A swirl nozzle suitable for gas turbine combustion chamber

Abstract

The present invention discloses a swirl nozzle suitable for a gas turbine combustion chamber, comprising a diffusion air intake chamber, a diffusion fuel intake chamber, a nozzle cover, a premixed swirl assembly, a diffusion swirl assembly and a purge rod. Premixed air is injected into the nozzle from an air hole on the nozzle cover located upstream of the swirl blades, and premixed fuel is injected into the nozzle from a fuel hole on the nozzle cover located upstream of the swirl blades. The premixed air is premixed upstream of the swirl blades, a swirl is formed through the swirl blades, and the premixed fuel is further premixed in the premixing channel and injected into the combustion chamber to form a flow field condition suitable for premixed combustion. The present invention replaces the fuel holes on the surface of the swirl blades of the nozzle of the in-service gas turbine combustion chamber with the fuel holes located upstream of the nozzle swirl blades, so that the premixed air and premixed fuel are premixed upstream of the nozzle swirl blades, so that the fuel and air are mixed more evenly, and the NO in the combustion chamber is effectively reduced. X It can also avoid the formation of a fuel-rich zone on the swirl blades and reduce swirl blade ablation failures.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbines, and in particular relates to a swirl nozzle suitable for a combustion chamber of a gas turbine. Background Art

[0002] As a highly efficient energy conversion device, gas turbines are widely used in the industrial field. NO generated by high temperature flames in the gas turbine combustion chamber X If no control measures are taken, the concentration of NO in gas turbine combustion chambers will generally reach 200 ppm, exceeding the environmental protection regulations of most industrialized countries, which will seriously harm the atmospheric environment and human health. X The use of dry lean premixed combustion (DLN) can fully premix the fuel with a large amount of air before it enters the combustion chamber, and reasonably control the air and fuel equivalence ratio in the main combustion zone, which can reduce the temperature of the main combustion zone of the combustion chamber, thereby achieving NO X Emission control.

[0003] At present, most gas turbines in service use DLN swirl nozzles to achieve dry lean premixed combustion. The swirl nozzles mainly include nozzle cover, nozzle center body, nozzle swirl blades, etc. The nozzle cover, nozzle center body and swirl blades form an annular channel. Compressed air enters the annular channel from the upstream of the nozzle and flows in the annular channel. Premixing and diffusion fuel channels are provided inside the nozzle center body. A premixing fuel cavity is provided inside the swirl blade, which is connected to the premixing fuel supply channel inside the nozzle center body. Fuel holes are provided on the surface of the swirl blade and are connected to the premixing fuel cavity. The premixed fuel is injected into the premixing fuel cavity of the swirl blade through the premixing fuel channel of the nozzle center body, and is injected into the annular cavity through the fuel holes on the surface of the swirl blade. It is premixed with compressed air in the premixing section downstream of the swirl blade, and then injected into the combustion chamber for combustion. The diffusion fuel is injected into the combustion chamber through the diffusion swirl channel at the head of the center body through the channel inside the diffusion nozzle center body.

[0004] The swirl nozzles in the combustion chambers of in-service gas turbines have the following problems: 1) During the premixed combustion process, air and fuel are mainly mixed in the premixing section downstream of the swirl blades, and then enter the flame tube of the combustion chamber for combustion. The length of the fuel and air mixing is short and the premixing effect is not ideal; 2) When the fuel is ejected from the fuel hole, it tends to flow along the wall of the swirl blade. The contact area between the fuel and air is small, which is not conducive to the mixing of the fuel and air. There is a phenomenon of low uniformity in the mixing of the fuel and air, which can easily lead to local hot spots in the combustion chamber and cause high pollutant emissions in the combustion chamber; 3) The fuel hole is close to the surface of the swirl blade, and a high-concentration fuel belt centered on the fuel hole is easily formed on the surface of the swirl blade. When flashback occurs in the combustion chamber, it is easy to form a fire on the surface of the swirl blade and burn the swirl nozzle. Summary of the invention

[0005] In order to solve the problem of low fuel and air mixing uniformity in the combustion chamber of the in-service gas turbine, NO X In order to solve the problems of high emission, easy flashback and hanging fire, the present invention proposes a swirl nozzle suitable for the combustion chamber of a gas turbine, wherein the swirl nozzle is provided with a premixing fuel hole and an air hole on the outside of the nozzle cover and upstream of the swirl blade. When the combustion chamber of the gas turbine is running, the premixed fuel is directly supplied to the premixing channel inside the swirl nozzle from the fuel hole, and is preliminarily mixed with the compressed air upstream of the swirl blade. The preliminarily premixed gas is then swirled through the swirl blade and further mixed in the premixing channel. The present invention can increase the mixing distance and mixing time of the fuel and air, enhance the mixing uniformity of the fuel and air, reduce the combustion chamber, and avoid the phenomenon of rich fuel area on the swirl blade and hanging fire when the swirl blade flashes back in the combustion chamber.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A swirl nozzle suitable for a gas turbine combustion chamber, comprising a diffusion air inlet cavity, a diffusion fuel inlet cavity, a nozzle cover, a premixed swirl assembly, a diffusion swirl assembly and a purge rod; wherein the diffusion air inlet cavity, the diffusion fuel inlet cavity and the nozzle cover are connected in sequence, and the diffusion air inlet cavity has a diffusion air inlet hole, the diffusion fuel inlet cavity has a diffusion fuel inlet hole, and the nozzle cover has a premixed swirl air inlet hole and a premixed fuel inlet hole; the premixed swirl assembly is located inside the nozzle cover, connected to the diffusion fuel inlet cavity, and The premixed swirl component is provided with swirl blades; the diffusion fuel inlet cavity, the premixed swirl component and the nozzle cover together constitute the premixed swirl channel; the diffusion swirl component is located inside the premixed swirl component, connected to the diffusion air inlet cavity, and the diffusion swirl component is provided with a diffusion swirl channel; the diffusion fuel inlet cavity, the diffusion swirl component and the premixed swirl component together constitute the diffusion fuel channel; the purge rod is located inside the diffusion swirl component, connected to the diffusion fuel inlet cavity; the diffusion air inlet cavity, the purge rod and the diffusion swirl component together constitute the diffusion air channel.

[0008] A further improvement of the present invention is that the premixed fuel and the premixed air can be mixed in the premixed swirl channel and injected into the combustion chamber.

[0009] A further improvement of the present invention is that the diffusion fuel can be injected into the combustion chamber through the diffusion swirl channel to mix with the air injected into the combustion chamber and burn.

[0010] A further improvement of the present invention is that the diffusion air can be injected into the combustion chamber through the diffusion swirl channel to mix with the diffusion fuel injected into the combustion chamber and burn.

[0011] A further improvement of the present invention is that the diffused air inlet hole is provided at the center of the diffused air end cover of the diffused air inlet cavity.

[0012] A further improvement of the present invention is that the diffusion fuel inlet hole is arranged downstream of the diffusion air inlet hole and upstream of the swirl vane.

[0013] A further improvement of the present invention is that a premixed air collecting cavity and a premixed fuel collecting cavity are respectively provided at the connection between the premixed swirl air inlet hole, the premixed fuel inlet hole and the nozzle cover to ensure uniform intake of premixed air and premixed fuel.

[0014] A further improvement of the present invention is that the premixed swirl air inlet holes and the premixed fuel inlet holes on the swirl nozzle cover are evenly distributed along the tangent direction of the circumference of the nozzle cover.

[0015] A further improvement of the present invention is that a diffusion fuel collecting cavity is provided at the connection between the diffusion fuel inlet hole and the diffusion fuel inlet cavity to ensure uniform diffusion fuel intake.

[0016] A further improvement of the present invention is that when the combustion chamber performs diffusion combustion, the diffusion air is injected into the nozzle through the diffusion air inlet hole on the diffusion air inlet cavity, and after being rectified by the air expansion channel, it is ejected into the combustion chamber flame tube through the nozzle diffusion swirl channel outlet; the diffusion fuel is injected into the nozzle through the diffusion fuel inlet hole on the diffusion fuel inlet cavity, and after being rectified by the diffusion fuel channel, it is ejected into the combustion chamber flame tube through the diffusion swirl channel;

[0017] When premixed combustion is carried out in the combustion chamber, premixed air is injected into the nozzle through the air holes on the nozzle cover, and premixed fuel is injected into the nozzle through the fuel holes on the nozzle cover. The premixed air and premixed fuel are initially premixed in the space upstream of the swirl vanes, and after forming a swirl through the swirl vanes on the premixing swirl assembly, they are further mixed in the premixing channel downstream of the swirl vanes and injected into the combustion chamber for combustion.

[0018] The present invention has at least the following beneficial technical effects:

[0019] The swirl nozzle suitable for the combustion chamber of a gas turbine is provided by the present invention. The premixed fuel cavity inside the swirl blades of the nozzle and the fuel holes on the surface of the swirl blades are eliminated, and the fuel holes on the surface of the swirl blades of the nozzle of the combustion chamber of the gas turbine in service are replaced by the fuel holes located upstream of the swirl blades of the nozzle; the premixed fuel is mainly injected into the nozzle by the premixed fuel nozzle located upstream of the swirl blades of the nozzle, preliminarily premixed with the air upstream of the swirl blades, and swirl is formed through the swirl blades, and premixed again in the premixing section of the nozzle. Compared with the original nozzle, the mixing time and distance of the premixed air and the premixed fuel are increased, the mixing degree of air and fuel is increased, the fuel and air are mixed more evenly, and the local high concentration and hot spots in the combustion chamber can be effectively reduced, causing NO XThe emission is higher; in addition, by adopting the scheme provided in the present invention, the fuel and air are initially mixed upstream of the swirl blades, avoiding the phenomenon that the fuel flows close to the wall of the swirl blades and produces a rich fuel belt on the swirl blades, and effectively reducing the burning of the swirl blades in the combustion chamber when a backfire failure occurs in the combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0021] Figure 2 It is a cross-sectional view of the swirl nozzle of the present invention along the X direction.

[0022] Figure 3 It is a cross-sectional view of the swirl nozzle of the present invention along the Y direction.

[0023] Description of reference numerals:

[0024] 1 diffusion air inlet cavity; 1-1 diffusion air end cover; 1-2 diffusion air inlet hole; 2 diffusion fuel inlet cavity; 2-1 diffusion fuel end cover; 2-2 diffusion fuel inlet hole; 3 nozzle cover; 3-1 premixed swirl air inlet hole; 3-2 premixed fuel inlet hole; 3-3 nozzle housing; 3-4 premixed air collecting cavity; 3-5 premixed fuel collecting cavity; 4 premixed swirl assembly; 4-1 swirl blade; 5 diffusion swirl assembly; 6 purge rod. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the present invention is not limited to these embodiments.

[0026] The application field of the present invention is gas turbine swirl nozzles. Figures 1 to 3 As shown, the present invention provides a swirl nozzle suitable for a gas turbine, comprising a nozzle diffusion air inlet cavity 1, a diffusion fuel inlet cavity 2, a nozzle cover 3, a premixing swirl component 4, a diffusion swirl component 5 and a purge rod 6.

[0027] During operation, the diffused air is injected into the nozzle through the diffused air inlet hole 1-2 on the diffused air inlet chamber 1, and is injected into the combustion chamber through the diffused air channel composed of the diffused air inlet chamber 1, the diffused swirl component 5 and the purge rod 6, and is mixed with the diffused fuel and burned; the diffused fuel is injected into the nozzle through the diffused fuel inlet hole 2-2 on the diffused fuel inlet chamber 2, and is injected into the combustion chamber through the diffused fuel channel composed of the diffused fuel inlet chamber 2, the diffused swirl component 5 and the premixed swirl component 4, and is mixed with the diffused air and the premixed air to form a flow field condition suitable for diffusion combustion; the premixed air is injected into the nozzle through the premixed swirl air inlet hole 3-1 on the nozzle cover 3, is mixed with the premixed fuel in the premixed channel composed of the nozzle cover 3 and the premixed swirl component 4, and is injected into the combustion chamber for combustion; the premixed fuel is injected into the nozzle through the premixed fuel inlet hole 3-2 on the nozzle cover 3, is mixed with the premixed air in the premixed channel composed of the nozzle cover 3 and the premixed swirl component 4, and is injected into the combustion chamber to form a flow field condition suitable for premixed combustion.

[0028] Preferably, the diffusion air inlet hole 1 - 2 is opened at the center of the diffusion air end cover 1 - 1 of the diffusion air inlet cavity 1 .

[0029] Preferably, the diffusion fuel inlet hole 2-2 is arranged downstream of the diffusion air inlet hole 1-2 and upstream of the swirl blade 4-1, which can ensure that the premixed fuel and premixed air are mixed before passing through the swirl blade 4-1 and avoid the accumulation of premixed fuel in the swirl channel.

[0030] Preferably, a premixed air collecting cavity 3-4 and a premixed fuel collecting cavity 3-5 are respectively provided at the connection between the premixed swirl air inlet hole 3-1, the premixed fuel inlet hole 3-2 and the nozzle outer cover 3 to ensure uniform intake of premixed air and premixed fuel.

[0031] A diffusion fuel collecting cavity is provided at the connection between the diffusion fuel inlet hole 2-2 and the diffusion fuel inlet cavity 2 to ensure uniform diffusion fuel intake.

[0032] Preferably, a plurality of diffusion fuel inlet holes 2-2 may be evenly distributed along the circumference of the diffusion fuel end cover 2-1, thereby reducing the diffusion fuel flow resistance while ensuring the diffusion fuel flow rate.

[0033] Preferably, a plurality of diffusion fuel inlet holes 2-2 may be arranged tangentially along the circumference of the diffusion fuel end cover 2-1, so as to form a pre-swirl flow before the fuel enters the diffusion fuel inlet passage, thereby increasing the turbulence of the diffusion fuel and promoting mixing between the diffusion fuel and air.

[0034] Preferably, a plurality of premixed swirl air inlet holes 3-1 may be evenly arranged along the circumference of the nozzle housing 3-3 to increase the turbulence of the premixed air and the premixed fuel and further enhance the mixing between the premixed air and the premixed fuel.

[0035] Preferably, a plurality of premixed swirl air inlet holes 3-1 may be evenly arranged tangentially along the circumference of the nozzle housing 3-3, so as to form a premixed flow before the premixed air enters the premixed air inlet passage, thereby increasing the turbulence of the premixed air and promoting mixing between the premixed air and the premixed fuel.

[0036] Preferably, a plurality of premix fuel inlet holes 3-2 may be evenly arranged along the circumference of the nozzle housing 3-3, thereby reducing the flow resistance of the premix fuel while ensuring the flow rate of the premix fuel.

[0037] Preferably, a plurality of premixed fuel inlet holes 3-2 may be evenly arranged tangentially along the circumference of the nozzle housing 3-3, so as to form a pre-swirl flow before the premixed fuel enters the premixed fuel inlet passage, thereby increasing the turbulence of the premixed fuel and promoting mixing between the premixed fuel and the premixed air.

[0038] Example

[0039] like Figure 1 As shown, when the gas turbine swirl nozzle is working, the diffused air is injected into the nozzle through the air hole on the diffused air inlet cavity 1, and is injected into the combustion chamber through the diffused air channel composed of the diffused air inlet cavity 1, the diffused swirl component 5 and the purge rod 6, and is mixed with the diffused fuel and burned; the diffused fuel is injected into the nozzle through the diffused fuel inlet hole 2-2 on the diffused fuel inlet cavity 2, and is injected into the combustion chamber through the diffused fuel channel composed of the diffused fuel inlet cavity 2, the diffused swirl component 5 and the premixed swirl component 4, and is mixed with the diffused air and the premixed air to form a flow field condition suitable for diffusion combustion; the premixed air is injected into the nozzle through the premixed swirl air inlet hole 3-1 on the nozzle outer cover 3, mixed with the premixed fuel in the premixed channel composed of the nozzle outer cover 3 and the premixed swirl component 4, and injected into the combustion chamber for combustion; the premixed fuel is injected into the nozzle through the premixed fuel inlet hole 3-2 on the nozzle outer cover 3, mixed with the premixed air in the premixed channel composed of the nozzle outer cover 3 and the premixed swirl component 4, and injected into the combustion chamber to form a flow field condition suitable for premixed combustion.

[0040] Preferably, six diffusion fuel inlet holes 2-2 can be evenly distributed tangentially along the circumference of the diffusion fuel end cover 2-1, which can reduce the flow resistance of the diffusion fuel while ensuring the flow rate of the diffusion fuel, and form a pre-swirl flow before the fuel enters the diffusion fuel inlet channel, thereby increasing the turbulence of the diffusion fuel and promoting the mixing between the diffusion fuel and air.

[0041] Preferably, six premixed swirl air inlet holes 3-1 can be evenly distributed tangentially along the circumference of the nozzle housing 3-3, which can reduce the flow resistance of the premixed air while ensuring the premixed air flow rate, and form a premixed flow before the premixed air enters the premixed air inlet channel to increase the turbulence of the premixed air and promote the mixing between the premixed air and the premixed fuel.

[0042] Preferably, six premixed fuel inlet holes 3-2 can be evenly distributed tangentially along the circumference of the nozzle housing 3-3, which can reduce the flow resistance of the premixed fuel while ensuring the premixed fuel flow rate, and can form a pre-swirl flow before the premixed fuel enters the premixed fuel inlet channel to increase the turbulence of the premixed fuel and promote the mixing between the premixed fuel and the premixed air.

[0043] Preferably, a premixed air collecting cavity is arranged between the premixed swirl air inlet hole 3-1 and the nozzle shell 3-3, and a premixed fuel collecting cavity can be arranged between the premixed fuel inlet hole 3-2 and the nozzle shell 3-3, which can ensure that the premixed air and fuel are uniformly injected into the premixing channel.

Claims

1. A swirl nozzle suitable for a gas turbine combustion chamber, characterized in that: It comprises a diffusion air intake chamber (1), a diffusion fuel intake chamber (2), a nozzle cover (3), a premixing swirl assembly (4), a diffusion swirl assembly (5) and a purge rod (6); wherein: The diffusion air intake chamber (1), the diffusion fuel intake chamber (2) and the nozzle cover (3) are connected in sequence, and the diffusion air intake chamber (1) has a diffusion air intake hole (1-2), the diffusion fuel intake chamber (2) has a diffusion fuel intake hole (2-2), and the nozzle cover (3) has a premixed swirl air intake hole (3-1) and a premixed fuel intake hole (3-2); the premixed swirl assembly (4) is located inside the nozzle cover (3) and is connected to the diffusion fuel intake chamber (2), and the premixed swirl assembly (4) has a swirl blade (4-1); the diffusion fuel intake chamber (2), the premixed swirl assembly (4) has a swirl blade (4-1) The flow assembly (4) and the nozzle cover (3) together form a premixing swirl channel; the diffusion swirl assembly (5) is located inside the premixing swirl assembly (4) and is connected to the diffusion air intake chamber (1), and the diffusion swirl assembly (5) has a diffusion swirl channel; the diffusion fuel intake chamber (2), the diffusion swirl assembly (5) and the premixing swirl assembly (4) together form a diffusion fuel channel; the purge rod (6) is located inside the diffusion swirl assembly (5) and is connected to the diffusion fuel intake chamber (2); the diffusion air intake chamber (1), the purge rod (6) and the diffusion swirl assembly (5) together form a diffusion air channel.

2. A swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: The premixed fuel and the premixed air can be mixed in the premixed swirl channel and injected into the combustion chamber.

3. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: The diffusion fuel can be injected into the combustion chamber through the diffusion swirl channel to mix with the air injected into the combustion chamber and burn.

4. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: The diffusion air can be injected into the combustion chamber through the diffusion swirl channel to mix with the diffusion fuel injected into the combustion chamber and burn.

5. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: The diffusion air inlet hole (1-2) is arranged at the center of the diffusion air end cover (1-1) of the diffusion air inlet cavity (1).

6. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: The diffusion fuel inlet hole (2-2) is arranged downstream of the diffusion air inlet hole (1-2) and upstream of the swirl blade (4-1).

7. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: A premixed air collecting cavity (3-4) and a premixed fuel collecting cavity (3-5) are respectively arranged at the connection points between the premixed swirl air inlet hole (3-1), the premixed fuel inlet hole (3-2) and the nozzle cover (3) to ensure uniform intake of premixed air and premixed fuel.

8. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: The premixed swirl air inlet holes (3-1) and the premixed fuel inlet holes (3-2) located on the swirl nozzle outer cover (3) are evenly distributed along the tangent direction of the circumference of the nozzle outer cover (3).

9. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: A diffusion fuel collecting cavity is provided at the connection between the diffusion fuel inlet hole (2-2) and the diffusion fuel inlet cavity (2) to ensure uniform diffusion fuel inlet.

10. The swirl nozzle suitable for a gas turbine combustion chamber according to claim 1, characterized in that: When diffusion combustion is carried out in the combustion chamber, diffusion air is injected into the nozzle through the diffusion air inlet hole (1-2) on the diffusion air inlet cavity (1), and after being rectified through the air diffusion channel, it is ejected from the nozzle diffusion swirl channel outlet into the combustion chamber flame tube; The diffusion fuel is injected into the nozzle through the diffusion fuel inlet hole (2-2) on the diffusion fuel inlet cavity (2), and after being rectified by the diffusion fuel channel, it is sprayed into the flame tube of the combustion chamber through the diffusion swirl channel; When premixed combustion is carried out in the combustion chamber, premixed air is injected into the nozzle through the air holes on the nozzle cover (3), and premixed fuel is injected into the nozzle through the fuel holes on the nozzle cover (3). The premixed air and premixed fuel are preliminarily premixed in the space upstream of the swirl blade (4-1), and after forming a swirl flow through the swirl blade (4-1) on the premixed swirl assembly (4), they are further mixed in the premixing channel downstream of the swirl blade (4-1) and injected into the combustion chamber for combustion.

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