A head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization

Abstract

The present invention relates to a head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization, belonging to the technical field of gas turbine combustors for marine liquid fuels. It solves the problems of unsatisfactory atomization effect and high pollutant generation amount in the prior art. It includes a main combustion pre-film atomizing swirler, a fairing and a duty-class swirler. The main combustion pre-film atomizing swirler and the duty-class swirler are arranged in the fairing. The main combustion pre-film atomizing swirler includes a main combustion stage oil passage, a secondary axial swirler, a primary axial swirler and a sub-channel. The primary axial swirler is arranged inside the secondary axial swirler. The side wall of the primary axial swirler is machined with a pre-film atomizing nozzle cavity and a pre-film nozzle pressure cavity. The pre-film atomizing nozzle cavity and the pre-film nozzle pressure cavity are communicated through a swirl hole. The main combustion stage oil passage is communicated with the pre-film nozzle pressure cavity. The fuel atomization level is improved, and while meeting the performance parameters of the whole machine, the atomization degree of the fuel is increased under small working conditions to reduce the pollutant emission level.

Description

Technical Field

[0001] The present invention relates to a low-pollution combustion chamber head structure, belonging to the technical field of gas turbine combustion chambers for ship liquid fuels. Background Art

[0002] At present, pressure atomizing nozzles are mostly used for fuel injection in combustion chambers. The fuel is atomized by the huge pressure difference inside the nozzle. However, when the operating condition is small, the oil pressure is low, resulting in unsatisfactory atomization effect. Local fuel enrichment appears downstream of the injection point, causing local high temperature in combustion and a relatively high amount of pollutants generated.

[0003] Therefore, there is an urgent need to propose a multi-point staged low-pollution combustion chamber head structure based on main combustion pre-film atomization to solve the above technical problems. Summary of the Invention

[0004] The present invention solves the problems in the prior art that when the operating condition is small, the oil pressure is low, resulting in unsatisfactory atomization effect, local fuel enrichment appears downstream of the injection point, causing local high temperature in combustion and a relatively high amount of pollutants generated. The present invention provides a multi-point staged low-pollution combustion chamber head structure based on main combustion pre-film atomization. A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0005] Technical Solution of the Present Invention:

[0006] A multi-point staged low-pollution combustion chamber head structure based on main combustion pre-film atomization includes a main combustion pre-film atomizing swirler, a fairing, and a pilot swirler. A plurality of circumferentially arranged main combustion pre-film atomizing swirlers and a centrally arranged pilot swirler are arranged inside the fairing. The main combustion pre-film atomizing swirler includes a main combustion stage oil passage, a secondary axial swirler, a primary axial swirler, and a sub-channel. The primary axial swirler is arranged inside the secondary axial swirler. A pre-film atomizing nozzle cavity and a pre-film nozzle pressure cavity are machined on the side wall of the primary axial swirler. The pre-film atomizing nozzle cavity and the pre-film nozzle pressure cavity are connected through a swirling hole. One end of the main combustion stage oil passage is connected to the pre-film nozzle pressure cavity through the sub-channel.

[0007] Preferably: The middle of the secondary axial swirler has a throat structure, the end of the primary axial swirler has a hemispherical structure, and a plurality of circumferentially equally spaced central jet holes are machined on the hemispherical structure of the primary axial swirler.

[0008] Preferably: The main combustion stage oil passage is arranged inside the primary axial swirler through three circumferentially equally spaced sub-channels.

[0009] Preferably: the swirling holes are arranged obliquely, the number of the swirling holes is nine, and the nine swirling holes are arranged equidistantly in the circumferential direction.

[0010] Preferably: the number of the main combustion pre-film atomizing swirlers is nine, and the nine main combustion pre-film atomizing swirlers are arranged equidistantly in the circumferential direction.

[0011] Preferably: it further includes a chassis. The secondary axial swirler of the main combustion pre-film atomizing swirler is connected to the fairing through the chassis. A first through hole is correspondingly arranged on the chassis at the connection position with the secondary axial swirler. The duty-class swirler is connected to the fairing through the chassis. A second through hole is correspondingly arranged on the chassis at the connection position with the duty-class swirler.

[0012] Preferably: it further includes an external fuel pipeline and a cover plate. External fuel pipelines are arranged at the corresponding positions of the main combustion stage oil passage and the duty-class swirler on the cover plate. The external fuel pipelines are communicated with the main combustion stage oil passage and the duty-class swirler.

[0013] The present invention has the following beneficial effects:

[0014] 1. In the present invention, the primary axial swirler and the secondary axial swirler act together to break the liquid film and oil film flowing out of the pre-film atomizing nozzle cavity, improving the fuel atomization level. And by injecting high-speed air flow through the central jet hole, the central recirculation zone can be eliminated, reducing the range of the recirculation zone and making it more stable, which is helpful for stable ignition. It can also push the atomized oil-gas mixture into the flame tube at high speed to avoid spontaneous combustion at the throat, improving the fuel atomization degree and reducing the pollutant emission level under small working conditions while meeting the overall machine performance parameters;

[0015] 2. The swirling holes of the present invention can make the fuel have a swirling velocity before forming a liquid film to improve the liquid film atomization level.

[0016] 3. The external fuel pipeline of the present invention can effectively prevent the fuel pipeline from coking caused by high temperature.

[0017] 4. The fairing designed in the present invention can make the air intake of each stage of the swirler at the head of the combustion chamber more uniform and the temperature more uniform, providing a solution idea for the uneven air intake at the head of the multi-point staged combustion chamber. Description of the Drawings

[0018] Figure 1 is a three-dimensional view of a multi-point staged low-pollution combustion chamber head structure based on main combustion pre-film atomization;

[0019] Figure 2 is a front view of a multi-point staged low-pollution combustion chamber head structure based on main combustion pre-film atomization;

[0020] Figure 3 is Figure 2 the A-A cross-sectional view in

[0021] Figure 4 is Figure 3 The enlarged view at position B in

[0022] Figure 5 is the structural schematic diagram of the main combustion pre-film atomizing swirler;

[0023] Figure 6 is Figure 5 the sectional view taken along C-C in

[0024] Figure 7 is the sectional view of the usage state of the head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization;

[0025] Figure 8 is Figure 7 the enlarged view at position D in

[0026] Figure 9 is the three-dimensional view of the usage state of the head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization.

[0027] In the figure: 1 - external fuel pipeline, 2 - main combustion pre-film atomizing swirler, 3 - fairing, 4 - duty swirler, 5 - chassis, 6 - cover plate, 2-1 - main combustion stage oil passage, 2-2 - secondary axial swirler, 2-3 - pre-film atomizing nozzle cavity, 2-4 - central jet hole, 2-5 - primary axial swirler, 2-6 - throat structure, 2-7 - sub-channel, 2-8 - pre-film nozzle pressure cavity. Specific embodiments

[0028] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be described below through specific embodiments shown in the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0029] Specific embodiment 1: In combination with Figures 1-9To describe this embodiment, a head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment includes a main combustion pre-film atomization swirler 2, a fairing 3, and a pilot swirler 4. A number of circumferentially arranged main combustion pre-film atomization swirlers 2 and a pilot swirler 4 coaxially arranged with the fairing 3 are provided inside the fairing 3. The funnel-shaped fairing can make the air intake of each stage of the swirler in the combustor head more uniform, and can provide a solution to the problem of uneven air intake in the multi-point staged combustor head. The small-diameter end of the fairing is fixedly connected to the annular combustor flame tube 7. A splash guard is provided at the end of the annular combustor flame tube 7, and there are cooling holes on the splash guard for further cooling. The splash guard is welded to the fairing 3. The main combustion pre-film atomization swirler 2 includes a main combustion stage oil passage 2-1, a secondary axial swirler 2-2, a primary axial swirler 2-5, and a sub-channel 2-7. The primary axial swirler 2-5 is arranged inside the secondary axial swirler 2-2. The outer wall of the primary axial swirler 2-5 is coaxially and fixedly arranged with the inner wall of the secondary axial swirler 2-2 through the secondary axial swirler blades of the secondary axial swirler 2-2. An annular pre-film atomization nozzle cavity 2-3 and a pre-film nozzle pressure cavity 2-8 are machined on the side wall of the primary axial swirler 2-5. There is a partition between the pre-film atomization nozzle cavity 2-3 and the pre-film nozzle pressure cavity 2-8, and swirl holes 2-9 are machined on the partition. The pre-film atomization nozzle cavity 2-3 and the pre-film nozzle pressure cavity 2-8 are communicated through the swirl holes 2-9. One end of the main combustion stage oil passage 2-1 is communicated with the pre-film nozzle pressure cavity 2-8 through the sub-channel 2-7. In the present invention, an oil film type nozzle and a first-stage and a second-stage swirler arranged above and below the nozzle are used for oil film breakup. Compared with the traditional main combustion swirler, the fuel atomization level is improved. And by adding a direct injection orifice (central jet orifice 2-4) to inject high-speed air flow, the central recirculation zone can be eliminated, the range of the recirculation zone is reduced and more stable, which is helpful for stable ignition. It can also push the atomized oil-gas mixture into the flame tube at high speed to avoid spontaneous combustion at the throat. A swirl hole with an angle of 45° to the axis is provided in the fuel passage of the main combustion swirler, which can make the fuel have a swirl velocity before forming a liquid film to improve the liquid film atomization level, and while meeting the overall engine performance parameters, improve the fuel atomization degree and reduce the pollutant emission level under small operating conditions.

[0030] Specific Embodiment 2: In combination with Figures 1-9To describe this embodiment, a head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment. The middle part of the secondary axial swirler 2-2 has a throat structure 2-6, and the end of the primary axial swirler 2-5 has a hemispherical structure. A number of circumferentially equally spaced central jet holes 2-4 are machined on the hemispherical structure of the primary axial swirler 2-5; the central jet holes 2-4 are straight jet holes. The high-speed air flow ejected from the central jet holes 2-4 can eliminate the central recirculation zone, reduce the range of the recirculation zone and make it more stable, which is helpful for stable ignition. It can also push the atomized oil-gas mixture into the combustion chamber at high speed to avoid spontaneous combustion at the throat; under the action of the fuel supply system pressure, the liquid fuel flows through the main combustion stage oil passage 2-1, the sub-channel 2-7, the pre-film nozzle pressure chamber 2-8, and the pre-film atomizing nozzle chamber 2-3 and flows out in the form of a liquid film. The primary axial swirler 2-5 has a number of circumferentially arranged blades, and the secondary axial swirler 2-2 has a number of circumferentially arranged blades. The blades of the primary axial swirler 2-5 and the blades of the secondary axial swirler 2-2 have opposite swirl directions, that is, the directions of the two swirl blades are opposite. Therefore, the liquid film is sheared and broken at the place where the central airflows meet, that is, at the position where the liquid film is ejected or flows out; that is, after the liquid film flows out, it is axially pulled by the annular primary axial swirler 2-5 to break axially and is also sheared by the annular secondary axial swirler 2-2. The oil film is broken under the combined action of the two to achieve atomization, as Figure 3 shown. The main combustion stage oil passage 2-1 is located on the left side of the central jet hole 2-4, the primary axial swirler 2-5 is located on the left side of the throat structure 2-6, the central jet hole 2-4 is located at the position corresponding to the pre-film nozzle pressure chamber 2-8, one end of the primary axial swirler 2-5 is located inside the secondary axial swirler 2-2, and the other end is located outside the secondary axial swirler 2-2.

[0031] Specific Embodiment Three: Combining Figures 1-9 To describe this embodiment, a head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment. The main combustion stage oil passage 2-1 is arranged inside the primary axial swirler 2-5 through three circumferentially equally spaced sub-channels 2-7.

[0032] Specific Embodiment Four: Combining Figures 1-9Description of this embodiment: A head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment. The swirl holes 2-9 are arranged obliquely. The inclination direction of the swirl holes 2-9 is the same as that of the blades of the secondary axial swirler 2-2, but the specific inclination angles can be the same or different. The number of the swirl holes 2-9 is nine, and the nine swirl holes 2-9 are circumferentially equidistantly arranged. The liquid fuel is divided into three paths after passing through the main combustion stage oil passage 2-1 and enters the pre-film nozzle pressure chamber 2-8, where the pressure is reduced and the speed is increased. Then, it passes through the square swirl holes 2-9 at an angle of 45° with the main axis direction to obtain a swirling velocity, improving the film-forming quality after being ejected from the pre-film atomization nozzle chamber 2-3. Compared with the conventional pressure atomization centrifugal nozzle, the present invention makes the fuel distribution more uniform in space, improves the fuel atomization level, greatly reduces the size of fuel droplets, improves the combustion efficiency, and reduces the pollutant emissions of the combustor.

[0033] Specific embodiment five: Combining Figures 1-9 Description of this embodiment: A head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment. The number of the main combustion pre-film atomization swirlers 2 is nine, and the nine main combustion pre-film atomization swirlers 2 are circumferentially equidistantly arranged. The main combustion pre-film atomization swirlers 2 are circumferentially evenly distributed around the value class as the center, and can be designed into two levels according to the requirements according to the regular triangle (3) and the inverted triangle (6) to correspond to different working conditions, and can be opened separately or simultaneously for easy control of the working conditions. The regular triangle (3) is the main combustion first stage, and the inverted triangle (6) is the main combustion second stage. Only the value class is started under the working condition of 0-0.12, the value class and the main combustion first stage are started under the working condition of 0.12-0.5, and the value class, the main combustion first stage and the second stage are started under the working condition of 0.8-1.0, ensuring that the average temperature in the main combustion stage of the combustor is relatively low, making the fuel atomization more sufficient, especially under small working conditions, improving the mixing level and combustion efficiency, thereby reducing the pollutant emission level.

[0034] Specific embodiment six: Combining Figures 1-9 Description of this embodiment: A head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment. It further includes a chassis 5. The outer wall of the secondary axial swirler 2-2 of the main combustion pre-film atomization swirler 2 is fixedly connected to the inner wall of the fairing 3 through the chassis 5. A first through hole is correspondingly arranged on the chassis 5 at the connection with the secondary axial swirler 2-2. The outer wall of the value class swirler 4 is fixedly connected to the inner wall of the fairing 3 through the chassis 5. A second through hole is correspondingly arranged on the chassis 5 at the connection with the value class swirler 4.

[0035] Specific embodiment seven: Combining Figures 1-9To describe this embodiment, a head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization in this embodiment further includes an external fuel pipeline 1 and a cover plate 6. The external fuel pipeline 1 is fixedly arranged at positions corresponding to the main combustion stage oil passage 2-1 and the pilot stage swirler 4 on the cover plate 6. The external fuel pipeline 1 includes a first pipeline arranged in the center and a second pipeline arranged circumferentially. The second pipeline and the first pipeline of the external fuel pipeline 1 are respectively communicated with the main combustion stage oil passage 2-1 and the pilot stage swirler 4, and the external fuel pipeline 1 is communicated with the fuel supply system. The complex structure of the external fuel pipeline 1 can be placed outside the casing, which can effectively prevent coking of the fuel pipeline caused by high temperature. The present invention is integrally installed at the head of the annular combustor flame tube and can be matched with different types of casings, and the cover plate of the external fuel pipeline can also be deformed in different ways.

[0036] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined. Those skilled in the art can exhaust all possibilities according to the mathematical knowledge of permutation and combination. Therefore, the present invention will no longer describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A head structure of a multi-point staged low-pollution combustor based on main combustion pre-film atomization, characterized in that: It includes a main combustion pre-film atomizing swirler (2), a fairing (3) and a duty-class swirler (4). Inside the fairing (3), several main combustion pre-film atomizing swirlers (2) arranged circumferentially and a duty-class swirler (4) arranged at the center are provided. The main combustion pre-film atomizing swirler (2) includes a main combustion stage oil passage (2-1), a secondary axial swirler (2-2), a primary axial swirler (2-5) and a sub-channel (2-7). The primary axial swirler (2-5) is arranged inside the secondary axial swirler (2-2). The side wall of the primary axial swirler (2-5) is machined with a pre-film atomizing nozzle cavity (2-3) and a pre-film nozzle pressure cavity (2-8). The pre-film atomizing nozzle cavity (2-3) and the pre-film nozzle pressure cavity (2-8) are connected through a swirl hole (2-9). One end of the main combustion stage oil passage (2-1) is connected to the pre-film nozzle pressure cavity (2-8) through the sub-channel (2-7); In the fuel passage of the main combustion swirler, swirl holes are arranged at an angle of 45° to the axis; The middle part of the secondary axial swirler (2-2) has a throat structure (2-6). The end of the primary axial swirler (2-5) has a hemispherical structure. Several circumferentially equally spaced central jet holes (2-4) are machined on the hemispherical structure of the primary axial swirler (2-5); The central jet holes (2-4) are straight jet holes. The high-speed air flow ejected from the central jet holes (2-4) can eliminate the central recirculation zone, reduce the range of the recirculation zone and make it more stable, which helps to stabilize ignition. It can also push the atomized oil-gas mixture into the combustion chamber at high speed to avoid spontaneous combustion at the throat; The blades of the primary axial swirler (2-5) and the secondary axial swirler (2-2) have opposite swirl directions. After the liquid film flows out, it is axially pulled by the primary axial swirler (2-5) of the annular pipe, causing the liquid film to break axially and is also sheared by the secondary axial swirler (2-2) of the annular pipe. Under the combined action of the two, the oil film is broken and atomized; The main combustion stage oil passage (2-1) is arranged inside the primary axial swirler (2-5) through three circumferentially equally spaced sub-channels (2-7); The swirl holes (2-9) are inclined. The number of the swirl holes (2-9) is nine, and the nine swirl holes (2-9) are circumferentially equally spaced; The liquid fuel is divided into three paths after passing through the main combustion stage oil passage (2-1) and enters the pre-film nozzle pressure cavity (2-8). It reduces pressure and increases speed in the pressure cavity, and then passes through the square swirl holes (2-9) at an angle of 45° to the main axis direction to obtain a swirl velocity, improving the film-forming quality after being ejected from the pre-film atomizing nozzle cavity (2-3).

2. The head structure of a multi-point staged low-pollution combustion chamber based on main combustion pre-film atomization according to claim 1, wherein: The number of the main combustion pre-film atomizing swirlers (2) is nine, and the nine main combustion pre-film atomizing swirlers (2) are circumferentially equally spaced.

3. A head structure of a multi-point staged low-pollution combustion chamber based on main combustion pre-film atomization according to claim 2, characterized in that: It further includes a chassis (5). The secondary axial swirler (2-2) of the main combustion pre-film atomizing swirler (2) is connected to the fairing (3) through the chassis (5). A first through hole is correspondingly arranged on the chassis (5) at the connection with the secondary axial swirler (2-2). The duty-class swirler (4) is connected to the fairing (3) through the chassis (5). A second through hole is correspondingly arranged on the chassis (5) at the connection with the duty-class swirler (4).

4. A head structure of a multi-point staged low-pollution combustion chamber based on main combustion pre-film atomization according to claim 2, characterized in that: It also includes an external fuel pipeline (1) and a cover plate (6). At positions corresponding to the main combustion stage oil passage (2-1) and the duty class swirler (4) on the cover plate (6), there is an external fuel pipeline (1), and the external fuel pipeline (1) is communicated with the main combustion stage oil passage (2-1) and the duty class swirler (4).

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