Premixing nozzle and combustor of gas turbine

Abstract

The invention belongs to the technical field of gas turbines, and particularly relates to a gas turbine premixing nozzle and a combustor, the premixing nozzle comprises a swirl vane, a through hole is formed in the swirl vane, and the through hole is communicated with a fuel cavity of the gas turbine premixing nozzle; at least one row of rough belts are further arranged on the rotational flow blades, and the rough belts are pits; at least one row of spray holes are further formed in the rotational flow blades, and the spray holes are communicated with the through holes; a rough element is arranged at the position of the spraying hole, the rough element covers the spraying hole, and a plurality of fuel holes are formed in the rough element. According to the invention, the mixing uniformity of fuel and air can be effectively improved, so that the tempering problem of the nozzle is solved. The nozzle does not need to be replaced, and the use cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbines, and in particular relates to a premixing nozzle and a burner of a gas turbine. Background Art

[0002] For traditional natural gas gas turbines, if the fuel is mixed with hydrogen (because the flame propagation speed of hydrogen is faster than that of methane), during the premixing process, it is easy for the fuel and air to mix unevenly, resulting in a high hydrogen concentration in the boundary layer, local backfire, and burning of the nozzle.

[0003] In engineering, if the fuel is mixed with hydrogen for combustion, the simplest way to prevent flashback is to reduce or block the fuel holes to increase the injection speed of the fuel and make the mixture more uniform. However, in actual operation, when the hydrogen content of the fuel reaches 12%, the nozzle still flashes slightly and the swirler is burned black. Since it is only a local flashback phenomenon and the nozzle as a whole is not burned, it can be judged that at the current hydrogen content, the fuel and air are not fully mixed in the swirler, and at the boundary layer, the laminar velocity in the boundary layer is less than the flame propagation velocity of hydrogen.

[0004] Therefore, when the hydrogen content in the fuel reaches 12%, the fuel and air are unevenly mixed, resulting in flashback. Prior art CN117450543A discloses a gas turbine and its nozzle, the nozzle comprising: a first premixing nozzle; a first air flow channel and a first premixing flow channel sequentially arranged inside the first premixing nozzle; the first air flow channel is used to guide air to the first premixing flow channel; the first premixing flow channel is used to mix air and fuel to form a mixed gas, and is used to guide the mixed gas to the combustion chamber; the inner diameter of the first premixing flow channel decreases along the first direction; a fuel spray rod is used to guide the fuel to the first premixing flow channel. The inner diameter of the first premixing flow channel in the nozzle decreases along the first direction (that is, the flow direction of the mixed gas), so the flow velocity of the mixed gas increases after passing through the first premixing flow channel. In other words, the nozzle can increase the flow velocity of the mixed gas to reduce the probability of flashback in the combustion chamber.

[0005] However, the above-mentioned prior art cannot be applied to the original nozzle, and a new nozzle needs to be replaced, which makes the original nozzle unusable, thereby increasing the cost. Summary of the invention

[0006] In order to solve the above technical problems in the prior art, the present invention provides a gas turbine premixing nozzle and burner, which solves the flashback problem from two aspects: improving the mixing degree of fuel and air and inducing turbulence on the surface of the swirl blades in advance, and can reuse the original nozzle.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] On the one hand, the present invention provides a gas turbine premixing nozzle, comprising a swirl blade, wherein a through hole is arranged inside the swirl blade, and the through hole is connected to the fuel chamber of the gas turbine premixing nozzle; at least one row of rough bands is also arranged on the swirl blade, and the rough bands are pits; at least one row of spray holes is also arranged on the swirl blade, and the spray holes are connected to the through hole; a rough element is arranged at the spray hole, and the rough element covers the spray hole, and a plurality of fuel holes are arranged on the rough element.

[0009] Furthermore, the rough belt is a combination of one or more of circular pits, square pits, and corrugated pits.

[0010] Furthermore, the rough element is a combination of one or more of a hemispherical shape, a triangular prism shape, and a polyhedron shape.

[0011] Furthermore, the roughness element is connected to the swirl blade by welding.

[0012] Furthermore, the number of the fuel holes is at least 5, and at least 5 fuel holes are respectively arranged in 5 directions of the rough element: front, back, left, right and top.

[0013] Furthermore, the rough belt and the rough element are both arranged at the leading edge of the swirl blade, and the rough belt and the rough element are both arranged on both side surfaces of the swirl blade.

[0014] Furthermore, the rough zone is arranged on a side of the rough element close to the leading edge of the swirl blade.

[0015] Furthermore, the gas turbine premixing nozzle further comprises a central cone and a flow guide housing, wherein the flow guide housing is sleeved around the central cone and is coaxially arranged with the central cone; a premixing channel is arranged between the flow guide housing and the central cone;

[0016] The swirl blades are radially arranged between the central cone and the guide casing.

[0017] Furthermore, a fuel cavity is provided in the central cone, and the fuel cavity is communicated with a through hole inside the swirl blade.

[0018] On the other hand, the present invention provides a burner comprising a burner inner tube and a cylindrical combustion chamber, wherein the burner inner tube has the above-mentioned gas turbine premixing nozzle inside; the cylindrical combustion chamber is provided with the burner inner tube on its inlet side so that the premixed gas ejected from the gas turbine premixing nozzle burns to form combustion gas.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The gas turbine premixing nozzle provided by the present invention adds a rough band and a rough element to the leading edge of the swirl blade of the original nozzle. The addition of the rough band can induce the occurrence of turbulence on the surface of the swirl blade in advance. The setting of the rough element increases the contact area between the fuel and the air, which can effectively improve the mixing uniformity of the fuel and the air, thereby solving the flashback problem of the nozzle. On the basis of improving the mixing uniformity of the fuel and the air, the hydrogen content in the fuel can be increased, and there is no need to replace the nozzle. Only structural improvements need to be made on the basis of the original nozzle to reduce the use cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of a gas turbine premixing nozzle according to the first embodiment of the present invention.

[0022] Figure 2 yes Figure 1 A partial enlarged view of point A in the middle.

[0023] Figure 3 It is a schematic diagram of the structure of the rough element in the first embodiment of the present invention.

[0024] Figure 4 2 is a schematic diagram of the structure of the rough element at another angle in the first embodiment of the present invention.

[0025] Description of reference numerals:

[0026] 1. Swirl blades;

[0027] 101, rough band, 102, rough element, 103, fuel hole;

[0028] 2. Fuel chamber, 3. Central cone, 4. Guide shell. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the protection scope of the present invention.

[0030] It should be noted that, unless otherwise specifically stated, the relative arrangements of components and steps, and numerical expressions set forth in these embodiments should not be construed as limiting the scope of the present invention.

[0031] The following description of the exemplary embodiments is merely illustrative and is not intended to limit the present invention and its application or use in any sense. Techniques, methods and devices known to ordinary technicians in the relevant field may not be discussed in detail here, but where applicable, these techniques, methods and devices should be considered as part of this specification.

[0032] Embodiment 1

[0033] This embodiment provides a gas turbine premixing nozzle, such as Figure 1 As shown, it comprises a swirl blade 1, a central cone 3 and a flow guide housing 4, wherein the flow guide housing 4 is sleeved on the periphery of the central cone 3 and is coaxially arranged with the central cone 3; a premixing channel is arranged between the flow guide housing 4 and the central cone 3;

[0034] The swirl blade 1 is radially arranged between the central cone 3 and the guide housing 4. A fuel cavity 2 is arranged in the central cone 3, and the fuel cavity 2 is communicated with a through hole inside the swirl blade 1.

[0035] A through hole is arranged inside the swirl blade 1, and the through hole is connected to the fuel chamber 2 of the gas turbine premixing nozzle; at least one row of rough bands 101 is also arranged on the swirl blade 1, and the rough bands 101 are pits; at least one row of spray holes is also arranged on the swirl blade 1, and the spray holes are connected to the through hole; a rough element 102 is arranged at the spray hole, and the rough element 102 covers the spray hole, and a plurality of fuel holes 103 are arranged on the rough element 102.

[0036] A fuel inlet is arranged on one side of the central cone 3. The fuel enters the fuel chamber 2 from the fuel inlet and then enters the through hole from the bottom of the swirl blade 1, and then is ejected from the fuel hole 103 of the rough element 102 on the surface of the swirl blade 1. Air enters from the inlet of the premixing channel and is fully mixed with the fuel in the premixing channel, and the mixed gas is ignited at the outlet of the nozzle.

[0037] Among them, the rough belt 101 can be entirely circular pits, square pits, or corrugated pits, or a part of it can be circular pits, a part can be square pits, or another part can be corrugated pits. In other embodiments, the rough belt 101 can also be pits of other shapes.

[0038] In this embodiment, the rough belt 101 is entirely circular pits.

[0039] The rough elements 102 may all be in the shape of a hemisphere, a triangular prism, or a polyhedron; or some of the rough elements may be in the shape of a hemisphere, some may be in the shape of a triangular prism, or some may be in the shape of a polyhedron, such as a diamond shape. In other embodiments, the rough elements 102 may also be in other shapes.

[0040] In this embodiment, Figure 3 and Figure 4As shown, the rough element 102 is a hemispherical shell structure, which is welded to the swirl blade 1. At the same time, the number of fuel holes 103 on the surface of the rough element 102 is 5, and the 5 fuel holes 103 are respectively arranged in the 5 directions of the front, back, left, right and top of the rough element 102. In other embodiments, the number of fuel holes 103 can be increased, such as 6, 7, and 8, but as a preferred embodiment, at least one fuel hole 103 is arranged in the 5 directions of the front, back, left, right and top.

[0041] like Figure 2 As shown, the rough belt 101 and the rough element 102 are both arranged at the leading edge of the swirl blade 1 , and the rough belt 101 and the rough element 102 are both arranged on both sides of the swirl blade 1 .

[0042] The rough zone 101 is arranged on a side of the rough element 102 close to the leading edge of the swirl blade 1 .

[0043] Since the rough band 101 is first provided at the leading edge of the swirl blade 1, the air first encounters the rough band 101 before the fuel is ejected from the fuel hole 103, so that the air swirls on the surface of the swirl blade 1 in advance, which is conducive to the subsequent uniform mixing with the fuel. At the same time, the fuel is ejected outward from the five directions of the rough element 102, which increases the contact area between the fuel and the air on the one hand, and increases the turbulence on the other hand, further improving the uniformity of the mixing of the fuel and the air and avoiding the flashback problem.

[0044] In addition, this embodiment is based on the original nozzle, does not change the internal structure of the nozzle, only adds a rough belt and a rough element, which is convenient for maintenance and reduces the cost of transformation.

[0045] Embodiment 2

[0046] The present embodiment provides a burner, comprising a burner inner tube and a cylindrical combustion chamber, wherein the burner inner tube has a gas turbine premixing nozzle provided in the first embodiment inside the burner inner tube; the cylindrical combustion chamber is provided with the burner inner tube at the inlet side thereof, so that the premixed gas ejected from the gas turbine premixing nozzle burns to form combustion gas.

[0047] The above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, a person skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A gas turbine premixing nozzle, comprising a swirl blade, wherein a through hole is arranged inside the swirl blade, and the through hole is connected to a fuel cavity of the gas turbine premixing nozzle; characterized in that: At least one row of rough bands is also arranged on the swirl blade, and the rough bands are pits; at least one row of spray holes is also arranged on the swirl blade, and the spray holes are connected with the through holes; a rough element is arranged at the spray hole, and the rough element covers the spray hole, and a plurality of fuel holes are arranged on the rough element.

2. The gas turbine premixing nozzle according to claim 1, characterized in that: The rough belt is a combination of one or more of circular pits, square pits and corrugated pits.

3. The gas turbine premixing nozzle according to claim 1, characterized in that: The rough element is in the shape of a hemisphere, a triangular prism, a polyhedron or a combination of one or more of the above.

4. The gas turbine premixing nozzle according to claim 1, characterized in that: The rough element is welded to the swirl blade.

5. The gas turbine premixing nozzle according to claim 1, characterized in that: The number of the fuel holes is at least 5, and at least 5 fuel holes are respectively arranged in 5 directions of the rough element, namely, front, back, left, right and top.

6. The gas turbine premixing nozzle according to claim 1, characterized in that: The rough belt and the rough element are both arranged at the leading edge of the swirl blade, and the rough belt and the rough element are both arranged on both sides of the swirl blade.

7. The gas turbine premixing nozzle according to claim 6, characterized in that: The rough zone is arranged on a side of the rough element close to the leading edge of the swirl blade.

8. The gas turbine premixing nozzle according to claim 1, characterized in that: The gas turbine premixing nozzle further comprises a central cone and a flow guide housing, wherein the flow guide housing is sleeved on the periphery of the central cone and is coaxially arranged with the central cone; a premixing channel is arranged between the flow guide housing and the central cone; The swirl blades are radially arranged between the central cone and the guide casing.

9. The gas turbine premixing nozzle according to claim 8, characterized in that: A fuel cavity is arranged in the central cone, and the fuel cavity is communicated with the through hole inside the swirl blade.

10. A burner comprising a burner inner tube and a cylindrical combustion chamber, characterized in that: The burner inner tube has a gas turbine premixing nozzle according to any one of claims 1 to 9 inside it; the burner inner tube is arranged on the inlet side of the tubular combustion chamber so that the premixed gas injected from the gas turbine premixing nozzle is burned to form combustion gas.

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