is deflected around the circumferential center, forming a swirling flow, generating a backflow area downstream, and stabilizing combustion.

[0029] As a preferred scheme of this embodiment, as shown in Figure 3 , 5 , the swirl section 211 comprises a radial deflection section 2111 and a circumferential deflection section 2112, the radial deflection section 2111 has an angle of 0-30° with the axis of the premix disc 2, and the circumferential deflection section 2112 has an angle of 0-60° with the axis of the premix disc 2.

[0030] As shown in Figure 3 , a partition 3 is arranged in the air inlet disc 1, the partition 3 divides the air inlet disc 1 into an inner air inlet chamber 31 and an outer air inlet chamber 32; the air inlet pipe 11 comprises an inner air inlet pipe 33 and an outer air inlet pipe 34, the inner air inlet pipe 33 communicates with the inner air inlet chamber 31, and the outer air inlet pipe 34 communicates with the outer air inlet chamber 32.

[0031] As shown in Figure 3 , the length of the jet pipe 12 extending into the premixing section 210 is 1.3-2.6mm, so that the hydrogen after being sprayed is wrapped in the center position of the premixing section 210 by air, reducing the risk of wall layer reheating.

[0032] The length of the premixing section 210 is 3-5 times the diameter of the jet pipe 12, ensuring that hydrogen and air are fully mixed in the premixing section 210 to form a uniform premixed gas.

[0033] As shown in Figure 2 , 3As shown, the premixing disc 2 is provided with a flame lifting hole 4, and the air inlet disc 1 is provided with a flame lifting pipeline 41 for outputting hydrogen in the air inlet disc 1, the flame lifting pipeline 41 is coaxially arranged with the flame lifting hole 4, the flame lifting pipeline 41 extends into the flame lifting hole 4, and the diameter of the flame lifting hole 4 is greater than the diameter of the flame lifting pipeline 41.

[0034] In use, the premixing swirl combustion head of the present application comprises an air inlet disc 1 and a premixing disc 2, the air inlet disc 1 is provided with an air inlet pipeline 11, the air inlet pipeline 11 comprises an inner air inlet pipeline 33 and an outer air inlet pipeline 34, the air inlet disc 1 is provided with a partition plate 3, the partition plate 3 divides the air inlet disc 1 into an inner air inlet chamber 31 and an outer air inlet chamber 32, the inner air inlet pipeline 33 communicates with the inner air inlet chamber 31, and the outer air inlet pipeline 34 communicates with the outer air inlet chamber 32.

[0035] A plurality of injection pipes 12 are arranged along the circumcenter of the air inlet disc 1 for outputting hydrogen entering from the air inlet pipeline 11. The premixing disc 2 is arranged on one side of the air inlet disc 1, and a gap is formed between the premixing disc 2 and the air inlet disc 1 for air entering the premixing disc 2.

[0036] The premixing disc 2 is provided with a plurality of mixing channels 21, and each mixing channel 21 comprises a premixing section 210 and a swirl section 211. The plurality of injection pipes 12 respectively extend into the premixing section 210, and the diameter of the premixing section 210 is greater than the diameter of the injection pipe 12, and the injection pipe 12 is coaxially arranged with the premixing section 210. The length of the injection pipe 12 extending into the premixing section 210 is 1.3-2.6mm, and the length of the premixing section 210 is 3-5 times the diameter of the injection pipe 12.

[0037] As shown in Figure 2 , 3 , 5, the swirl section 211 comprises a radial deflection section 2111 and a circumferential deflection section 2112, the included angle δ between the radial deflection section 2111 and the axis of the premixing disc 2 is 0-30°, and the included angle θ between the circumferential deflection section 2112 and the axis of the premixing disc 2 is 0-60°.

[0038] As shown in Figure 6 , the plurality of swirl sections 211 all converge towards the circumcenter of the premixing disc 2 for accelerating the airflow of the mixed gas in the premixing section 210 at the outlet of the premixing disc 2 to lift the flame and avoid burning the outlet wall of the premixing disc 2 due to the adhesion of the flame surface; Figure 6 As shown in , the swirl section 211 deflects around the circumcenter to form a rotational flow to generate a backflow area downstream to stabilize combustion.

[0039] As shown in Figure 2 , 3As shown, the premixing disc 2 is provided with a flame lifting hole 4, and the air inlet disc 1 is provided with a flame lifting pipeline 41 for outputting hydrogen in the air inlet disc 1. The flame lifting pipeline 41 is coaxially arranged with the flame lifting hole 4, the flame lifting pipeline 41 extends into the flame lifting hole 4, and the diameter of the flame lifting hole 4 is greater than that of the flame lifting pipeline 41, so as to avoid the flame surface from adhering to the wall surface of the combustion head to cause burning.

[0040] Embodiment 2 is a combustion method of a premixing swirl combustion head, based on the premixing swirl combustion head, comprising the following steps: inputting hydrogen through the air inlet pipeline 11 of the air inlet disc 1; outputting the hydrogen through the plurality of jet pipes 12 arranged along the circumferential direction of the center of the air inlet disc 1; making air enter the premixing disc 2 through the gap between the air inlet disc 1 and the premixing disc 2; making the hydrogen output by the jet pipe 12 enter the premixing section 210 of the mixing channel 21 of the premixing disc 2, the premixing section 210 has a diameter greater than that of the jet pipe 12 and is coaxially arranged with the jet pipe 12, so as to realize the preliminary mixing of hydrogen and air in the premixing section 210; making the preliminarily mixed gas pass through the swirl section 211 converging to the center of the premixing disc 2, forming a swirl flow, further promoting the mixing, and introducing the premixed gas into the combustion chamber for combustion.

[0041] Through the above structure and method, the present application realizes the uniform mixing of hydrogen and air, effectively prevents the backfire phenomenon, improves the combustion stability, reduces the emission of nitrogen oxides, and has a good application prospect.

[0042] The above is only a preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A premixed rotary combustion head, characterized in that: include: An air intake disc (1), wherein the air intake disc (1) is provided with an air intake pipe (11), and a plurality of injection pipes (12) are provided along the circumference of the center of the air intake disc (1) for outputting hydrogen entering from the air intake pipe (11); A premixing disk (2) is provided on one side of the air inlet disk (1). A gap is formed between the premixing disk (2) and the air inlet disk (1) for air to enter the premixing disk (2). The premixing disk (2) is provided with a plurality of mixing channels (21). The mixing channels (21) include a premixing section (210) and a twisting section (211). The plurality of injection pipes (12) extend into the premixing section (210) respectively. The diameter of the premixing section (210) is larger than that of the injection pipe (12). The injection pipe (12) and the premixing section (210) are coaxially arranged. The plurality of twisting sections (211) converge toward the center of the premixing disk (2), and the twisting sections (211) deflect along the circumference of the center of the premixing disk (2) to form a swirl of the mixed gas in the premixing section (210).

2. The premixed twist combustion head according to claim 1, characterized in that: The twisting section (211) comprises a radial deflection section (2111) and a circumferential deflection section (2112); the radial deflection section (2111) and the axis of the premixing disc (2) have an included angle of 0-30°; and the circumferential deflection section (2112) and the axis of the premixing disc (2) have an included angle of 0-60°.

3. The premixed swirl combustion head according to claim 1, characterized in that: The air intake disk (1) is provided with a partition (3), and the partition (3) divides the interior of the air intake disk (1) into an inner air intake chamber (31) and an outer air intake chamber (32); the air intake pipe (11) includes an inner air intake pipe (33) and an outer air intake pipe (34), the inner air intake pipe (33) is communicated with the inner air intake chamber (31), and the outer air intake pipe (34) is communicated with the outer air intake chamber (32).

4. The premixed swirl combustion head according to claim 1, characterized in that: The injection pipe (12) extends into the premixing section (210) by a length of 1.3-2.6 mm, so that the hydrogen is wrapped by air at the center of the premixing section (210) after injection, thereby reducing the risk of flashback of the wall layer.

5. The premixed swirl combustion head according to claim 1, characterized in that: The length of the premixing section (210) is 3 to 5 times the diameter of the injection pipe (12), ensuring that the hydrogen and air are fully mixed in the premixing section (210) to form a uniform premixed gas.

6. The premixed swirl combustion head according to claim 1, characterized in that: The premixing disk (2) is provided with a flame lifting hole (4), and the flame lifting hole (4) is concentrically arranged with the premixing disk (2). The air intake disk (1) is provided with a flame lifting pipe (41) for outputting hydrogen in the air intake disk (1). The flame lifting pipe (41) is coaxially arranged with the flame lifting hole (4), and the flame lifting pipe (41) extends into the flame lifting hole (4), and the diameter of the flame lifting hole (4) is larger than the diameter of the flame lifting pipe (41).

7. A combustion method for a premixed rotary combustion head, characterized in that: The premixed swirl combustion head according to any one of claims 1 to 6 comprises the following steps: Hydrogen is introduced through the air inlet pipe (11) of the air inlet plate (1); The hydrogen is output through a plurality of injection pipes (12) arranged along the circumference of the center of the gas inlet disk (1); Allowing air to enter the premixing disk (2) through the gap between the air inlet disk (1) and the premixing disk (2); The hydrogen output from the injection pipe (12) enters the premixing section (210) of the mixing channel (21) of the premixing disk (2), wherein the diameter of the premixing section (210) is larger than the diameter of the injection pipe (12) and the two are coaxially arranged, thereby achieving preliminary mixing of the hydrogen and air in the premixing section (210); The preliminarily mixed gas is passed through the twisting section (211) that converges toward the center of the premixing disk (2), forming a swirl to promote mixing, and the premixed gas is introduced into the combustion chamber for combustion.

8. The combustion method of the premixed swirl combustion head according to claim 7, characterized in that: The twisting section (211) comprises a radial deflection section (2111) and a circumferential deflection section (2112), wherein the radial deflection section (2111) forms an angle of 0-30° with the axis of the premixing disk (2), and the circumferential deflection section (2112) forms an angle of 0-60° with the axis of the premixing disk (2). The gas converges toward the center through the radial deflection section (2111), thereby accelerating the outlet velocity of the premixing disk (2), supporting the flame, reducing adhesion between the flame surface and the premixing disk (2), and avoiding the risk of ablation. When the gas passes through the circumferential deflection section (2112), a swirl flow is formed with an angle of 0-60° with the axis of the premixing disk (2), forming a stable swirl recirculation zone downstream of the premixing disk (2), and stabilizing the flame within the swirl recirculation zone.

9. The combustion method of the premixed swirl combustion head according to claim 8, characterized in that: The air intake disk (1) is provided with a partition (3), and the partition (3) divides the interior of the air intake disk (1) into an inner air intake chamber (31) and an outer air intake chamber (32); the air intake pipe (11) includes an inner air intake pipe (33) and an outer air intake pipe (34), the inner air intake pipe (33) is communicated with the inner air intake chamber (31), and the outer air intake pipe (34) is communicated with the outer air intake chamber (32); the method comprises respectively inputting hydrogen into the inner air intake pipe (33) and the outer air intake pipe (34), so that the hydrogen enters the inner air intake chamber (31) and the outer air intake chamber (32), respectively.

10. The combustion method of the premixed swirl combustion head according to claim 9, characterized in that: The following steps are also included: A portion of the mixed gas of hydrogen and air is output through the flame lifting hole (4) on the premixing disk (2); The hydrogen output from the flame supporting hole (4) is output through a flame supporting pipe (41) on an air inlet disk (1) coaxially arranged with the flame supporting hole (4); the flame supporting pipe (41) extends into the flame supporting hole (4); and the diameter of the flame supporting hole (4) is larger than the diameter of the flame supporting pipe (41).

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