A gas turbine and its nozzle

Abstract

The application discloses a gas turbine and a nozzle thereof, and relates to the technical field of gas turbines. The nozzle comprises a first nozzle pipe, a fuel flow channel, a fuel cavity and at least one fuel injection hole arranged in the first nozzle pipe, a first premixing flow channel and an air flow channel arranged in the first nozzle pipe, and a nozzle end wall. The fuel flow channel and the fuel cavity are communicated through the fuel injection hole, and the fuel injection hole is directed to the nozzle end wall. The fuel cavity is arranged in the first nozzle pipe, so that the fuel can not only cool the nozzle end wall after entering the nozzle, but also increase the speed of the fuel after absorbing a large amount of heat in the nozzle. The lower temperature of the nozzle end wall and the higher flow rate of the fuel can reduce the probability of backfire in the combustion chamber.

Description

Technical Field

[0001] The present application relates to the technical field of gas turbines, and in particular to a gas turbine and a nozzle thereof. Background Art

[0002] Premixed combustion is one of the most advanced technologies for achieving low emissions in gas turbines. This technique involves partially or fully premixing the fuel with air before it enters the gas turbine's combustion chamber. This reduces the flame temperature during combustion, thereby reducing pollutant emissions. The main method for achieving fuel-air mixing in existing technologies involves rapidly mixing the fuel and air in the nozzle to form a mixture, which is then injected into the combustion chamber for combustion. Existing gas turbine nozzles primarily utilize cylindrical or ribbed nozzles. Upon entering the existing nozzle, the fuel immediately mixes with the air within the nozzle to form a mixture. Because the mixture contains both air and fuel, it can ignite within the nozzle. It is important to understand that the mixture can only produce external work if it burns within the combustion chamber. If the mixture burns within the nozzle, it will flash back. Flashback can easily cause high-temperature erosion of the nozzle or internal combustion chamber components, potentially damaging the gas turbine. Existing premixed nozzles are susceptible to flashback over extended periods of operation as temperatures rise. Summary of the Invention

[0003] The purpose of the present application is to provide a gas turbine and a nozzle thereof to solve the technical problem in the prior art that the premixing nozzle is prone to combustion chamber flashback and ablation.

[0004] To achieve the above objectives, this application provides the following technical solutions:

[0005] In a first aspect, the technical solution of the present application provides a nozzle, which comprises:

[0006] a first nozzle tube, the first nozzle tube comprising a nozzle end wall;

[0007] A fuel flow passage, a fuel cavity and at least one fuel injection hole are provided inside the first nozzle; the fuel flow passage and the fuel cavity are connected through each fuel injection hole, and the fuel injection hole faces the nozzle end wall;

[0008] A first premixing flow channel and an air flow channel are arranged inside the first nozzle; the first premixing flow channel is used to mix fuel and air to form a mixed gas, and is used to guide the mixed gas to the combustion chamber; the first premixing flow channel is connected to the air flow channel, and the first premixing flow channel is connected to the fuel cavity.

[0009] As a specific solution in the technical solution of the present application, a plurality of first through holes and a plurality of second through holes are further provided inside the first nozzle; each first through hole is used to connect the fuel chamber and the first premixing flow channel, and each second through hole is used to connect the air flow channel and the first premixing flow channel.

[0010] As a specific solution in the technical solution of the present application, the axial center lines of the first nozzle, the fuel flow channel, the fuel chamber, the first premixing flow channel and the air flow channel coincide; the first through holes are evenly distributed around the axial center line of the first nozzle; and the second through holes are evenly distributed around the axial center line of the first nozzle.

[0011] As a specific solution in the technical solution of the present application, a cooling cavity is further provided inside the first nozzle, and the cooling cavity is connected to the air flow channel and is used to guide the air to impact the nozzle end wall.

[0012] As a specific solution in the technical solution of the present application, the first nozzle is also provided with a plurality of third through holes and a plurality of cooling nozzles; each third through hole is used to connect the cooling cavity and the air flow channel; each cooling nozzle is used to guide the air in the cooling cavity to the combustion chamber; the axis of the third through hole is parallel to, intersecting with, or not in the same plane as the axis of the cooling nozzle.

[0013] As a specific solution in the technical solution of the present application, the fuel flow channel includes an inlet section flow channel, a contraction section flow channel and an outlet section flow channel arranged in sequence along a first direction; the first direction is parallel to the axis of the first nozzle and points from the head end to the end of the first nozzle; the inner diameter of the contraction section flow channel is smaller than the inner diameters of the inlet section flow channel and the outlet section flow channel.

[0014] As a specific solution in the technical solution of this application, it also includes:

[0015] a second nozzle, sleeved on the outside of the first nozzle; a second premixing flow channel is provided between the second nozzle and the first nozzle; the second premixing flow channel is used to mix fuel and air to form a mixed gas and to guide the mixed gas to the combustion chamber; the second premixing flow channel is in communication with the fuel chamber;

[0016] A plurality of connecting members, one end of each connecting member is connected to the inner wall of the second nozzle, and the other end of each connecting member is connected to the outer wall of the first nozzle.

[0017] As a specific solution in the technical solution of the present application, the connecting part includes a swirl blade; the swirl blade is provided with a swirl chamber, a fourth through hole and a plurality of swirl nozzle holes; the fourth through hole is used to connect the swirl chamber and the fuel chamber; each swirl nozzle hole is used to connect the swirl chamber and the second premixing flow channel.

[0018] As a specific solution of the technical solution of the present application, the fuel chamber includes a first fuel chamber and a second fuel chamber, the fuel flow channel is connected to the first fuel chamber through a fuel nozzle; the swirl chamber is connected to the first fuel chamber through a fourth through hole; the first premixing flow channel is connected to the second fuel chamber through the first through hole;

[0019] The first nozzle is further provided with a connecting through hole and a diffusion nozzle; the connecting through hole is used for connecting the second fuel cavity to the first fuel cavity or the fuel flow channel; the diffusion nozzle is used to guide the fuel in the second fuel cavity to the combustion chamber.

[0020] In a second aspect, the technical solution of the present application proposes a gas turbine comprising a nozzle as described in any one of the first aspects.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The fuel cavity allows the fuel to cool the nozzle tip wall upon entering the nozzle and, after absorbing significant heat from the nozzle, increase its velocity. Lower nozzle tip wall temperatures and higher fuel flow rates both reduce the likelihood of flashback in the combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A three-dimensional diagram of a nozzle proposed in an embodiment of the present application;

[0024] Figure 2 A cross-sectional view of a nozzle proposed in an embodiment of the present application;

[0025] Figure 3 for Figure 2 Schematic diagram of fluid flow in the nozzle;

[0026] Figure 4 A three-dimensional diagram of another nozzle proposed in an embodiment of the present application;

[0027] Figure 5 A cross-sectional view of another nozzle proposed in an embodiment of the present application;

[0028] Figure 6 for Figure 5 Schematic diagram of fluid flow in the nozzle;

[0029] Figure 7 for Figure 5 The nozzle in FIG is a cross-sectional view along line JJ (excluding the second nozzle);

[0030] Figure 8 for Figure 7 A perspective view of the middle nozzle;

[0031] Figure 9 A cross-sectional view of another nozzle proposed in an embodiment of the present application;

[0032] Figure 10 This is a cross-sectional view of another nozzle proposed in an embodiment of the present application.

[0033] In the figure: 1. first nozzle; 11. fuel flow channel; 111. inlet section flow channel; 112. contraction section flow channel; 113. outlet section flow channel; 114. fuel nozzle hole; 115. connecting rod; 12. first fuel chamber; 121. first through hole; 122. fourth through hole; 13. first premixing flow channel; 131. second through hole; 132. end nozzle hole; 14. air flow channel; 141. cooling chamber; 142. third through hole; 143. cooling nozzle hole; 15. nozzle end wall; 16. second fuel chamber; 161. connecting through hole; 162. diffusion nozzle hole; 2. second nozzle; 21. second premixing flow channel; 3. connecting piece; 31. swirl chamber; 32. swirl nozzle hole; 321. suction side nozzle hole; 322. pressure side nozzle hole; 323. mid-chord area nozzle hole; 324. trailing edge area nozzle hole. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] It should be noted that, in the description of this application, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on this application.

[0036] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0037] It should be noted that like numbers and letters represent similar items in the following figures, so once an item is defined or described in one figure, it will not need to be further discussed and described in detail in the description of the subsequent figures.

[0038] Before understanding the embodiments of this application, it is important to understand that, as the background art indicates, premixed combustion technology involves pre-forming a mixture of fuel and air within a nozzle before the fuel and air enter the combustion chamber. This mixture is then fed into the combustion chamber for combustion. The operating principle of a gas turbine is that the mixture burns in the combustion chamber to produce high-temperature combustion gas. This high-temperature combustion gas drives the turbine to rotate at high speed, which in turn converts the chemical energy of the fuel into mechanical energy to produce external work. It is easy to understand that because the mixture contains both fuel and air, it is capable of combustion. During gas turbine operation, improper control of the mixture supply can cause combustion in the nozzle. Those skilled in the art refer to this combustion phenomenon in the nozzle as "combustion chamber flashback." Combustion chamber flashback can, at best, result in energy loss, resulting in lower gas turbine efficiency; at worst, it can cause high-temperature erosion of the nozzle or other components in the combustion chamber, reducing the service life of the gas turbine.

[0039] It's important to note that flashback in a gas turbine's combustion chamber is closely related to the mixture's ejection velocity and the nozzle's temperature. Slower mixture ejection velocity increases the likelihood of flashback; faster mixture ejection velocity reduces the likelihood of flashback. Generally, as the mixture is ejected from the nozzle orifices 15 of the nozzle, the higher the temperature of the nozzle's end wall 15, the easier it is for the mixture inside the nozzle to ignite, leading to a higher probability of flashback.

[0040] It should be understood that the reason why "premixing nozzles in the prior art are prone to combustion chamber flashback" as stated in the background technology of this application is that the high temperature of the premixing nozzle can ignite the mixture inside the nozzle, causing combustion chamber flashback.

[0041] In order to solve the technical problems in the background technology, the present application provides a nozzle, specifically, Figures 1 to 10 As shown, the nozzle includes a first nozzle 1, and the first nozzle 1 includes a nozzle end wall 15. Specifically, in the embodiment of the present application, Figure 1 、 Figure 2 、 Figure 4 and Figure 5 It can be seen that the nozzle end wall 15 refers to the end wall of the nozzle end. In the embodiment of the present application, the components or structures used to guide the fluid in the nozzle (for example: the first nozzle 1, the fuel flow channel 11 or the second premixing flow channel 21, etc.) are defined as the head end and the tail end, wherein the head end refers to the end where the fluid flows into the component or structure, and the tail end refers to the end where the fluid flows out of the component or structure. That is to say, in the nozzle proposed in the embodiment of the present application, Figure 3 and Figure 6As shown in FIG, the flow direction of the fluid is always from the head end to the end end of a component or structure. In order to clearly show the flow path of each fluid to those skilled in the art, Figure 3 and Figure 6 Light blue lines are used to identify the flow paths of various fluids. In the embodiments of the present application, the fluid refers to air, fuel, or a mixture formed by mixing air and fuel.

[0042] Specifically, in this embodiment, the interior of the first nozzle 1 is further provided with a fuel flow channel 11, a fuel cavity and at least one fuel injection hole 114. The fuel flow channel 11 and the fuel cavity are connected through each fuel injection hole 114, and the fuel injection hole 114 faces the nozzle end wall 15. In this embodiment, the fuel cavity may only include Figure 2 and Figure 5 The first fuel chamber 12 shown; may also include Figure 9 and Figure 10 As shown, a first fuel cavity 12 and a second fuel cavity 16 .

[0043] In this embodiment, the fuel flow channel 11 is used to input fuel into the combustion chamber. Specifically, the fuel flow path in the fuel flow channel 11 is as follows: Figure 3 As shown by route A in FIG. It should be understood that the temperature of the fuel in the fuel flow channel 11 is generally close to room temperature (i.e., approximately 25°C), while the temperature of the high-temperature combustion gas in the combustion chamber generally exceeds 1000°C. The nozzle end wall 15 is closest to the combustion chamber in the entire nozzle, meaning that the temperature of the nozzle end wall 15 is also close to 1000°C. Because each fuel nozzle hole 114 faces the nozzle end wall 15, the fuel in the fuel flow channel 11 can impact the nozzle end wall 15 through each fuel nozzle hole 114 during its entry into the fuel cavity. It is easy to understand that the lower temperature fuel directly impacting the nozzle end wall 15 significantly lowers the temperature of the nozzle end wall 15, thereby reducing the risk of flashback in the combustion chamber. Furthermore, by impacting the nozzle end wall 15, the fuel's temperature increases and its density decreases. Under the same mass conditions, its flow velocity increases. This means that during the subsequent formation of the mixture, the temperature and velocity of the mixture can be increased, thereby reducing the risk of flashback in the combustion chamber. As described in the background art, in the prior art, since there is no first fuel cavity 12 structure, low-temperature fuel is directly sprayed from the fuel flow channel 11 into the premixing flow channel or the combustion chamber, which easily causes backfire in the combustion chamber and reduces the efficiency of the gas turbine.

[0044] In this embodiment, in order to form a mixed gas inside the nozzle, the combustion chamber can form premixed combustion and reduce the emission of pollutants. Figure 2 and Figure 5As shown, the interior of the first nozzle 1 is further provided with a first premixing channel 13 and an air channel 14. The air channel 14 is used to introduce air into the interior of the nozzle. The first premixing channel 13 is used to mix fuel and air to form a mixed gas, and is used to guide the mixed gas to the combustion chamber. The first premixing channel 13 is connected to the air channel 14, and the first premixing channel 13 is connected to the fuel chamber.

[0045] In the embodiment of the present application, the air flow path in the air flow channel 14 is as follows: Figure 3 As shown in the route B in FIG. Since the first premixing channel 13 is connected to both the air channel 14 and the fuel cavity, Figure 3 As shown, the air in the air flow channel 14 can enter the first premixing channel 13 along a route E, and the fuel in the fuel chamber can enter the first premixing channel 13 along a route C. Specifically, the fuel and air entering the first premixing channel 13 can mix to form a mixed gas, which is then injected into the combustion chamber through the terminal nozzle 132.

[0046] In the embodiments of the present application, the terminal nozzle hole 132 can be a hole of any shape, without any restrictions. For example, the terminal nozzle hole 132 can be a straight hole, that is, the axis of the terminal nozzle hole 132 is parallel to the axis of the first nozzle 1. To ensure uniform mixing of the air and fuel in the first premixing flow channel 13, the terminal nozzle hole 132 can also be an inclined hole. Multiple inclined terminal nozzle holes 132 facilitate the formation of a swirl in the ejected mixture, and a swirling mixture facilitates mixing. It is easy to understand that the higher the uniformity of the mixture mixing, the fewer pollutants are generated during the combustion process of the mixture.

[0047] In the embodiments of the present application, any method can be used to connect two cavities (for example, the fuel cavity and the first premixing channel 13, the air channel 14 and the first premixing channel 13, the first premixing channel 13 and the combustion chamber, etc. in this embodiment) without any limitation. For example, the two cavities can be connected through a pipe (not shown in the figure) or a hole, which will not be described in detail later. In one embodiment of the present application, in order to reduce the difficulty of processing and reduce the processing cost, such as Figure 2 and Figure 5 As shown, the two cavities are subsequently connected through holes (e.g., the first through hole 121, the second through hole 131, the third through hole 142, the fuel nozzle 114, the cooling nozzle 143, and the terminal nozzle 132, etc.). In the embodiment of the present application, there is no limitation on the number of the above-mentioned holes, which can be one or more and can be set according to actual needs during application.

[0048] In the embodiment of the present application, in order to enable the fluid flowing out of the holes (e.g., the first through hole 121, the second through hole 131, and the terminal nozzle hole 132, etc.) to form a swirl flow, the axis of the hole can form an angle of 45° to 60° with the axis of the first nozzle 1 to cause the fluid to swirl and improve the uniformity of the air and fuel mixing. This will not be described in detail below.

[0049] In order to make the air and fuel in the first premixing flow channel 13 be evenly mixed to form a mixed gas. In one embodiment of the present application, Figure 2 and Figure 5 As shown, the interior of the first nozzle 1 is further provided with a plurality of first through-holes 121 and a plurality of second through-holes 131. Each first through-hole 121 is used to connect the fuel chamber and the first premixing channel 13, and each second through-hole 131 is used to connect the air channel 14 and the first premixing channel 13. Multiple fuel sprays are formed through the multiple first through-holes 121, and multiple air sprays are formed through the multiple second through-holes 131. These multiple fuel sprays and multiple air sprays can be evenly mixed in the first premixing channel 13.

[0050] In order to further improve the uniformity of the mixed gas formed in the first premixing channel 13. In one embodiment of the present application, Figure 2 and Figure 5 As shown, the axis lines of the first nozzle 1, the fuel flow channel 11, the fuel cavity, the first premixing flow channel 13 and the air flow channel 14 coincide with each other. The first through holes 121 are evenly distributed around the axis line of the first nozzle 1 (that is, the axis line of the first premixing flow channel 13); the second through holes 131 are evenly distributed around the axis line of the first nozzle 1. It should be understood that since the first through holes 121 and the second through holes 131 are evenly distributed around the axis line of the first premixing flow channel 13, the air and fuel injected into the first premixing flow channel 13 can be evenly distributed around the circumference of the first premixing flow channel 13. In other words, the air and fuel in the first premixing flow channel 13 can be mixed to form a more uniform mixture.

[0051] It should be clear that if Figure 3 As shown, the air outside the nozzle enters the air flow channel 14 along the route B. In this embodiment, all the air in the air flow channel 14 can be input into the first premixing flow channel 13 through the second through hole 131 along the route E. However, in order to use the air to cool the portion of the nozzle end wall 15 that is not impacted by the fuel, as shown in FIG. Figure 2 As shown, a plurality of cooling holes 143 are provided on the portion of the nozzle end wall 15 that is not impacted by the fuel. Each cooling hole 143 can be connected to the air flow channel 14. Figure 3As shown, air entering the air flow channel 14 can be split into two streams. One stream flows along route E and enters the first premixing channel 13. The other stream flows along route F and is ejected into the combustion chamber through cooling holes 143 formed in the nozzle end wall 15 to participate in combustion. It will be readily understood that in a gas turbine, the air temperature is approximately 300°C to 500°C, which is much lower than that of the nozzle end wall 15. Therefore, the air ejected from the cooling holes 143 can cool the portion of the nozzle end wall 15 that is not impacted by the fuel.

[0052] In order to improve the cooling effect of the air on the nozzle end wall 15, as described above, Figure 2 As shown, the first nozzle 1 is further provided with a cooling chamber 141, which is connected to the air flow channel 14 and is used to guide air to impact the nozzle end wall 15. It is easy to understand that the provision of the cooling chamber 141 can reduce the velocity of air ejected from the cooling nozzle holes 143, that is, it can increase the residence time of the air in the cooling chamber 141. In other words, if the residence time of the air in the cooling chamber 141 is increased, the heat exchange time between the air and the nozzle end wall 15 is increased, and the cooling effect of the air on the nozzle end wall 15 is improved.

[0053] In the embodiment of the present application, any structure can be used to guide the air in the cooling chamber 141 to impact the nozzle end wall 15 to improve the cooling effect. For example, a wire mesh structure can be set in the cooling chamber 141 to increase the contact area between the air and the nozzle end wall 15, thereby improving the cooling effect; Figure 2 and Figure 5 As shown, the first nozzle 1 is further provided with a plurality of third through holes 142 and a plurality of cooling nozzle holes 143. Each third through hole 142 is used to connect the cooling cavity 141 with the air flow channel 14; each cooling nozzle hole 143 is used to guide air in the cooling cavity 141 to the combustion chamber. The axis of the third through hole 142 is parallel to, intersecting with, or not aligned with the axis of the cooling nozzle hole 143.

[0054] Specifically, the axis of the third through hole 142 is parallel to, intersecting with, or not in the same plane as the axis of the cooling nozzle 143. In other words, the axis of the third through hole 142 and the axis of the cooling nozzle 143 must not coincide. It is easy to understand that after the fluid passes through the hole, the flow direction of the fluid will be parallel to the axis of the hole. Figure 2 and Figure 5 As shown, air first enters the cooling cavity 141 through the third through-hole 142 before being ejected from the cooling cavity 141 through the cooling nozzle holes 143. Because the axis of the third through-hole 142 and the axis of the cooling nozzle holes 143 do not coincide, the air entering the cooling cavity 141 through the third through-hole 142 is guaranteed to impact the nozzle end wall 15. This structure reduces the air flow velocity and increases the air's residence time in the cooling cavity 141, thereby improving the cooling effect.

[0055] It should be noted that, as previously mentioned, if the flow velocity of the mixture fluctuates, flashback is more likely to occur in the combustion chamber. It's easy to understand that the mixture is formed by the combination of air and fuel. That is, if the flow velocities of either air or fuel remain constant, the flow velocity of the mixture will also not fluctuate. During gas turbine operation, since air comes from the compressor, it essentially does not fluctuate. During gas turbine operation, the fuel supply must be adjusted to control the turbine's power. In other words, fluctuations in the flow velocity of the mixture are caused by fluctuations in the flow velocity of the fuel.

[0056] In one embodiment of the present application, in order to reduce the fluctuation of the flow velocity of the fuel. Figure 2 and Figure 5 As shown, the fuel flow channel 11 includes an inlet section flow channel 111, a contraction section flow channel 112, and an outlet section flow channel 113, arranged in sequence along a first direction. The first direction is parallel to the axis of the first nozzle 1 and points from the head end to the tail end of the first nozzle 1. The inner diameter of the contraction section flow channel 112 is smaller than the inner diameters of the inlet section flow channel 111 and the outlet section flow channel 113.

[0057] Specifically, the provision of the smaller inner diameter converging section flow channel 112 results in a relatively larger cross-sectional area for both the first fuel chamber 12 and the outlet section flow channel 113 compared to the preceding section. It should be noted that during fluid flow, if the cross-sectional area of ​​the flow path increases, the static pressure of the fluid increases. If the static pressure of the fluid increases, the pressure differential across the orifice (i.e., the fuel nozzle orifice 114 or the first through-hole 121) increases. It is easy to understand that an increase in the pressure differential across the orifice can reduce fluctuations caused by flow instability during fluid flow in the flow channel. In other words, it can increase the flow stability of the subsequently formed mixture. It should also be noted that an increase in the pressure differential across the orifice also increases the velocity of the fluid jetting through the orifice. The increased velocity of the fuel ejected from the fuel nozzle orifice 114 facilitates the impact of the fuel on the nozzle end wall 15, thereby cooling the nozzle end wall 15 and increasing the temperature of the fuel. The increased velocity of the fuel ejected from the first through-hole 121 facilitates the mixing of the fuel and air in the first premixing channel 13.

[0058] In the embodiment of the present application, in order to improve the stability between the fuel flow channel 11 and the first fuel cavity 12, it is also possible to Figure 2 As shown, a plurality of connecting rods 115 are provided inside the first nozzle 1. Specifically, one end of the connecting rod 115 is connected to the inner wall forming the first fuel cavity 12, and the other end of the connecting rod 115 is connected to the outer wall forming the fuel flow channel 11.

[0059] It should be understood that the amount of mixed gas generated by a gas turbine needs to be changed accordingly during power changes. For example, if the power of the gas turbine decreases, the amount of mixed gas generated needs to be reduced; if the power of the gas turbine increases, the amount of mixed gas generated needs to be increased. It is easy to understand that in the embodiment of the present application, the mixed gas is mainly formed by mixing the air and fuel in the first premixing flow channel 13. Since the flow channel area of ​​the first premixing flow channel 13 is fixed, if the amount of mixed gas is to be increased, the flow rate of the mixed gas needs to be increased, that is, the supply pressure of the air or fuel needs to be increased; if the amount of mixed gas is to be reduced, the flow rate of the mixed gas needs to be reduced, that is, the supply pressure of the air or fuel needs to be reduced. It should be clear that, as can be seen from the foregoing, if the flow rate of the mixture is reduced during the stable operation of the gas turbine, combustion chamber backfire is likely to occur; if only the fuel supply pressure is reduced, and the air supply pressure is not reduced to maintain the flow rate of the mixture, it is likely to cause the proportion of fuel in the mixture to be small, causing the gas turbine to stall; if only the air supply pressure is reduced, and the fuel supply pressure is not reduced to maintain the flow rate of the mixture, it is likely to cause the proportion of fuel in the mixture to be large, causing an increase in pollutants produced by combustion.

[0060] In order to reduce the occurrence of combustion chamber flashback during the power change of the gas turbine and maintain the low pollutant emission performance of the gas turbine, in one embodiment of the present application, Figure 5 As shown, the nozzle also includes a second nozzle 2 and multiple connectors 3. The second nozzle 2 is sleeved on the outside of the first nozzle 1. A second premixing channel 21 is provided between the second nozzle 2 and the first nozzle 1, and the second premixing channel 21 is connected to the fuel chamber. It is easy to understand that the second premixing channel 21 has a similar function to the first premixing channel 13 mentioned above, and is mainly used to form a mixture of air and fuel inside it and guide the mixture into the combustion chamber for combustion. In this embodiment, one end of each connector 3 is connected to the inner wall of the second nozzle 2, and the other end of each connector 3 is connected to the outer wall of the first nozzle 1. The function of the connector 3 is to ensure a stable connection between the first nozzle 1 and the second nozzle 2, that is, to ensure that the second premixing channel 21 is stable. In the embodiments of this application, there is no limitation on the position of each connector 3. For example, each connector 3 can be randomly distributed, or each connector 3 can be evenly distributed around the circumference of the first nozzle 1.

[0061] Specifically, in this embodiment, if the power of the gas turbine increases, the second premixing passage 21 can be used to mix and form a mixed gas, thereby increasing the amount of the mixed gas produced. If the power of the gas turbine decreases, the amount of the mixed gas mixed and formed in the second premixing passage 21 can be reduced. Compared to the prior art method of changing the total amount of the mixed gas by changing the flow rate of the mixed gas in the first premixing passage 13, the embodiment of the present application can maintain the flow rate and composition of the mixed gas in the first premixing passage 13 unchanged. In other words, the embodiment of the present application can both reduce the occurrence of combustion chamber flashback and maintain the low pollutant emission performance of the gas turbine.

[0062] It should be clear that in the embodiments of the present application, Figure 6 As shown, the air outside the nozzle can enter the second premixing channel 21 along the route H. It is easy to understand that if a mixed gas is to be formed in the second premixing channel 21, fuel needs to be introduced into the second premixing channel 21. In the embodiment of the present application, the fuel can be introduced into the second premixing channel 21 through a pipeline, or as shown in FIG. Figure 7 and Figure 8 As shown, the fuel is introduced into the second premixing channel 21 by means of the connecting piece 3. Specifically, as Figure 7 As shown, the connecting member 3 is provided with a swirl chamber 31, a fourth through hole 122 and a plurality of swirl nozzles 32. Among them, the fourth through hole 122 is used to connect the swirl chamber 31 and the fuel chamber; each swirl nozzle 32 is used to connect the swirl chamber 31 and the second premixing channel 21.

[0063] When using, Figure 6 As shown, the fuel in the fuel cavity (i.e., the first fuel cavity 12) can enter the swirl cavity 31 through the fourth through hole 122; the fuel in the swirl cavity 31 can enter the second premixing flow channel 21 through the swirl nozzle 32. Specifically, the path of the fuel from the fuel cavity into the second premixing flow channel 21 is as follows: Figure 6 Route G is shown.

[0064] In the embodiment of the present application, there is no limitation on the shape and structure of the connector 3. For example, it can be block-shaped or rod-shaped. In order to improve the mixing uniformity of air and fuel in the second premixing flow channel 21, in a specific embodiment of the present application, Figure 8 As shown, the connecting member 3 can be a swirl vane. Specifically, the swirl vane can form a swirl in the gap located in the second premixing channel 21, which is conducive to uniform mixing of air and fuel. It is easy to understand that in the embodiment of the present application, in order to improve the uniformity of mixing of air and fuel in the first premixing channel 13, a swirler (not shown in the figure) composed of multiple swirl vanes can also be provided in the first premixing channel 13.

[0065] It should be clear that in the channel with swirl blades (that is, the second premixing channel 21), the flow field has significant non-uniformity. Specifically, the fluid velocity is low and the pressure is high at the pressure surface of the swirl blade, and the fluid velocity is high and the pressure is low at the suction surface of the swirl blade. Therefore, when designing the swirl nozzle 32, taking this non-uniformity into consideration, the swirl nozzle 32 can be specially designed to increase the uniformity of the fuel and air mixing and reduce the mixing loss. In order to further improve the uniformity of the air and fuel mixing in the second premixing channel 21. After many verifications, such as Figure 8 As shown, the swirl nozzles 32 include: a suction-side nozzle 321 located on the suction side of the swirl blade; a pressure-side nozzle 322 located on the pressure side of the swirl blade; a mid-chord nozzle 323 located in the mid-chord region of the swirl blade; and a trailing-edge nozzle 324 located in the trailing-edge region of the swirl blade. The arrangement of these multiple nozzles effectively improves the uniformity of fuel and air mixing.

[0066] It should be noted that the combustion stability of premixed combustion is lower than that of diffusion combustion. Specifically, diffusion combustion refers to the phenomenon that the fuel is not mixed with the air in advance, and after being ejected from the nozzle, it diffuses and mixes with the air at the nozzle while burning. In the embodiment of the present application, in order to improve the stability of nozzle combustion, Figure 9 and Figure 10 As shown, the fuel chamber includes a first fuel chamber 12 and a second fuel chamber 16. The fuel flow channel 11 is connected to the first fuel chamber 12 through the fuel nozzle 114. The swirl chamber 31 is connected to the first fuel chamber 12 through the fourth through hole 122. The first premixing flow channel 13 is connected to the second fuel chamber 16 through the first through hole 121.

[0067] Specifically, the first nozzle 1 is further provided with a connecting through hole 161 and a diffusion nozzle 162. The connecting through hole 161 is used for Figure 9 As shown, the second fuel chamber 16 and the first fuel chamber 12 are connected; or the connecting through hole 161 is used as shown. Figure 10 The nozzle 16 connects the second fuel chamber 16 and the fuel flow channel 11. The diffusion nozzle 162 is used to guide the fuel in the second fuel chamber 16 to the combustion chamber. When the nozzle is in use, some of the fuel in the fuel flow channel 11 or the first fuel chamber 12 can enter the second fuel chamber 16 through the connecting hole 161. The fuel is then ejected from the second fuel chamber 16 through the diffusion nozzle 162 and into the combustion chamber, resulting in diffusion combustion. This improves the combustion stability of this embodiment of the nozzle.

[0068] It should be noted that the nozzles proposed in the embodiments of this application, through the provision of a fuel cavity, not only cool the nozzle tip wall upon entering the nozzle, but also increase their velocity after absorbing a large amount of heat from within the nozzle. Both lower nozzle tip wall temperature and higher fuel flow rates can reduce the probability of flashback in the combustion chamber.

[0069] After introducing the nozzle proposed in the embodiment of the present application, the gas turbine proposed in the embodiment of the present application is introduced below. Specifically, the gas turbine includes the nozzle as in any one of the above embodiments.

[0070] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0071] It should be noted that the gas turbine disclosed in the embodiments of this application has a nozzle with a fuel cavity. Upon entering the fuel cavity, the fuel not only cools the nozzle tip wall but also increases its velocity after absorbing a significant amount of heat from within the nozzle. Both lower nozzle tip wall temperature and higher fuel flow rates can reduce the probability of flashback in the combustion chamber.

[0072] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A nozzle, characterized in that: include: A first nozzle (1), the first nozzle (1) comprising a nozzle end wall (15); A fuel flow channel (11), a fuel cavity, and at least one fuel injection hole (114) are provided inside the first nozzle (1); the fuel flow channel (11) and the fuel cavity are connected through each fuel injection hole (114), and the fuel injection hole (114) faces the nozzle end wall (15); A first premixing channel (13) and an air channel (14) are provided inside the first nozzle (1); the first premixing channel (13) is used to mix fuel and air to form a mixed gas, and is used to guide the mixed gas to a combustion chamber; the first premixing channel (13) is connected to the air channel (14), and the first premixing channel (13) is connected to the fuel cavity; the axis center lines of the first nozzle (1), the fuel channel (11), the fuel cavity, the first premixing channel (13) and the air channel (14) coincide with each other; A second nozzle (2) is sleeved on the outside of the first nozzle (1); a second premixing flow channel (21) is provided between the second nozzle (2) and the first nozzle (1); the second premixing flow channel (21) is used to mix fuel and air to form a mixed gas, and is used to guide the mixed gas to the combustion chamber; the second premixing flow channel (21) is connected to the fuel cavity; A plurality of connecting members (3), one end of each connecting member (3) is connected to the inner wall of the second nozzle (2), and the other end of each connecting member (3) is connected to the outer wall of the first nozzle (1); the connecting member (3) includes a swirl blade; the swirl blade is provided with a swirl chamber (31), a fourth through hole (122) and a plurality of swirl nozzle holes (32); the fourth through hole (122) is used to connect the swirl chamber (31) and the fuel chamber; each swirl nozzle hole (32) is used to connect the swirl chamber (31) and the second premixing flow channel (21); the fuel chamber includes a first fuel chamber (12) and a second fuel chamber (16); the fuel flow channel (11) is connected to the first fuel chamber (12) through the fuel nozzle hole (114); the swirl chamber (31) is connected to the first fuel chamber (12) through the fourth through hole (122); the first premixing flow channel (13) is connected to the second fuel chamber (16) through the first through hole (121); The first nozzle (1) is further provided with a connecting through hole (161) and a diffusion nozzle hole (162); the connecting through hole (161) is used for connecting the second fuel cavity (16) to the first fuel cavity (12) or the fuel flow channel (11); and the diffusion nozzle hole (162) is used for guiding the fuel in the second fuel cavity (16) to the combustion chamber.

2. The nozzle according to claim 1, characterized in that The first nozzle (1) is further provided with a plurality of first through holes (121) and a plurality of second through holes (131); each first through hole (121) is used to connect the fuel cavity and the first premixing flow channel (13), and each second through hole (131) is used to connect the air flow channel (14) and the first premixing flow channel (13).

3. The nozzle according to claim 2, characterized in that The first through holes (121) are evenly distributed around the axis of the first nozzle (1); and the second through holes (131) are evenly distributed around the axis of the first nozzle (1).

4. The nozzle according to any one of claims 1 to 3, characterized in that A cooling cavity (141) is further provided inside the first nozzle (1), the cooling cavity (141) being in communication with the air flow channel (14) and being used to guide air to impact the nozzle end wall (15).

5. The nozzle according to claim 4, characterized in that The first nozzle (1) is further provided with a plurality of third through holes (142) and a plurality of cooling spray holes (143); each third through hole (142) is used to connect the cooling cavity (141) and the air flow channel (14); each cooling spray hole (143) is used to guide the air in the cooling cavity (141) to the combustion chamber; the axis of the third through hole (142) is parallel to, intersecting with, or not in the same plane as the axis of the cooling spray hole (143).

6. The nozzle according to any one of claims 1 to 3, characterized in that The fuel flow channel (11) comprises an inlet section flow channel (111), a contraction section flow channel (112), and an outlet section flow channel (113) arranged in sequence along a first direction; the first direction is parallel to the axis of the first nozzle (1) and points from the head end to the tail end of the first nozzle (1); the inner diameter of the contraction section flow channel (112) is smaller than the inner diameters of the inlet section flow channel (111) and the outlet section flow channel (113).

7. A gas turbine, characterized in that: Comprising a nozzle as claimed in any one of claims 1 to 6.

Images