Premixing nozzle for mixing gas fuel

Abstract

The premixing nozzle comprises a micro mixing unit body (1), the micro mixing unit body (1) comprises an air inlet pipe (11) and a hydrogen injection pipe (12), the air inlet pipe (11) and the hydrogen injection pipe (12) are hollow pipes, the hydrogen injection pipe (12) is arranged on the radial inner side of the air inlet pipe (11), and the hydrogen injection pipe (12) is arranged on the radial inner side of the air inlet pipe (11) in the axial direction (A) of the micro mixing unit body (1). The front end of the air inlet pipe (11) protrudes out of the front end of the hydrogen injection pipe (12), hydrogen injection holes (13) are formed in the front end of the hydrogen injection pipe (12) and comprise the axial hydrogen injection hole (131) and the radial hydrogen injection hole (132), the axial hydrogen injection hole (131) extends in the axial direction of the hydrogen injection pipe (12), and the radial hydrogen injection hole (132) extends in the radial direction of the hydrogen injection pipe (12). The radial hydrogen injection holes (132) extend in the radial direction of the hydrogen injection pipe (12).

Description

Technical Field

[0001] The present application relates to the technical field of combustion nozzles, and in particular to a premixing nozzle for mixing gas fuel. Background Art

[0002] Low-carbon combustion technology is of great significance to the field of power energy. Hydrogen has the advantages of high combustion calorific value and zero carbon emissions. As a low-carbon energy source, hydrogen has broad application prospects in the future. However, compared with conventional hydrocarbon fuels, hydrogen has a fast flame propagation speed, a high adiabatic flame temperature, and differential diffusion characteristics, which can easily cause uneven mixing and cause local "hot spots", which in turn can easily cause flashback and high NO x Problems such as emissions and thermal-acoustic instability pose challenges to the design of the combustion chamber nozzle of the power unit.

[0003] At present, in the field of combustion power, hydrogen-blended fuel has been rapidly developed and gradually applied in the fields of internal combustion engines, ground combustion engines, etc. As the proportion of hydrogen blending increases, the diffusion rate of hydrogen is further expanded, the reaction activity is significantly enhanced, and flashback and high emission problems are prone to occur, which in turn causes burner nozzle ablation and pollutant emissions exceeding the standard.

[0004] There are several methods of hydrogen fuel combustion, which can be divided into large-scale mixed combustion and micro-mixed combustion according to the nozzle diameter.

[0005] Among them, large-scale mixed combustion is the mixed combustion of hydrogen and oxidant within a spatial scale of tens of millimeters. This mixed combustion method eventually forms a large flame combustion zone, which is prone to uneven mixing, long residence time in the high-temperature zone, and high NOx emissions. Large-scale mixed combustion is prone to flashback under hydrogen-rich conditions.

[0006] Patent application CN116066857A discloses a gas turbine combustion nozzle structure and working method, and patent application CN116066858A discloses a low-emission hydrogen fuel micro-mixing combustion chamber for a gas turbine. They both use diffusion combustion, which is prone to high-temperature hot spots and has NO x Disadvantages: High pollutant emissions. Summary of the invention

[0007] The present application aims to propose a premixing nozzle for mixing gaseous fuel, so as to solve the problem of efficient mixing of hydrogen fuel and air and high-performance combustion.

[0008] The present application proposes a premixing nozzle for mixing gaseous fuel, comprising a micro-mixing unit body, wherein the micro-mixing unit body comprises an air intake pipe and a hydrogen injection pipe,

[0009] The air intake pipe and the hydrogen injection pipe are both hollow pipes. The hydrogen injection pipe is arranged radially inward of the air intake pipe. In the axial direction of the micro-hybrid unit, the front end of the air intake pipe protrudes beyond the front end of the hydrogen injection pipe.

[0010] A hydrogen injection hole is disposed at the front end of the hydrogen injection pipe. The hydrogen injection hole includes an axial hydrogen injection hole and a radial hydrogen injection hole. The axial hydrogen injection hole extends along the axial direction of the hydrogen injection pipe, and the radial hydrogen injection hole extends along the radial direction of the hydrogen injection pipe.

[0011] In at least one possible implementation, the hydrogen injection pipe includes a cylindrical section and a conical section, the conical section is located at a front end of the cylindrical section, and the front end of the hydrogen injection pipe is gradually contracted to form the conical section.

[0012] In at least one possible implementation, the radial hydrogen injection holes are disposed in the cylindrical segment.

[0013] In at least one possible implementation, the inner wall surface of the air intake pipe tapers into a cone at the front end.

[0014] In at least one possible embodiment, the premixing nozzle includes a hydrogen injector, an array nozzle, an adapter flange and a mixing distance adjustment member.

[0015] The hydrogen injection pipe is arranged on the hydrogen injector, and the air intake pipe is arranged on the array nozzle. The hydrogen injector and the array nozzle are connected together through the adapter flange and the mixing distance adjusting member. The mixing distance adjusting member can be replaced, and the distance between the front end of the hydrogen injection pipe and the front end of the air intake pipe can be adjusted through the mixing distance adjusting member.

[0016] In at least one possible implementation manner, a distance between a front end of the hydrogen injection pipe and a front end of the air intake pipe is greater than 0 and less than or equal to 40 mm.

[0017] In at least one possible implementation manner, the air intake pipe and the hydrogen injection pipe are coaxially arranged, and one hydrogen injection pipe is arranged in each of the air intake pipes.

[0018] In at least one possible implementation, the end surface of the front end of the premixing nozzle is circular, rectangular or annular.

[0019] In at least one possible implementation, the premixing nozzle has a plurality of micro-mixing units, and the plurality of micro-mixing units are arranged in a rectangular array or in a radial arrangement.

[0020] In at least one possible implementation, the boundary distance between two adjacent micro-hybrid units is 5 mm to 20 mm.

[0021] By adopting the above technical solution, by setting the axial hydrogen injection hole and the radial hydrogen injection hole, the cross jet and the coaxial jet are combined to achieve efficient and uniform mixing of the fuel (hydrogen) and the oxidant, and the premixing effect is better, thereby obtaining a more uniform temperature field, reducing or avoiding the occurrence of local high temperature areas, reducing or avoiding the reactants staying in the high temperature area, thereby reducing NO x emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A cross-sectional view of a premixing nozzle for mixing gaseous fuel according to an embodiment of the present application is shown.

[0023] Figure 2 Shows Figure 1 A partial enlarged view of .

[0024] Figure 3 A schematic structural diagram of a hydrogen injector of a premixing nozzle for mixing gaseous fuel according to an embodiment of the present application is shown.

[0025] Figure 4 A schematic structural diagram of an array nozzle of a premixing nozzle for mixing gaseous fuel according to an embodiment of the present application is shown.

[0026] Figure 5 A front view of an array nozzle of a premixing nozzle for blending gaseous fuel according to an embodiment of the present application is shown.

[0027] Figure 6 A front view of an array nozzle of a premixing nozzle for blending gaseous fuel according to another embodiment of the present application is shown.

[0028] Figure 7 A front view of an array nozzle of a premixing nozzle for blending gaseous fuel according to yet another embodiment of the present application is shown.

[0029] Description of Reference Numerals

[0030] 1 micro-hybrid unit 11 air intake pipe 111 cone 12 hydrogen injection pipe 13 hydrogen injection hole 131 axial hydrogen injection hole 132 radial hydrogen injection hole 14 annular channel

[0031] 2 Hydrogen injector 21 Hydrogen distribution chamber 22 Hydrogen inlet manifold 23 Hydrogen injector mounting flange

[0032] 3 Mixing distance adjustment

[0033] 4 Adapter flange

[0034] 5 array nozzle 51 nozzle outlet 52 array nozzle mounting flange

[0035] A axial direction C circumferential direction R radial direction DETAILED DESCRIPTION

[0036] In order to more clearly explain the above-mentioned purposes, features and advantages of the present application, the specific implementation methods of the present application are described in detail in this section in conjunction with the accompanying drawings. In addition to the various implementation methods described in this section, the present application can also be implemented in other different ways. Without violating the spirit of the present application, those skilled in the art can make corresponding improvements, deformations and substitutions, so the present application is not limited by the specific embodiments disclosed in this section. The scope of protection of the present application shall be subject to the claims.

[0037] like Figures 1 to 7 As shown, the embodiment of the present application proposes a premixing nozzle for mixing gas fuel, which includes a micro-mixing unit body 1, a hydrogen injector 2, a mixing distance adjustment member 3, an adapter flange 4 and an array nozzle 5.

[0038] The micro-hybrid unit 1 includes an air intake pipe 11 and a hydrogen injection pipe 12. Both the air intake pipe 11 and the hydrogen injection pipe 12 are hollow pipes. The hydrogen injection pipe 12 is located radially inside the air intake pipe 11. The air intake pipe 11 and the hydrogen injection pipe 12 are coaxially arranged. In the radial direction R of the micro-hybrid unit 1, an annular channel 14 is formed between the air intake pipe 11 and the hydrogen injection pipe 12, and hydrogen and air can be mixed in the annular channel 14.

[0039] In the axial direction A of the micro-hybrid unit 1, the front end of the air intake pipe 11 ( Figure 1 , Figure 2 The lower end of the hydrogen injection pipe 12 protrudes from the front end ( Figure 1 , Figure 2 The distance between the front end of the hydrogen injection pipe 12 and the front end of the air intake pipe 11 is a mixing distance h, and the mixing distance h may be greater than 0 and less than or equal to 40 mm.

[0040] The hydrogen injection pipe 12 includes a cylindrical section 121 and a conical section 122. The conical section 122 is located at the front end of the cylindrical section 121. The front end of the hydrogen injection pipe 12 gradually contracts to form the conical section 122. The outer wall surface of the conical section 122 can be gradually contracted to form a cone or a truncated cone, thereby avoiding or reducing the possibility of forming a step recirculation zone, shortening the residence time of the premixed gas in the micro-mixing unit, and reducing the probability of spontaneous combustion.

[0041] The rear end of the hydrogen injection pipe 12 ( Figure 1 and Figure 2 The upper end of the chamber is a hydrogen inlet, which can be connected to the hydrogen distribution chamber 21 described later.

[0042] The front end of the hydrogen injection pipe 12 ( Figure 1 and Figure 2 A hydrogen injection hole 13 is provided at the lower end of the housing 100. The hydrogen injection hole 13 may include an axial hydrogen injection hole 131 and a radial hydrogen injection hole 132.

[0043] The axial hydrogen injection hole 131 may extend along the axial direction A of the hydrogen injection pipe 12, and one axial hydrogen injection hole 131 may be provided. The radial hydrogen injection hole 132 may extend along the radial direction R of the hydrogen injection pipe 12, and a plurality of radial hydrogen injection holes 132 (for example, 4) may be provided, and the plurality of radial hydrogen injection holes 132 may be evenly arranged along the circumferential direction C of the hydrogen injection pipe 12.

[0044] Furthermore, the radial hydrogen injection holes 132 are located in the cylindrical section 121 of the hydrogen injection pipe 12 , that is, the radial hydrogen injection holes 132 avoid the conical section 122 of the hydrogen injection pipe 12 .

[0045] Optionally, the air intake pipe 11 may be located only in front of the hydrogen injection pipe 12, so that the air intake pipe 11 can surround a partial area where the hydrogen injection hole 13 is located, and the air intake pipe 11 does not need to surround the entire axial area of ​​the hydrogen injection pipe 12. The hydrogen ejected from the hydrogen injection hole 13 through the hydrogen injection pipe 12 can be mixed with air in the annular channel 14. The axial hydrogen injection hole 131 can form a coaxial jet, and the radial hydrogen injection hole 132 can form a cross jet. The comprehensive mixing of the coaxial jet and the cross jet can more efficiently achieve the mixing of the fuel and the oxidant.

[0046] The diameter of the hydrogen injection hole 13 may be 0.2 mm to 1 mm, and the hydrogen injection hole 13 may be circular, rectangular, elliptical, or the like.

[0047] The air intake pipe 11 may be a hollow circular pipe, and the inner diameter of the air intake pipe 11 may be 4 mm to 10 mm. The hydrogen injection pipe 12 may be a hollow circular pipe, and the outer diameter of the hydrogen injection pipe 12 may be 2 mm to 5 mm.

[0048] like Figures 1 to 3 As shown, the hydrogen injector 2 has a hydrogen distribution chamber 21, which is a cavity capable of accommodating gas, and is connected to a hydrogen injection pipe 12 and a hydrogen inlet manifold 22. A plurality of hydrogen injection pipes 12 may be provided, and the hydrogen injection pipe 12 may be connected to the front end of the hydrogen distribution chamber 21, and the hydrogen inlet manifold 22 may be connected to the rear end and the side of the hydrogen distribution chamber 21. The hydrogen in the hydrogen inlet manifold 22 may be distributed and supplied to a plurality of hydrogen injection pipes 12 through the hydrogen distribution chamber 21.

[0049] The hydrogen injector 2 has a hydrogen injector mounting flange 23 , and the hydrogen injector mounting flange 23 is used to connect to the array nozzle 5 .

[0050] like Figure 1 , Figure 2 and Figure 4 As shown, the array nozzle 5 may be provided with a plurality of nozzle outlets 51, the front end of the air intake pipe 11 may be connected to the nozzle outlet 51 (ie, the air outlet of the micro-hybrid unit), and the rear end of the air intake pipe 11 is an air inlet.

[0051] The inner wall of the air intake pipe 11 tapers to a conical surface 111 at the front end, which can increase the gas velocity at the outlet of the micro-mixing unit and prevent boundary layer flashback. Optionally, the angle formed by the conical surface 111 and the axial direction A of the air intake pipe 11 can be 2 to 10 degrees.

[0052] The array nozzle 5 may be provided with an array nozzle mounting flange 52 , and the array nozzle mounting flange 52 is used for connecting to the hydrogen injector 2 .

[0053] The hydrogen injector 2 is connected to the array nozzle 5 through the mixing distance adjusting member 3 and the adapter flange 4. The mixing distance adjusting member 3 may be in the shape of a U-shaped ...

[0054] like Figures 5 to 7 As shown, the premixing nozzle may include a plurality of micro-mixing units 1, and the plurality of micro-mixing units 1 may be arranged in a rectangular array (see Figure 5 ) or arranged radially (see Figure 6 and Figure 7 ). Premix nozzle head ( Figure 1 The end face of the lower end (in the middle) can be circular, rectangular or annular, etc.

[0055] Reference Figure 5 The end face of the head of the premixing nozzle (array nozzle 5) can be rectangular, and the multiple micro-mixing units 1 can be arranged in a rectangular array. The number of micro-mixing units 1 in each row and column can be determined according to the actual size of the combustion chamber. The multiple micro-mixing units 1 are evenly arranged in the row and column directions to ensure flame stability.

[0056] Reference Figure 6 The end surface of the head of the premixing nozzle (array nozzle 5) may be circular, and the plurality of micro-mixing units 1 may be arranged radially, with the number of micro-mixing units gradually increasing from the radial inner side to the radial outer side. The plurality of micro-mixing units 1 are evenly arranged in the circumferential direction C of the premixing nozzle, and the plurality of micro-mixing units 1 may form 3 to 5 concentric rings (the most central ring may have only one micro-mixing unit 1).

[0057] Reference Figure 7The end surface of the head of the premixing nozzle (array nozzle 5) may be annular, and a plurality of micro-mixing units 1 may be evenly arranged in annular shape in the circumferential direction C of the premixing nozzle. The plurality of micro-mixing units 1 may form 3 to 5 concentric rings.

[0058] The shape of the adapter flange 4 may be the same as the end face shape of the head of the premixing nozzle. For example, the adapter flange 4 may be rectangular, circular or annular.

[0059] It can be understood that the number, arrangement and spacing of the micro-mixing units 1 can be adjusted according to the power, outlet temperature and combustion components of the combustion chamber.

[0060] like Figures 5 to 7 As shown, the boundary distance between two adjacent micro-mixing units 1 is 5 mm to 20 mm, that is, the distance between the edges of two adjacent nozzle outlets 51 is 5 mm to 20 mm. This can not only make the flames compactly distributed, so that the temperature distribution at the combustion chamber outlet is more uniform, but also reduce the interaction between the flames between the nozzle outlets 51 to achieve stable combustion.

[0061] The premixing nozzle for mixing gaseous fuel of the present application can achieve at least one of the following beneficial effects.

[0062] (1) The present application combines the cross jet with the coaxial jet by setting the axial hydrogen injection hole 131 and the radial hydrogen injection hole 132, thereby achieving efficient and uniform mixing of the fuel (hydrogen) and the oxidant. Compared with the traditional large-scale swirl flame stabilization combustion, the premixing effect of the premixing nozzle of the present application is better, and a more uniform temperature field can be obtained, so that the fuel and air are mixed evenly, the local high temperature area is reduced or avoided, and the reactants are reduced or avoided to stay in the high temperature area, thereby reducing NO x emission.

[0063] (2) The vortex breakup process caused by combustion is the main cause of flashback in swirl premixed combustion. The present application disperses the mixing process of fuel (hydrogen) and air to multiple micro-mixing units, reducing the dependence on traditional swirl mixing methods and avoiding flashback caused by the vortex breakup process due to strong swirl.

[0064] The small flames formed by multiple micro-mixing units form a plane flame at the nozzle outlet plane, which effectively shortens the length of the overall flame, does not form a large-scale recirculation zone (the central recirculation zone produced by the traditional swirl burner), and reduces the residence time of the reactants in the high temperature zone, thereby reducing NO x emission.

[0065] (3) Due to the high flow velocity in the microchannel, the probability of boundary layer flashback and turbulent flame propagation flashback is also very low. The use of multiple micro-mixing units can increase heat loss, and the high flow velocity shortens the residence time of the premixed gas in the micro-mixing unit, reducing the probability of spontaneous combustion.

[0066] (4) The present application can adapt to the combustion requirements under different loads by setting different numbers of micro-hybrid units 1 and adjusting the equivalence ratio.

[0067] It should be understood that at least some aspects or features of the above-mentioned implementation modes, embodiments or examples may be appropriately combined.

[0068] It is understood that in the present application, when the number of parts or components is not particularly limited, the number may be one or more, and the multiple here means two or more. For the case where the number of parts or components shown in the drawings and / or described in the specification is a specific number such as two, three, four, etc., the specific number is usually exemplary and not restrictive, and it can be understood as multiple, that is, two or more, but this does not mean that the present application excludes the case of one.

[0069] In the present application, unless otherwise clearly stated or limited, the terms such as "install", "assemble", "assemble", "connect", "connect", "couple", "link", "abut", "connect", "interconnect", "intercommunication", "conduction", "fixation", "fastening" and the like should be understood in a broad sense, for example, they can be direct or indirect. For example, regarding connection, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly stated or limited. For example, regarding connectivity / conduction, it can be direct connectivity / conduction, or it can be indirect connectivity / conduction via an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0070] In the present application, unless otherwise clearly stated or limited, a component disposed on / installed on / located on / accommodated on / placed in, within, inside, etc. another component may be any of the following two situations: a part or most of the one component is located in the other component; and the one component is completely accommodated in the other component.

[0071] Although the present application is described in detail using the above-mentioned embodiments, it is obvious to those skilled in the art that the present application is not limited to the embodiments described in this specification. The present application can be modified and implemented as a modified embodiment without departing from the subject matter and scope of the present application as determined by the claims. Therefore, the description in this specification is for the purpose of illustration and does not have any restrictive meaning for the present application.

Claims

1. A premixing nozzle for mixing gas fuel, characterized in that: The micro-hybrid unit (1) comprises an air intake pipe (11) and a hydrogen injection pipe (12). The air intake pipe (11) and the hydrogen injection pipe (12) are both hollow pipes. The hydrogen injection pipe (12) is arranged radially inside the air intake pipe (11). In the axial direction (A) of the micro-hybrid unit (1), the front end of the air intake pipe (11) protrudes beyond the front end of the hydrogen injection pipe (12). A hydrogen injection hole (13) is provided at the front end of the hydrogen injection pipe (12), and the hydrogen injection hole (13) comprises an axial hydrogen injection hole (131) and a radial hydrogen injection hole (132). The axial hydrogen injection hole (131) extends along the axial direction of the hydrogen injection pipe (12), and the radial hydrogen injection hole (132) extends along the radial direction of the hydrogen injection pipe (12).

2. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The hydrogen injection pipe (12) comprises a cylindrical section (121) and a conical section (122), wherein the conical section (122) is located at the front end of the cylindrical section (121), and the front end of the hydrogen injection pipe (12) is gradually contracted to form the conical section (122).

3. The premixing nozzle for mixing gas fuel according to claim 2, characterized in that: The radial hydrogen injection holes (132) are arranged in the cylindrical section (121).

4. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The inner wall surface of the air intake pipe (11) gradually tapers into a cone at the front end.

5. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The premixing nozzle comprises a hydrogen injector (2), an array nozzle (5), an adapter flange (4) and a mixing distance adjusting member (3). The hydrogen injection pipe (12) is arranged on the hydrogen injector (2), and the air intake pipe (11) is arranged on the array nozzle (5). The hydrogen injector (2) and the array nozzle (5) are connected together via the adapter flange (4) and the mixing distance adjustment member (3). The mixing distance adjustment member (3) can be replaced, and the distance between the front end of the hydrogen injection pipe (12) and the front end of the air intake pipe (11) can be adjusted by the mixing distance adjustment member (3).

6. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The distance between the front end of the hydrogen injection pipe (12) and the front end of the air intake pipe (11) is greater than 0 and less than or equal to 40 mm.

7. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The air intake pipe (11) and the hydrogen injection pipe (12) are coaxially arranged, and one hydrogen injection pipe (12) is arranged in each of the air intake pipes (11).

8. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The end surface of the front end of the premixing nozzle is circular, rectangular or annular.

9. The premixing nozzle for mixing gas fuel according to claim 1, characterized in that: The premixing nozzle comprises a plurality of micro-mixing units (1), and the plurality of micro-mixing units (1) are arranged in a rectangular array or in a radial arrangement.

10. The premixing nozzle for mixing gas fuel according to claim 9, characterized in that: The boundary distance between two adjacent micro-hybrid unit bodies (1) is 5 mm to 20 mm.

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