Pneumatic simplified test structure considering micro-mixing combustion and staged combustion

Abstract

The invention discloses a pneumatic simplified test structure considering micro-mixing combustion and staged combustion, and the structure comprises a combustion-spraying combined body unit, and a plurality of combustion-spraying combined bodies are arrayed in the circumferential direction, and are used for generating an annular combustion chamber structure. The combustion and spraying combined body unit comprises a bottom plate, a plurality of integrated partition plates and a micro-mixing combustion chamber head. The multiple integrated partition plates are fixedly connected to the bottom plate, and the distance between every two adjacent integrated partition plates is the same. A cover plate is arranged on the sides, away from the bottom plate, of the integrated partition plates, and a plurality of mainstream fuel gas circulation channels are formed among the bottom plate, the cover plate and the integrated partition plates. Secondary flow gas inlet grooves are formed in the two opposite side walls of one main flow fuel gas circulation channel; and a plurality of groups of air inlet holes are formed in the micro-mixing combustion chamber head and are in one-to-one correspondence with the plurality of mainstream fuel gas circulation channels. The method is simplified on the basis of pure pneumatic modeling, the complex flow field characteristic of micro-mixing combustion is kept, meanwhile, the test difficulty is reduced to a great extent, and the test cost is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ground heavy gas turbines, and particularly relates to a pneumatic simplified test structure considering micro-mixed combustion and staged combustion. Background Art

[0002] As the crown of today's industry, gas turbines represent a country's top industrial design and manufacturing capabilities. The working principle of gas turbines is similar to that of aero-engines. However, since gas turbines have always been fixed on the ground, they do not pay attention to maneuvering parameters such as thrust and thrust-to-weight ratio. In order to achieve industrial-scale power generation, ground gas turbines often pursue excellent working efficiency to reduce power generation costs and thus increase production and operation benefits. Gas turbines adopt the Brayton cycle. From the principle of this cycle, in order to improve the working efficiency, the ground gas turbine must continuously increase the temperature before the turbine. At the same time, when the temperature before the turbine increases, its optimal pressure ratio should also increase accordingly; in order to reduce the emissions of pollutants during combustion, lean combustion technology is adopted to mainly reduce the emissions of nitrogen oxides during the combustion process.

[0003] However, more powerful working performance and a cleaner combustion condition will also pose a series of challenges to the design of gas turbines. More powerful working performance brings a higher temperature before the turbine. When the higher temperature before the turbine exceeds the temperature resistance limit of the material, the turbine has to adopt a cooling design method to reduce the temperature of the blades; for combustion, in order to achieve a cleaner combustion, although the lean-premixed combustion method can reduce pollutant emissions, it will cause a series of new problems. Regarding the cooling structure design of the first-stage guide vane, due to the uneven distribution of the temperature at the outlet of the combustion chamber, a hot spot will be formed at the inlet. The local high-temperature area of the hot spot makes the guide vane bear a higher temperature load, which will increase the risk of local high-temperature burning of the blade. At the same time, cold and hot gas separation occurs in the moving blade, which brings great difficulties and uncertainties to the cooling design of aero-engines; at the same time, as the axial length of the engine combustion chamber gradually shortens, the swirl generated by the combustion chamber swirler has not completely dissipated at the outlet, and the residual swirl will enter the turbine component along with the mainstream. The swirl will form an obvious secondary flow at the mid-span of the blade. During the propagation downstream, the strong swirl will entrain the nearby film cooling gas. The secondary flow vortex carries the cooling gas downward, resulting in insufficient cold gas coverage on the blade surface and greatly reducing the cooling efficiency. Current research shows that the combined action of swirl and hot spot will greatly affect the cooling efficiency of turbine blades. The hot spot itself has a higher temperature. The swirl weakens the thermal protection of the turbine blade by entraining the cooling film. At the same time, the interaction between the two is manifested in that the hot spot is continuously carried downstream under the entrainment of the swirl. The high turbulence of the swirl enhances the heat transfer between the high-temperature fluid and the wall plate. The interaction between the two further deteriorates the thermal environment of the turbine blade.

[0004] Therefore, how to resolve the conflict between high performance, high operating conditions and difficult design of heavy-duty gas turbines is an urgent problem to be solved in the current field. Summary of the Invention

[0005] The object of the present invention is to provide a pneumatic simplified test structure considering micro-mixed combustion and staged combustion to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides a pneumatic simplified test structure considering micro-mixed combustion and staged combustion, including a combustion and injection combined unit, and a plurality of the combustion and injection combined units are arranged in a circumferential array to generate an annular combustion chamber structure;

[0007] The combustion and injection combined unit includes:

[0008] A bottom plate, the top end of the bottom plate is connected to the combustion chamber air inlet surface;

[0009] A plurality of integrated partition plates, the plurality of integrated partition plates are all fixedly connected to the bottom plate, and the distance between adjacent two integrated partition plates is the same; a cover plate is arranged on the side of the integrated partition plate away from the bottom plate, and a plurality of mainstream gas flow channels are formed between the bottom plate, the cover plate and the plurality of integrated partition plates; secondary flow air inlet grooves are opened on the opposite side walls of one of the mainstream gas flow channels.

[0010] A micro-mixed combustion chamber head for mixing experimental gases; the micro-mixed combustion chamber head is arranged on the side of the combustion chamber air inlet surface close to the integrated partition plate, and the micro-mixed combustion chamber head is provided with multiple groups of air inlet holes, and the multiple groups of air inlet holes are respectively arranged in one-to-one correspondence with the plurality of mainstream gas flow channels.

[0011] Preferably, the air outlet direction of the secondary flow air inlet groove is perpendicular to the mainstream gas flow channel.

[0012] Preferably, the secondary flow air inlet groove is arranged in the middle of the integrated partition plate.

[0013] Preferably, the length of the secondary flow air inlet groove is 50 mm to 75 mm, and the width is 30 mm to 40 mm.

[0014] Preferably, the number of the integrated partition plates is four, three mainstream gas flow channels are formed between the four integrated partition plates, and the secondary flow air inlet groove is arranged in the middle mainstream gas flow channel.

[0015] Preferably, the mainstream gas flow channel includes a straight section and a contraction section, and the straight section is arranged close to the micro-mixed combustion chamber head.

[0016] Preferably, each set of the air inlet holes includes a plurality of round holes arranged in a rectangular array.

[0017] Preferably, the row pitch of the round holes is 6 mm, the hole pitch is 5 mm, and the hole diameter is 3 mm.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] The pneumatic simplified test structure considering micro-mixed combustion and staged combustion provided by the present invention simulates the inlet flow field of micro-mixed combustion by opening equidistant air inlet holes on the head of the micro-mixed combustion chamber, and simulates secondary combustion by opening secondary flow air inlet grooves on the wall surface of the mainstream gas flow passage. It is simplified on the basis of pure pneumatic modeling, which not only maintains the complex flow field characteristics of micro-mixed combustion, but also greatly reduces the test difficulty, simplifies the test process, and significantly reduces the design and test costs. It can be applied to the pure pneumatic verification test of the ground heavy-duty gas turbine combustion spray combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 is a schematic structural diagram of the present invention;

[0022] Figure 2 is an arrangement diagram of the air inlet holes of the present invention;

[0023] Figure 3 is a schematic diagram of the secondary flow air inlet groove of the present invention;

[0024] In the figure: 1, bottom plate; 2, integrated partition; 3, head of micro-mixed combustion chamber; 4, combustion chamber air inlet surface; 5, secondary flow air inlet groove; 6, air inlet hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0026] Such as Figures 1 to 3As shown in the figure, the present invention provides a pneumatic simplified test structure considering micro-mixing combustion and staged combustion, including a combustion and injection combined unit, and a plurality of combustion and injection combined units are arranged in a circumferential array to generate an annular combustion chamber structure;

[0027] The combustion and injection combined unit includes:

[0028] A bottom plate 1, the top end of the bottom plate 1 is connected to the combustion chamber air inlet surface 4;

[0029] A plurality of integrated partitions 2, the plurality of integrated partitions 2 are all fixedly connected to the bottom plate 1, and the distance between adjacent two integrated partitions 2 is the same; a cover plate is arranged on the side of the integrated partition 2 away from the bottom plate 1, and a plurality of mainstream gas flow channels are formed between the bottom plate 1, the cover plate and the plurality of integrated partitions 2; secondary air inlet grooves 5 are opened on the opposite side walls of one of the mainstream gas flow channels;

[0030] A micro-mixing combustion chamber head 3, which is used for mixing experimental gases; the micro-mixing combustion chamber head 3 is arranged on the side of the combustion chamber air inlet surface 4 close to the integrated partition 2, and the micro-mixing combustion chamber head 3 is provided with a plurality of groups of air inlet holes 6, and the plurality of groups of air inlet holes 6 are respectively arranged in one-to-one correspondence with the plurality of mainstream gas flow channels.

[0031] In view of the characteristics of micro-mixing combustion and staged combustion, the present invention simplifies on the basis of pure pneumatic modeling, optimizes the pneumatic test scheme, adopts the simplified pneumatic design configuration, and uses the pneumatic simulation method to simulate the flow field characteristics of micro-mixing combustion and staged combustion without carrying out combustion reactions. It not only maintains the complex flow field characteristics of micro-mixing combustion, but also greatly reduces the test difficulty, simplifies the test process, and significantly reduces the design and test costs. It can be applied to the pure pneumatic verification test of the combustion and injection combined body of ground heavy-duty gas turbines.

[0032] In a further optimized scheme, the outlet direction of the secondary air inlet groove 5 is perpendicular to the mainstream gas flow channel.

[0033] In a further optimized scheme, the secondary air inlet groove 5 is arranged in the middle of the integrated partition 2.

[0034] In a further optimized scheme, the length of the secondary air inlet groove 5 is 50 mm to 75 mm, and the width is 30 mm to 40 mm.

[0035] In a further optimized scheme, the number of the integrated partitions 2 is four, three mainstream gas flow channels are formed between the four integrated partitions 2, and the secondary air inlet groove 5 is arranged in the middle mainstream gas flow channel.

[0036] In a further optimized scheme, the mainstream gas flow channel includes a straight section and a contraction section, and the straight section is arranged close to the micro-mixing combustion chamber head 3.

[0037] For a further optimized solution, a single set of air inlet holes 6 includes a plurality of circular holes arranged in a rectangular array.

[0038] For a further optimized solution, the row spacing of the circular holes is 6 mm, the hole spacing is 5 mm, and the hole diameter is 3 mm.

[0039] The pneumatic simplified test structure considering micro-mixing combustion and staged combustion provided by the present invention has the micro-mixing combustion chamber head 3 located at the uppermost upstream of the entire structure, which is used to simulate the lean combustion condition. Due to the short distance of the micro-mixing combustion chamber head 3 and the relatively dense arrangement of the micro-mixing air inlet holes 6, the non-uniformity of the temperature field disappears within an extremely short length due to the mixing effect between the micro-mixing pipes. When the mainstream incoming flow passes through the head of the fuel injection and combustion combination, it is restricted by the structure of the air inlet holes 6, which has a rectifying effect on the outgoing airflow. At the same time, after the air flow in the air inlet holes 6 flows out, a typical jet structure is formed, thereby constructing a micro-mixing multi-jet inlet. After the air flow enters the mainstream gas flow channel, at the beginning, the mainstream flow channel is straight and the air flow will not accelerate. When the air flow passes through the middle section of the mainstream flow channel, the flow channel is in a contracted shape, which is beneficial to simulating the effect of wrapping the flame. After passing through the rear section of the integrated partition plate 2, a flow change similar to that inside the turbine guide vane occurs. The two secondary flow inlet slots 5 are respectively located on both sides of the mainstream flow channel and are arranged oppositely. The secondary flow inlet slots 5 simulate secondary combustion, and use the secondary flow with strong incident momentum to enhance the mixing effect with the mainstream, which is beneficial to the mixing interaction with the mainstream and improves the uniformity of the downstream flow. This way of slot air inlet can achieve the purpose of enhancing the momentum of the secondary flow jet and the purpose of simulating the hot jet with the cold jet, reducing the test difficulty and the requirements for the test bench, thereby reducing the overall complexity of the test and being beneficial to the overall aerodynamic optimization research and development.

[0040] The present invention simplifies on the basis of pure aerodynamic shaping, which not only maintains the complex flow field characteristics of micro-mixing combustion, but also greatly reduces the test difficulty, simplifies the test process, and significantly reduces the design and test costs. It can be applied to the pure aerodynamic verification test of the fuel injection and combustion combination of ground heavy gas turbines.

[0041] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A pneumatic simplified test structure considering micro-mixing combustion and staged combustion, characterized in that It includes a combustion and injection combined unit, and a plurality of the combustion and injection combined units are arranged in a circumferential array to generate an annular combustion chamber structure; The combustion and injection combined unit includes: A bottom plate (1), the top end of the bottom plate (1) is connected to the combustion chamber air inlet surface (4); A plurality of integrated partition plates (2), the plurality of integrated partition plates (2) are all fixedly connected to the bottom plate (1), and the distance between adjacent two integrated partition plates (2) is the same; a cover plate is arranged on the side of the integrated partition plate (2) away from the bottom plate (1), and a plurality of main stream gas flow channels are formed between the bottom plate (1), the cover plate and the plurality of integrated partition plates (2); secondary flow air inlet grooves (5) are opened on the opposite side walls of one of the main stream gas flow channels; A micro-mixing combustion chamber head (3) for mixing experimental gases; the micro-mixing combustion chamber head (3) is arranged on the side of the combustion chamber air inlet surface (4) close to the integrated partition plate (2), and the micro-mixing combustion chamber head (3) is provided with multiple groups of air inlet holes (6), and the multiple groups of air inlet holes (6) are respectively arranged in one-to-one correspondence with the multiple main stream gas flow channels.

2. The pneumatic simplified test structure considering micro-hybrid combustion and staged combustion according to claim 1, characterized in that, The air outlet direction of the secondary flow air inlet groove (5) is perpendicular to the main stream gas flow channel.

3. The pneumatic simplified test structure considering micro-mixing combustion and staged combustion according to claim 1, characterized in that, The secondary flow air inlet groove (5) is arranged in the middle of the integrated partition plate (2).

4. The pneumatic simplified test structure considering micro-mixed combustion and staged combustion according to claim 1, characterized in that, The length of the secondary flow air inlet groove (5) is 50 mm to 75 mm, and the width is 30 mm to 40 mm.

5. The pneumatic simplified test structure considering micro-hybrid combustion and staged combustion according to claim 1, characterized in that, The number of the integrated partition plates (2) is four, and three main stream gas flow channels are formed between the four integrated partition plates (2), and the secondary flow air inlet groove (5) is arranged in the middle main stream gas flow channel.

6. The pneumatic simplified test structure considering micro-mixed combustion and staged combustion according to claim 1, characterized in that The main stream gas flow channel includes a straight section and a contraction section, and the straight section is arranged close to the micro-mixing combustion chamber head (3).

7. The pneumatic simplified test structure considering micro-mixed combustion and staged combustion according to claim 1, characterized in that, A single group of the air inlet holes (6) includes a plurality of circular holes arranged in a rectangular array.

8. The pneumatic simplified test structure considering micro-hybrid combustion and staged combustion according to claim 7, characterized in that The pitch of the circular hole rows is 6 mm, the hole spacing is 5 mm, and the hole diameter is 3 mm.

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