Combustion chamber head structure of gas turbine and combustion chamber

Abstract

The utility model relates to a combustion chamber head structure of a gas turbine and a combustion chamber, the combustion chamber head structure comprises a middle shell, an end shell, a pore plate, a plurality of fuel nozzles, an igniter and a flame detector, the fuel nozzles are double-channel staged fuel nozzles, and the igniter is a fuel-rich premixing igniter; the combustion chamber comprises the combustion chamber head structure of the gas turbine. The burner further comprises a fuel collecting pipe set, a flame tube and a sleeve. The double-channel staged fuel nozzles and the fuel-rich premixing igniters which are obliquely arranged are adopted, and the use performance of the combustion chamber is guaranteed by controlling internal flow field distribution of the combustion chamber, excess air coefficient of the head of the combustion chamber and fuel distribution.

Description

Technical Field

[0001] The utility model relates to the technical field of gas turbines, in particular to a combustion chamber head structure and a combustion chamber of a gas turbine. Background Art

[0002] The combustion chamber is one of the important components of the gas turbine. Its function is to convert the chemical energy in the fuel into heat energy through chemical reaction combustion. There are many factors that affect the working performance of the combustion chamber, including the combustion chamber structure, the mixing of fuel and air, and the air-fuel ratio of the combustion chamber. The combustion chamber is in a high temperature and high pressure environment for a long time due to the combustion of fuel. When the field inside the combustion chamber fluctuates, it is easy to have local over-temperature, ablation of combustion chamber components, and oscillation flameout. Not only does it affect the service life of the combustion chamber, but it also makes the gas turbine unable to work normally.

[0003] The Chinese utility model patent with the authorization announcement number CN 215765212 U discloses "a combustion chamber structure of a gas turbine", including a shell, an orifice plate, a premixing swirl nozzle, an igniter, a flame detector and a flame tube; the shell is composed of a head shell and a sleeve, and the orifice plate is arranged between the head shell and the sleeve, dividing the internal space of the combustion chamber into a combustion chamber head area and a flame tube area; a plurality of premixing swirl nozzles are arranged on one side of the orifice plate in the combustion chamber head area, an igniter is arranged on one side of the orifice plate in the flame tube area, and a plurality of air jet holes are also arranged on the orifice plate; the flame tube is arranged in the sleeve, the flame detector is arranged in the middle of the flame tube, and the outlet of the igniter and the measuring point of the flame detector are both arranged in the flame tube area; the sleeve and the flame tube are arranged coaxially with the orifice plate, an annular channel is left between the flame tube and the sleeve, and two rows of mixing holes are arranged axially on the flame tube. The combustion chamber structure can reduce the emission of pollutants on the basis of ensuring stable combustion of the combustion chamber and safety of the combustion chamber wall. However, in this combustion chamber structure, multiple premixed swirl nozzles are arranged parallel to the axis of the combustion chamber, resulting in poor flame concentration in the ignition area, affecting the ignition success rate; in addition, the flow fields between the premixed swirl nozzles are prone to interfere with each other, resulting in poor overall stability of the combustion chamber flow field; it uses a conventional igniter, which also needs to be improved if the ignition success rate needs to be improved.

[0004] The combustion inside the combustion chamber is in a dynamic state when it is working. The combustion inside the combustion chamber will cause problems such as unstable combustion and excessive NOx emissions due to unreasonable matching of factors such as flow field temperature, pressure and fuel component mixing degree. In severe cases, flameout, head flashback erosion, and hot component damage may occur. In order to ensure that the combustion chamber can work normally under various working conditions, it is necessary to analyze and improve the factors affecting the operation of the combustion chamber one by one. Among them, the combustion chamber head structure is the main component that controls the flow field, air-fuel ratio, fuel distribution, and fuel mixing effect of the main combustion area, and requires precise design. Summary of the invention

[0005] The utility model provides a gas turbine combustion chamber head structure and a combustion chamber, which adopt an inclined double-channel staged fuel nozzle and a rich-burn premixed igniter, and ensure the service performance of the combustion chamber by controlling the internal flow field distribution of the combustion chamber, the excess air coefficient at the head of the combustion chamber, and the fuel distribution.

[0006] In order to achieve the above object, the utility model is realized by adopting the following technical solutions:

[0007] A gas turbine combustion chamber head structure includes a combustion chamber head composed of a middle shell, an end shell, an orifice plate, a plurality of fuel nozzles, an igniter and a flame detector; the fuel nozzle is a double-channel staged fuel nozzle, and the igniter is a rich-burn premixed igniter; one open end of the middle shell is detachably connected to the end shell, and an orifice plate is provided at the other open end of the middle shell; the double-channel staged fuel nozzle is composed of a fuel channel and a nozzle body, the fuel channel is installed in the fuel channel installation holes uniformly opened along the circumferential direction of the middle shell, the nozzle body is inclined along the radial direction of the middle shell, the axis of the nozzle body forms an angle of 3° to 10° with the axis of the middle shell, and the injection end faces the center of the middle shell; the orifice plate is provided with nozzle installation holes at the places where the double-response nozzle bodies pass through; the orifice plate is also provided with an igniter installation hole, a flame detector installation hole and a plurality of cooling holes; the rich-burn premixed igniter is arranged between two double-channel staged fuel nozzles and is inclined along the radial direction of the middle shell, its ignition end faces the center of the middle shell, and both ends of the rich-burn premixed igniter are respectively fixed in the end shell and the igniter installation hole; the flame detector is arranged along the axis of the middle shell, and both ends of the flame detector are respectively fixed in the end shell and the flame detector installation hole; the cooling holes are densely distributed around each nozzle installation hole, igniter installation hole and flame detector installation hole.

[0008] Further, the double-channel staged fuel nozzle is composed of a fuel supply pipe, a housing, a swirler and a central body, and is internally provided with a premixing channel, the cross-sectional area of the premixing channel gradually decreases from inside to outside, and the cross-sectional contraction ratio is 0.6 to 0.8; the central body is internally provided with a gas cavity and an air cavity.

[0009] Further, the number of the double-channel staged fuel nozzles is 4.

[0010] Further, the rich-burn premixed igniter is composed of a spark plug and an ignition channel, the spark plug is arranged at one end of the ignition channel, and the ignition channel is provided with a gas-air mixture intake interface at the end close to the spark plug, and the gas-air mixture intake interface is arranged tangentially along the ignition channel.

[0011] Further, the radial angle between the axis of the rich-burn premixed igniter and the axis of the middle shell is 5° to 7°.

[0012] A gas turbine combustor includes the head structure of the gas turbine combustor; it also includes a fuel manifold group, a flame tube, and a sleeve; the fuel output end of the fuel manifold group is connected to the fuel input end of each dual-channel staged fuel nozzle; one end of the flame tube is connected to one end of the middle housing provided with an orifice plate, the sleeve and the flame tube are coaxially arranged with the orifice plate, and an annular channel is left between the flame tube and the sleeve.

[0013] Further, the fuel manifold group is composed of a premixed fuel manifold one, a premixed fuel manifold two, and a diffusion fuel manifold; the premixed fuel manifold one, the premixed fuel manifold two, and the diffusion fuel manifold are all annular manifolds, and are spaced apart by a support frame at the outer end of the combustor head away from the flame tube; the premixed channel in the dual-channel staged fuel nozzle is connected to the premixed fuel manifold one or the premixed fuel manifold two through a premixed fuel pipeline, and the gas cavity in the dual-channel staged fuel nozzle is connected to the diffusion fuel manifold through a pilot fuel pipeline.

[0014] Further, there are 4 dual-channel staged fuel nozzles, with 2 cross-opposite ones as a group. The premixed channel in the first group of dual-channel staged fuel nozzles is connected to the premixed fuel manifold one through a premixed fuel pipeline, and the premixed channel in the second group of dual-channel staged fuel nozzles is connected to the premixed fuel manifold two through a premixed fuel pipeline.

[0015] Further, the flame tube has a laminated annulus structure, that is, it is composed of a plurality of conical flame tube sheets laminated together. There is a gap between two adjacent flame tube sheets. A plurality of wall cooling holes and several thermal expansion grooves are arranged circumferentially on each flame tube sheet; there is also a row of main combustion holes and a row of mixing holes spaced apart on the flame tube, dividing the inside of the flame tube along the flame injection direction into a main combustion zone, a primary mixing zone, and a secondary mixing zone.

[0016] Further, the number of wall cooling holes on the flame tube sheet corresponding to the main combustion zone > the number of wall cooling holes on the flame tube sheet corresponding to the primary mixing zone > the number of wall cooling holes on the flame tube sheet corresponding to the secondary mixing zone.

[0017] Compared with the prior art, the beneficial effects of the present utility model are:

[0018] 1) Multiple fuel nozzles are all arranged at a certain angle with respect to the axis of the combustor and the injection ends face the center of the combustor, which can form a flame concentration area, thereby effectively improving the ignition success rate;

[0019] 2) Multiple dual-channel staged fuel nozzles are arranged at the head of the combustion chamber for combined jet injection, with high flow field stability, which can reduce the probability of nozzle flashback; cooling holes are arranged around each nozzle on the orifice plate, which can form a jet air film outside the combustion flame surface in the main combustion zone, reducing the mutual interference of the flow fields between nozzles, forming a main combustion zone with stable recirculation at the outlet of each nozzle, and no recirculation and reheating will occur at the outlet position of the flame detector, avoiding damage caused by high temperature;

[0020] 3) By using the structural design of the combustion chamber head, the flame tube and the sleeve, the primary air and secondary air of the combustion chamber are distributed (the air distribution directly affects the internal flow field of the combustion chamber); among them, the primary air enters the combustion chamber head to form the main combustion zone air, and the air-fuel ratio in the main combustion zone is limited not to exceed 1.8; the air-fuel ratio and fuel distribution of the nozzle are controlled by using the combustion chamber head structure;

[0021] 4) A rich-burn premixed igniter is arranged in the combustion chamber head structure, including a spark plug and an ignition channel, and is equipped with a corresponding gas-air mixture intake interface. Before ignition, the fuel in the igniter and the compressed air at the outlet of the compressor are premixed with an air-fuel ratio of 0.8 - 1.2, and then the premixed fuel with low speed and low pressure and sufficient mixing is sent into the ignition channel of the igniter and ignited by the spark plug. Since the air flow for spark plug ignition is fully mixed and the flow field stability is high, the ignition success rate can be effectively guaranteed; the igniter has an angle with the axis of the combustion chamber head, forming a short sword-shaped flame at the center position of the main combustion zone of the combustion chamber to ignite the mixed flow field at the nozzle outlet. The premixed air flow in the igniter is in a micro-swirl state, and a gas film is formed at the wall of the igniter, which can protect the wall of the igniter;

[0022] 5) The combustion chamber head realizes the speed increase of the head flow field through the convergent premixing channels in each dual-channel staged fuel nozzle, and prevents backflow, simplifies the combustion chamber structure, reduces the length of the combustion chamber, and makes its structure more compact. Description of the Drawings

[0023] Figure 1 is the front view of the head structure of a gas turbine combustion chamber according to the present utility model.

[0024] Figure 2 is Figure 1 the side view of

[0025] Figure 3 is the structural schematic diagram of the dual-channel staged fuel nozzle according to the present utility model.

[0026] Figure 4 is the structural schematic diagram of the rich-burn premixed igniter according to the present utility model.

[0027] Figure 5 is the swirl streamline diagram of the rich-burn premixed igniter according to the present utility model.

[0028] Figure 6 It is a schematic structural diagram of the orifice plate described in the present utility model.

[0029] Figure 7 It is a schematic structural diagram of the combustion chamber described in the present utility model.

[0030] Figure 8 It is a schematic diagram of the internal flow field of the combustion chamber described in the present utility model.

[0031] Figure 9 It is a schematic diagram of a partial structure of the flame tube described in the present utility model.

[0032] In the figure: 1 - flame detector; 2 - support frame; 3 - combustion chamber head; 4 - flame tube; 5 - sleeve; 6 - diffused fuel manifold; 7 - premixed fuel manifold I; 8 - premixed fuel manifold II; 9 - pilot fuel pipeline; 10 - premixed fuel pipeline; 11 - rich-burn premixed igniter; 12 - dual-channel staged fuel nozzle; 13 - end housing; 14 - orifice plate; 15 - middle housing; 16 - secondary mixing zone; 17 - primary mixing zone; 18 - main combustion zone; 19 - second region; 20 - first region; 21. fuel supply pipe; 22 - third region; 23 - flame tube sheet; 24 - mixing hole; 25 - main combustion hole; 26 - gas chamber; 27 - air chamber; 28 - igniter mounting hole; 29 - nozzle mounting hole; 30 - cooling hole; 31 - flame detector mounting hole; 32 - premixed channel; 33 - fuel jet hole; 34 - swirl vane; 35 - wall cooling hole; 36 - thermal expansion groove; 37 - spark plug; 38 - ignition channel; 39 - gas-air mixture intake interface. Specific embodiments

[0033] The following further describes the specific embodiments of the present utility model in conjunction with the accompanying drawings:

[0034] The present utility model relates to a combustion chamber head structure of a gas turbine and a gas turbine combustion chamber having this structure, aiming to ensure the combustion stability of the combustion chamber, the safe operation of the combustion chamber head, and the NOx emission at the combustion chamber outlet meeting the national standard requirements. To achieve the above combustion chamber performance indicators, the combustion chamber head structure and the combustion chamber described in the present utility model have the functions of controlling the air-fuel ratio in the main combustion zone of the combustion chamber, controlling the staged fuel supply, ignition, and flame monitoring.

[0035] Such as Figure 7As shown in the figure, a gas turbine combustor of the present utility model mainly consists of the following parts: a fuel manifold group, a combustor head 3, a flame tube 4, and a sleeve 5. The fuel manifold group includes a pilot fuel pipeline 9, a diffusion fuel manifold 6, a premixed fuel manifold I 7, a premixed fuel manifold II 8, and a premixed fuel pipeline 10. The diffusion fuel manifold 6, the premixed fuel manifold I 7, and the premixed fuel manifold II 8 are arranged in a circular ring around the periphery of the combustor head 3, and the fuel of each manifold is supplied separately.

[0036] As Figure 1 , Figure 2 shown in the figure, the combustor head 3 mainly includes a middle shell 15, an end shell 13, a plurality of dual-channel staged fuel nozzles 12, an orifice plate 14, a rich-burn premixed igniter 11, and a flame detector 1. The inner cavity of the flame tube 4 is the combustion area in the combustor. Wall cooling holes 35, main combustion holes 25, and mixing holes 24 are arranged on the flame tube 4 (as Figure 9 shown in the figure). A combustor inlet flow passage is formed between the flame tube 4 and the head shell 3 and the sleeve 5. By using the structures of the combustor head 3, the flame tube 4, and the sleeve 5, the primary air and secondary air of the combustor are distributed. The air distribution directly affects the internal flow field of the combustor. As Figure 8 shown in the figure, the primary air enters the combustor head 3 and forms the air in the main combustion zone, and the air-fuel ratio in the main combustion zone is limited not to exceed 1.8. The combustor head 3 is used to control the air-fuel ratio and fuel distribution of the dual-channel staged fuel nozzles 12. The secondary air enters the interior of the combustor through the wall cooling holes 35, main combustion holes 25, and mixing holes 24 opened on the flame tube 4. The air flow entering from the wall cooling holes 35 will form a stable gas film on the wall of the flame tube 4 to protect the flame tube 4 from ablation. The air flow entering from the main combustion holes 25 participates in the further combustion of the gas in the main combustion zone 18 and cools the gas. The air flow entering from the mixing holes 24 mixes and cools the gas entering the primary mixing zone 17.

[0037] To isolate the combustor head 3 from the flame tube 4, an orifice plate 14 is provided at the connection between the combustor head 3 and the flame tube 4. As Figure 6 shown in the figure, cooling holes 30 are densely opened on the orifice plate 14 to reduce the temperature of the combustor head 3, block the high-temperature backflow in the main combustion zone 18, and structurally separate the cavities of the combustor head 3 and the flame tube 4. Cooling holes 30 are arranged in a ring around the periphery of each dual-channel staged fuel nozzle 12 on the orifice plate 14, and an air flow layer can be formed outside the combustion flame surface in the main combustion zone 18. This air flow layer flows with the air flow in the main combustion zone 18.

[0038] To achieve the stable ignition function of the combustion chamber, a rich-burn premixed igniter 11 is provided at the head 3 of the combustion chamber for the start-up of the combustion chamber. For the specific structure of the rich-burn premixed igniter 11 of the present utility model, refer to the ignition device in the Chinese utility model patent "A New Type of Premixed Combustion Ignition System" with the authorization announcement number CN213089861U; as Figure 4 shown, the rich-burn premixed igniter 11 (referred to as the igniter for short) consists of an ignition channel 38 and a spark plug 37. Before ignition, first, the fuel in the rich-burn premixed igniter 11 and the compressed air at the outlet of the compressor are premixed with an air-fuel ratio of 0.8 to 1.2, and then the premixed fuel with low speed, low pressure, and sufficient mixing is sent into the ignition channel 38 and ignited by the spark plug 37. Since the airflow for spark plug 37 ignition is fully mixed and has high flow field stability, the ignition success rate can be improved. The premixed airflow in the rich-burn premixed igniter 11 is in a micro-swirl state, which can form an air film at the wall of the igniter to protect the wall of the igniter from being burned out.

[0039] To be able to monitor the combustion situation of the combustion chamber in real time, a flame detector 1 is provided at the central position of the head 3 of the combustion chamber. Since the combustion chamber head structure of the present utility model adopts a combined application of multiple fuel nozzles, a stable recirculation main combustion zone 18 is formed at the outlet of each double-channel staged fuel nozzle 12, and there will be no recirculation and heat return at the outlet position of the flame detector 1, avoiding damage to the flame detector 1 caused by high temperature. At the same time, a plurality of cooling holes 30 are arranged in a circular ring around the flame detector 1 on the orifice plate 14 for protection, so that the flow field temperature at the outlet of the flame detector 1 is low and stable.

[0040] To ensure the combustion stability of the main combustion zone 18 in the combustion chamber, the head 3 of the combustion chamber adopts a combined jet of multiple double-channel staged fuel nozzles 12 (referred to as fuel nozzles for short). The multiple fuel nozzles are evenly distributed circumferentially, the nozzle outlet is in-phase strong swirl, there is a spacing between each fuel nozzle, and a jet air film is formed through the cooling holes 30 to reduce the interference of the flow field between the fuel nozzles. The axis of the fuel nozzle forms a certain angle (preferably 7°) with the central axis of the combustion chamber, which can concentrate the flame in the main combustion zone 18 and utilize the heat transfer and heating effect of the flow field heat in the main combustion zone 18 to stabilize the flame in the main combustion zone.

[0041] To stabilize the flame in the main combustion zone, the present utility model designs the flow field and air-fuel ratio of the main combustion zone 18 of the combustion chamber, and controls the air-fuel ratio and flow field of the main combustion zone 18 by using the combustion chamber head structure and the primary air in the combustion chamber. Among them, the double-channel staged fuel nozzle 12 in the combustion chamber head structure is the main functional component for controlling the air-fuel ratio and air mixing effect of the main combustion zone.

[0042] For the specific structure of the dual-channel staged fuel nozzle 12 of the present utility model, refer to the Chinese utility model patent "A fuel nozzle for realizing premixed combustion and diffusion combustion" with the authorization announcement number CN215892445U; as Figure 3 shown, it includes a fuel supply pipe 21, a housing, a swirler and a central body; a diffusion fuel channel and a premixed fuel channel are provided inside the fuel supply pipe 21. The diffusion fuel enters the gas chamber 26 of the central body to control the stable combustion of the main combustion zone 18 at the outlet of the fuel nozzle, especially to ensure the flame stability during the power increase and power decrease processes of the combustion chamber. When the gas turbine operates under rated conditions, the fuel amount entering the gas chamber 26 is very low (about 5% - 10% of the total fuel amount), and the excess air coefficient corresponding to the diffusion fuel is always in a rich combustion state. The premixed fuel is mixed into the premixed channel 32 in a swirling state through the fuel injection holes 33 opened on the swirling vanes 34 to improve the mixing uniformity; the dual-channel staged fuel nozzle 12 integrates the mixer and the swirler, with a compact structure. The premixed channel 32 near the outlet of the fuel nozzle has a cross-section contraction design to ensure a relatively high outlet flow rate and avoid flashback. Compared with the conventional venturi tube, this structure is simpler and more compact.

[0043] During the full operating condition process of the combustion chamber, the premixed circuit is in a dry lean combustion state, which can effectively avoid the generation of ultra-high temperature and ensure that the fuel combustion efficiency is above 0.99. In the combustion chamber of the present utility model, chamfer structures are provided at positions with relatively large corners, and chamfers are also provided in the fuel channels inside the fuel nozzle to ensure that no eddy currents affecting the normal flow field are generated.

[0044] To more intuitively illustrate the present invention, the implementation mode of the present utility model will be further described in combination with embodiments. The following embodiments are only the preferred specific implementation modes of the present utility model, but the protection scope of the present utility model is not limited thereto. Any technical solution that can be obviously obtained by those skilled in the art within the technical scope disclosed by the present utility model, including simple changes or equivalent replacements, is within the protection scope of the present utility model.

[0045]

Embodiment

[0046] As Figures 1-6 shown, in this embodiment, the combustion chamber head 3 is installed in the combustion chamber. The combustion chamber mainly includes a fuel manifold group, a flame tube 4, a sleeve 5, the combustion chamber head 3 and related connectors.

[0047] The diffusion fuel manifold 6, the premixed fuel manifold 1 7, and the premixed fuel manifold 2 8 are all arranged in a circular ring around the periphery of the combustion chamber head 3. At the positions of the combustion chamber head 3 corresponding to each fuel nozzle, fuel is supplied into the gas cavity 26 and the premixed passage 32 in the fuel nozzle through the pilot fuel pipeline 9 or the premixed fuel pipeline 10 respectively. Among them, the two pipelines of the premixed fuel manifold 1 7 and the premixed fuel manifold 2 8 supply fuel to 2 groups of fuel nozzles respectively. The diffusion fuel manifold 6, the premixed fuel manifold 1 7, and the premixed fuel manifold 2 8 are fixed by the support frame 2.

[0048] The combustion chamber head 3 is fixedly connected to the flame tube 4 and the sleeve 5 through connecting bolts. The combustion chamber head 3 is provided with a rich-burn premixed igniter 11, a flame detector 1, a dual-channel staged fuel nozzle 12, and an orifice plate 14. Between the middle shell 15 and the end shell 13, and between the middle shell 15 and the sleeve 5, they are hermetically connected by bolts respectively to form an outer flow passage of the combustion chamber. The orifice plate 14 is connected to the flame tube 4 to form an inner cavity of the combustion chamber.

[0049] As Figure 8 shown, the structure of the combustion chamber divides the fluid domain of air into three parts. The first region 20 is the flow passage region formed between the flame tube 4, the sleeve 5, and the outer shell of the combustion chamber head 3. The compressed air coming out of the compressor enters from the tail of the combustion chamber and is divided into primary air, mixing air, and wall cooling gas film in the first region 20. The second region 21 is that after the primary air enters the combustion chamber head 3, it is divided into premixed passage air, diffusion passage air, and orifice plate jet air, which respectively enter the combustion chamber to participate in the main combustion zone air flow. The third region 22 is the inner region of the flame tube 4. This region is divided into a main combustion zone 18, a primary mixing zone 17, and a secondary mixing zone 16 by the main combustion holes 25 and mixing holes 24 on the flame tube 4. And the gas temperature decreases with the air mixing, and finally a stable, uniform air flow with a temperature of about 1300k is formed at the outlet of the flame tube 4. The structure of the combustion chamber head redistributes the primary air of the combustion chamber, dividing the primary air into orifice plate cooling air, air corresponding to the premixed fuel, and air corresponding to the diffusion fuel. The air flow of the combustion chamber head 3 directly reaches the main combustion zone 18, which is the most core part of the combustion chamber.

[0050] As Figure 1 、 Figure 2As shown in the figure, in this embodiment, the combustion chamber head structure mainly includes: a rich-burn pre-mixed igniter 11, a flame detector 1, a middle housing 15, an end housing 13, a dual-channel staged fuel nozzle 12, and an orifice plate 14. Four dual-channel staged fuel nozzles 12 are evenly distributed along the circumference of the combustion chamber head 3, and each dual-channel staged fuel nozzle 12 is radially deflected by 7° towards the center of the combustion chamber. The pilot fuel in the four dual-channel staged fuel nozzles 12 is supplied by a pilot fuel pipeline 9 and is uniformly controlled by a single valve, that is, the pilot fuel values in each fuel nozzle are equal. The pre-mixed fuel in the four dual-channel staged fuel nozzles 12 is supplied by two pre-mixed fuel pipelines 10 respectively, and each pre-mixed fuel pipeline 10 supplies two cross-opposed dual-channel staged fuel nozzles 12.

[0051] As Figure 1 , Figure 2 and Figure 6 shown, four dual-channel staged fuel nozzles 12 are evenly arranged along the circumference of the combustion chamber head 3. Each fuel nozzle has an outer pre-mixed combustion channel and a central diffusion combustion channel. During the operation of the combustion chamber, the pre-mixed combustion channel is the main one, and the main function of the diffusion combustion channel is to stabilize the flame during the power increase and decrease process of the combustion chamber. A swirler is arranged in the pre-mixed combustion channel, and the swirl angle is 45°. In this embodiment, the swirler is composed of 9 swirler vanes 34, and fuel injection holes 33 are opened on the swirler vanes 34, realizing the integration of the swirler and the mixer. The pre-mixed channel 32 in the dual-channel staged fuel nozzle 12 is designed as a cross-section contraction structure, and the cross-section contraction ratio is 0.7. When the high-pressure fluid passes through the pre-mixed channel 32, it plays a role in accelerating the speed.

[0052] The combustion chamber head 3 is provided with an orifice plate 14. As Figure 6 shown, the dual-channel staged fuel nozzles 12 are evenly arranged along the circumference of the orifice plate 14, and a flame detector 1 is arranged at the central position, and a rich-burn pre-mixed igniter 11 is arranged between two dual-channel staged fuel nozzles 12. First, the orifice plate 14 is used to isolate the combustion chamber head 3 from the flame tube 5, forming two temperature zones, which has a protective effect on the combustion chamber head 3; second, a plurality of cooling holes 30 are densely opened on the orifice plate 14, which are used to inject high-pressure air into the interior of the flame tube 4. The high-pressure air pushes the high-temperature gas flow in the main combustion zone inside the flame tube 4 backward, protecting the orifice plate 14 from being ablated; third, cooling holes 30 are distributed around the nozzle mounting holes 29, the igniter mounting holes 28, and the flame detector mounting holes 31 on the orifice plate 14, playing a protective role; finally, the air injected by the orifice plate 14 forms an air flow layer outside the flame surface in the main combustion zone 18, which can reduce the influence of combustion disturbance.

[0053] As Figure 1As shown, the rich-burn premixed igniter 11 is used to start the operation of the combustion chamber. Its axis has a 5° angle with the central axis of the combustion chamber, and it can form a dagger-shaped ignition flame at the central position of the main combustion zone 18. The rich-burn premixed igniter 11 is equipped with an ignition channel 38 and cooperates with the spark plug 37 to perform the ignition operation of the combustion chamber.

[0054] As Figure 4 shown, the gas-air mixture intake interface of the rich-burn premixed igniter 11 is arranged tangentially along the ignition channel 38, giving it a micro-swirl function and enabling a stable gas film protection layer to form on the igniter wall surface. The ignition success rate of this rich-burn premixed igniter 11 is better than that of a conventional igniter that only uses the direct ignition method of a spark plug.

[0055] As Figure 1 shown, the flame detector 1 is arranged at the central position of the head 3 of the combustion chamber, used to detect whether the rich-burn premixed igniter 11 ignites successfully, and monitor the combustion flame during the subsequent operation of the combustion chamber. If problems such as flameout occur, it can be adjusted conveniently and in a timely manner.

[0056] As Figure 1 shown, the end housing 13 and the middle housing 15 mainly play a role in guiding the flow. Together, they form the outer shell of the head 3 of the combustion chamber. Their design mainly considers the distribution amount of high-pressure air in the head 3 of the combustion chamber, enabling the high-pressure air to enter the air inlets of each fuel nozzle and the air inlets on the orifice plate under the guidance of the changing outer shell cavity, reducing the turbulence degree of the compressed air in the head 3 of the combustion chamber.

[0057] As Figure 3 shown, in this embodiment, the cross-sectional smoothness of each flow channel in the dual-channel staged fuel nozzle 12 is high, and fillet designs are carried out at the corner positions.

[0058] As Figure 9 shown, in this embodiment, the flame tube 4 is composed of 8 stacked and welded conical flame tube sheets 23. Among them, the number of flame tube sheets 23 corresponding to the main combustion zone 18 is 3, the number of flame tube sheets 23 corresponding to the primary mixing zone 17 is 3, and the number of flame tube sheets 23 corresponding to the secondary mixing zone 16 is 2. Wall cooling holes 35 are evenly arranged on each flame tube sheet 23, and a gas film guiding structure is formed at the gaps between the flame tube sheets 23. Each flame tube sheet 23 is provided with a thermal expansion groove 36; a row of main combustion holes 25 and a row of mixing holes 24 are arranged on the wall surface of the flame tube 4, dividing the internal area of the flame tube 4 into three parts: the main combustion zone 18, the primary mixing zone 17, and the secondary mixing zone 16. The number of wall cooling holes 35 corresponding to the main combustion zone 18 > the number of wall cooling holes 35 corresponding to the primary mixing zone 17 > the number of wall cooling holes 35 corresponding to the secondary mixing zone 16. The main combustion holes 25 and the mixing holes 24 are arranged staggeredly in the circumferential direction, and the positions of the main combustion holes 25 need to avoid the outlet positions of the dual-channel staged fuel nozzle 12.

[0059] The above are only the preferred specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution and its concept of the present utility model, making equivalent replacements or changes should be covered within the protection scope of the present utility model.

Claims

1. A gas turbine combustion chamber head structure, comprising a combustion chamber head consisting of a middle shell, an end shell, a perforated plate, a plurality of fuel nozzles, an igniter and a flame detector; characterized in that: The fuel nozzle is a dual-channel graded fuel nozzle, and the igniter is a rich-fuel premixed igniter; an open end of the middle shell is detachably connected to the end shell, and a orifice plate is provided at the other open end of the middle shell; the dual-channel graded fuel nozzle consists of a fuel channel and a nozzle body, and the fuel channel is installed in a fuel channel mounting hole uniformly opened along the circumference of the middle shell, and the nozzle body is arranged at an angle along the radial direction of the middle shell, and the axis of the nozzle body and the axis of the middle shell form an angle of 3° to 10°, and the injection end faces the center of the middle shell; the orifice plate is provided with a nozzle mounting hole at the point where the dual-fuel nozzle body passes through; the orifice plate is also provided with an igniter mounting hole, a flame detector mounting hole and a plurality of cooling holes; the rich-fuel premixed igniter is arranged between two dual-channel graded fuel nozzles, and is arranged at an angle along the radial direction of the middle shell, and its ignition end faces the center of the middle shell, and the two ends of the rich-fuel premixed igniter are respectively fixed in the end shell and the igniter mounting hole; The flame detector is arranged along the axis of the middle shell, and the two ends of the flame detector are respectively fixed in the end shell and the flame detector mounting hole; the cooling holes are densely distributed around the nozzle mounting holes, the igniter mounting holes and the flame detector mounting holes.

2. A gas turbine combustion chamber head structure according to claim 1, characterized in that: The dual-channel graded fuel nozzle consists of a fuel supply pipe, an outer shell, a vortex finder and a center body, and is provided with a premixing channel inside. The cross-sectional area of ​​the premixing channel gradually decreases from the inside to the outside, and the cross-sectional contraction ratio is 0.6 to 0.8; a gas cavity and an air cavity are provided inside the center body.

3. A gas turbine combustion chamber head structure according to claim 1, characterized in that: There are four dual-channel staged fuel nozzles.

4. A gas turbine combustion chamber head structure according to claim 1, characterized in that: The rich fuel premix igniter consists of a spark plug and an ignition channel. The spark plug is arranged at one end of the ignition channel. The ignition channel is provided with a gas-air mixture intake interface at the end close to the spark plug. The gas-air mixture intake interface is arranged tangentially along the ignition channel.

5. A gas turbine combustion chamber head structure according to claim 1, characterized in that: The radial angle between the axis of the rich fuel premixed igniter and the axis of the middle shell is 5° to 7°.

6. A gas turbine combustion chamber, characterized in that: It comprises a gas turbine combustion chamber head structure as described in any one of claims 1 to 5; it also comprises a fuel manifold group, a flame tube and a sleeve; the fuel output end of the fuel manifold group is connected to the fuel input end of each dual-channel graded fuel nozzle; one end of the flame tube is connected to one end of the middle shell body provided with a orifice plate, the sleeve and the flame tube are coaxially arranged with the orifice plate, and an annular channel is left between the flame tube and the sleeve.

7. A gas turbine combustion chamber according to claim 6, characterized in that: The fuel manifold group consists of a premixed fuel manifold one, a premixed fuel manifold two and a diffusion fuel manifold; the premixed fuel manifold one, the premixed fuel manifold two and the diffusion fuel manifold are all annular manifolds, which are arranged at intervals at the outer end of the combustion chamber head away from the flame tube through a support frame; the premixed channel in the dual-channel graded fuel nozzle is connected to the premixed fuel manifold one or the premixed fuel manifold two through a premixed fuel pipeline, and the fuel gas chamber in the dual-channel graded fuel nozzle is connected to the diffusion fuel manifold through a duty fuel pipeline.

8. A gas turbine combustion chamber according to claim 6, characterized in that: There are four dual-channel staged fuel nozzles, of which two cross-opposing ones form a group, the premixing channels in the first group of dual-channel staged fuel nozzles are connected to the premixing fuel manifold 1 through a premixing fuel pipeline, and the premixing channels in the second group of dual-channel staged fuel nozzles are connected to the premixing fuel manifold 2 through a premixing fuel pipeline.

9. A gas turbine combustion chamber according to claim 6, characterized in that: The flame tube has a stacked annular structure, that is, it is composed of a plurality of stacked conical flame tube segments, with a gap between two adjacent flame tube segments, and a plurality of wall cooling holes and a plurality of thermal expansion grooves are arranged circumferentially on each flame tube segment; a row of main combustion holes and a row of mixing holes are also arranged at intervals on the flame tube, dividing the interior of the flame tube into a main combustion zone, a primary mixing zone and a secondary mixing zone along the flame injection direction.

10. A gas turbine combustion chamber according to claim 9, characterized in that: The number of wall cooling holes on the flame tube segment corresponding to the main combustion zone is greater than the number of wall cooling holes on the flame tube segment corresponding to the primary mixing zone and greater than the number of wall cooling holes on the flame tube segment corresponding to the secondary mixing zone.

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