CN102242939B - Prefilming three-stage pre-mixing and pre-evaporating low-pollution combustor - Google Patents

Abstract

A pre-film type low-pollution combustion chamber with three stages of premixing and pre-evaporation, including a diffuser, a casing outside the combustion chamber, a casing inside the combustion chamber, the outer wall of the flame tube, the inner wall of the flame tube, and the head of the combustion chamber; all air used for combustion is Entering the flame cylinder from the head of the combustion chamber, a staged combustion scheme is adopted, which is divided into a pre-combustion stage and a main combustion stage; The structure of the main combustion stage is divided into two stages, which avoids the increase of pollution emissions caused by the poor oil-gas mixing of the main stage when the main stage is changed to one stage, and reduces the working condition by 30% without affecting stable combustion emissions of pollutants. The second stage of the main combustion stage adopts pre-film nozzles to make the fuel distribution more uniform, and further reduce pollutants under large working conditions compared with discrete nozzles. The invention reduces the pollution emission of the whole landing and take-off cycle of the aero-engine combustion chamber without affecting the combustion stability.

Description

A pre-film type low-pollution combustor with three stages of pre-mixing and pre-evaporation

technical field

The invention relates to a low-pollution combustor of an aviation gas turbine utilizing premixed pre-evaporative combustion technology. The staged combustion mode is adopted, and the main combustion stage adopts the premixed combustion method, which is mainly used to reduce pollution emissions under large working conditions; the pre-combustion stage adopts the diffusion combustion method to ensure stable combustion in the combustion chamber, and the main combustion stage uses two The way of pre-mixed pre-evaporative combustion can reduce the pollution emission of the entire LTO cycle of the aero-engine.

Background technique

The basic performance and structural distribution of modern aero-engine combustors have reached a fairly high level, but there are still a lot of problems and challenges for modern aero-engine combustors. The development and application of new materials, new processes, new structures, and new concepts It is the source to ensure its continuous progress.

The main development trend of modern civil aeroengine combustors is low-pollution combustion. Combustion chambers of civil aeroengines must meet increasingly stringent aeroengine pollution emission standards. The currently adopted CAEP6 (Committee on Aviation Environmental Protection) standard has very strict regulations on pollutant emissions, especially the requirements for NOx pollution emissions; and the latest CAEP8 standard proposes to reduce NOx emissions by 15% from the CAEP6 emission standards , with the rapid development of the aviation industry and the continuous improvement of people's awareness of environmental protection, higher requirements will be put forward for the pollution emissions of gas turbine combustors in the future.

GE and PW, two well-known American aero-engine companies, have already started research on low-pollution combustion chambers. GE first developed a double-ring cavity low-pollution combustion DAC (for GE90 and CFM56), and PW company adopted RQL (oil-rich combustion-quenching -Rich burn-Quench-Lean burn, RQL) low-pollution combustor TALON II (for PW4000 and 6000 series). In terms of the next generation of low-pollution combustors, GE uses LDM (Lean Direct Mixing Combustion, Lean Direct Mixing Combustion) technology to develop the TAPS (Twin Annular Premixing Swirler) low-pollution combustor for its GEnx engine. In the bench full ring test verification of the combustion chamber, the NOx pollution emission is reduced by 50% compared with the CAEP2 emission standard. GE has applied for a number of U.S. patents: application numbers 6363726, 6389815, 6354072, 6418726, 0178732, 6381964 and 6389815. All of these patents use diffusion combustion in the pre-combustion stage and premixed combustion in the main combustion stage. It is to reduce the NOx emission under the large working condition with the largest emission index. PW Company continues to adopt the RQL method and proposes a low-pollution combustion chamber that reduces NOx pollution emissions as TALON X. The head form used is the air atomizing nozzle developed by PW Company. The combustion chamber is a single annular cavity. In the fan-shaped test section of the V2500 engine The above test results are 50% lower than the CAEP2 standard. The low-pollution combustor developed by Rolls-Royce using LDM technology is ANTLE, which is a single-annular staged combustor. Its NOx pollution emissions are 50% lower than CAEP2 standards, and it is used in its new generation of engines with turbulence up to 1000.

China's Beijing University of Aeronautics and Astronautics has also applied for a number of patents such as 200910238793.X, 201010101574.X, 201010034141.7, 201010277014.X and other low-pollution combustion chambers. The scheme adopted is that the pre-combustion stage adopts the diffusion combustion method, and the main combustion stage adopts premixing Combustion mode, the main combustion stage is a ring structure, axial or radial oil supply, using multi-point injection or pre-film atomization, the purpose is to reduce NOx emissions under large working conditions, so that the NOx emissions of the entire LTO cycle However, it is difficult to further reduce the NOx emission level of the whole LTO cycle.

The above-mentioned patents are all aimed at reducing pollution emissions under large working conditions, and according to the emission index under a standard cycle stipulated by the International Civil Aviation Organization (International Civil Aviation Organization, ICAO), this parameter is expressed by LTO Emission, The calculation is as follows:

$\mathrm{<span\; class="notranslate">\; LTO\; Emission</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; kN</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; oo</span>}}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; EI</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; mf</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; oo</span>}}}$

It can be seen from the above formula that LTO Emission is related to NOx emissions under four working conditions, that is, not only related to NOx emissions under large working conditions, but also related to NOx emissions under small working conditions.

The operating modes in the standard LTO cycle, the thrust and operating time in each operating mode, are shown in the table below.

Table 1 Operation modes and times in the LTO cycle specified by ICAO

operating mode thrust setting running time (min) Take-off 100% F _oo 0.7 Climb 85% F _oo 2.2 Approach 30% F _oo 4.0 Taxi/ground idle 7% F _oo 0

The NOx emissions of CFM56-5B/3 engines with a thrust of 140KN in conventional or active service are shown in the table below, and the data comes from ICAO Emission data bank.

Table 2 NOx emission levels of CFM56-5B/3

parameter unit local approach to climb take off Emission Index (EI) g/(kgf) 4.45 9.28 19.77 26.18 fuel flow kg/s 0.112 0.448 1.086 1.325

operation hours g 1560 240 132 42 emissions g/kN 777.5 997.8 2834.1 1456.9

The combustion chamber adopts staged combustion, the pre-combustion stage adopts the diffusion combustion method, and the main combustion stage adopts the pre-mixed combustion method, which reduces NOx emissions under large working conditions. The NOx emissions that can be achieved are shown in the following table:

Table 3 NOx emission levels that can be achieved by premixed combustion in the main combustion stage

parameter unit local approach to climb take off NOx emission index (EI) g/(kgf) 4.45 9.28 4 4.1 fuel flow kg/s 0.112 0.448 1.086 1.325 operation hours g 1560 240 132 42 emissions g/kN 777.5 997.8 594 228

Under small working conditions (ground idle, approach), although the NOx emission index is low, it can be seen from Table 1 that the running time under small working conditions is much higher than other large working conditions. According to Table 3, when the main combustion stage adopts When the co-combustion mode is used, the NOx emission index under large working conditions can be greatly reduced. At this time, the total NOx emission of the pre-combustion stage accounts for the largest proportion in the pollution emission of the entire LTO cycle. Therefore, in order to further reduce the overall For the NOx emission of the LTO cycle, it is necessary to consider reducing the NOx emission of the pre-combustion stage.

No matter what kind of advanced low-pollution combustion chamber, its key technology is to reduce NOx (nitrogen oxides), CO (carbon monoxide), UHC (unburned hydrocarbons) and smoke combustion technology, the core issue is to reduce the combustion area At the same time, the temperature field in the combustion zone is uniform, that is, the overall and local equivalence ratio is controlled, and the uniformity of the equivalence ratio in the main combustion zone mainly depends on the uniformity of fuel atomization and oil-gas mixing.

The invention is a new method for low-pollution combustion of aero-engines. According to the mechanism and test results of NOx and CO production, it can be known that the equivalent ratio of the main combustion zone of the combustion chamber produces very little NOx and CO (the emission laws of UHC and CO are similar). Based on this principle, to take into account that the emissions of NOx, CO, and UHC are all in the low range, two factors should be considered: one is the average equivalence ratio of the main combustion zone, and the other is the uniformity of the average equivalence ratio of the main combustion zone. And this should be the case in all aero-engine work situations. The uniformity of the equivalence ratio in the main combustion zone mainly depends on the uniformity of fuel atomization and oil-gas mixing. This mainly depends on two aspects: one is the uniformity of fuel particle diameter distribution, that is, the uniformity of SMD distribution; the other is the uniformity of fuel oil mist concentration distribution. In terms of the combustion method, uniform premixed combustion should be adopted to meet the requirements of uniformity ratio of the main combustion zone to reduce pollution emissions.

The current conventional combustion methods cannot reduce NOx, CO and UHC. The reason is determined by the current design method of the combustion chamber. For conventional combustors, in the large state, due to the liquid mist diffusion combustion method, the local equivalence ratio of the combustion zone is always around 1, which far exceeds the range of equivalence ratio required for low-pollution combustion. At this time, although CO and UHC The emission is low, but the emission of NOx reaches the maximum. In the small state, the equivalence ratio of the combustion zone is very low, far below the equivalence ratio range required for low-pollution combustion. At this time, although NOx emissions are low, CO and UHC emissions are high. In addition, because the conventional combustion chamber generally adopts the diffusion combustion method, the local equivalence ratio is not uniform, so for the conventional combustion chamber, it cannot meet the low pollution requirements in the entire engine working range.

Contents of the invention

The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art and to provide a pre-film type low-pollution combustion chamber with three stages of pre-mixing and pre-evaporation by using the premixed pre-evaporation combustion technology. The main combustion stage of the combustion chamber The pre-mixed combustion method is adopted, which can maintain low pollution emissions above 30% of the working conditions; the pre-combustion stage adopts the diffusion combustion method, which can ensure the stable operation of the engine under small working conditions, thereby reducing the pollution in the entire LTO cycle emission.

The technical solution adopted by the present invention to solve the technical problem is: the pre-combustion stage adopts the method of diffusion combustion, and the main combustion stage adopts the method of premixed combustion in two stages. The combustion chamber adopts a single-ring cavity structure, and its outer contour is composed of an outer casing of the combustion chamber and an inner casing of the combustion chamber; outside air enters through a diffuser, and the outer wall of the flame cylinder, the inner wall of the flame cylinder and the head of the combustion chamber form a combustion area. All the combustion air enters the flame tube from the head of the combustion chamber, and the mixed air is injected from the outer mixing hole on the outer wall of the flame tube and the inner mixing hole on the inner wall of the flame tube; the head of the combustion chamber adopts a staged combustion scheme, It is divided into main combustion stage and pre-combustion stage. The outer ring of the main combustion stage is connected and fixed with the outer wall of the flame tube and the inner wall of the flame tube through the overall end wall of the head. The inner ring cavity of the main combustion stage is integrated with the fuel nozzle; The end wall of the stage head is connected with the main combustion stage, and is concentric with the main combustion stage; The low-velocity recirculation area generated by the swirling air of the pre-combustion stage swirler assembly entering the combustion chamber stabilizes the flame, and the pre-combustion stage swirler assembly is connected to the inner ring of the pre-mixing pre-evaporation section of the main combustion stage through the end wall of the pre-combustion stage head ; The pre-combustion stage nozzle is located in the pre-combustion stage swirler assembly and is coaxial with the pre-combustion stage swirler assembly; the end wall of the pre-combustion stage head is connected to the inner ring of the pre-combustion stage premixing evaporation section and the outer ring of the pre-combustion stage On the ring pipe; wherein the pre-combustion level swirler includes the pre-combustion level outer ring pipe, the pre-combustion level Venturi tube, the pre-combustion level swirler vane; The inner ring of the evaporation ring, the main fuel oil ring, the inner ring of the pre-film nozzle, the outer ring of the pre-film nozzle, the outer swirler of the main combustion stage, the inner swirler of the main combustion stage and the inner swirler of the pre-film nozzle , where the main combustion stage inner swirler is welded with the pre-film nozzle inner ring and the premixing pre-evaporation ring inner ring to form the main combustion stage inner ring chamber, the main combustion stage outer swirler and the premixing pre-evaporation ring The outer ring together constitutes the outer ring of the main combustion stage, and the outer ring of the pre-film nozzle forms the outer ring cavity of the main combustion stage. The inner and outer ring chambers of the main stage are combined into a premixing section after the pre-film nozzle; All fuel is supplied, and the fuel nozzles include pre-combustion stage nozzles, main combustion stage inner nozzles and pre-film nozzles, and the fuel nozzles are directly inserted into the main combustion stage outer ring from the upstream of the combustion chamber head; the pre-combustion stage nozzles are single nozzles, Directly inserted into the inner channel downstream of the positioning ring of the pre-combustion stage nozzle, the fuel passing through the pre-combustion stage fuel pipeline forms a pre-combustion stage oil mist through the pre-combustion stage nozzle, and the pre-combustion stage oil mist hits the pre-combustion stage cyclone Venturi The oil film is formed on the inner wall of the tube, which is atomized under the action of the incoming flow through the inner channel of the pre-combustion stage, and diffused combustion is carried out at the outlet of the pre-combustion stage; The inner fuel ring of the main combustion stage and the inner ring of the premixing pre-evaporation ring together form the inner channel of the main combustion stage fuel, which is a ring structure; the inner ring of the premixing pre-evaporation ring is uniformly opened with multiple main combustion stages along the circumferential direction Inner direct-injection injection holes, the fuel enters the main combustion-stage fuel channel through the main-stage internal fuel pipe, and then passes through the main-stage internal direct-injection injection holes to form multiple main-stage inner-ring sprays, which are sprayed toward the premixing section; the main-stage inner ring The oil mist is evaporated and premixed under the action of the internal swirling flow of the main combustion stage, and the fuel is quickly evaporated and mixed with air in a relatively short geometric size, and then enters the outlet of the main combustion stage through the premixing section for pre-mixing. Co-combustion ensures low pollution The pre-film nozzle is composed of the pre-film nozzle inner ring, the pre-film nozzle outer ring and the pre-film swirler; the fuel passes through the pre-film nozzle and the pre-film swirler to form a layer of uniform main combustion The oil film of the main fuel stage is injected into the premixing section; the oil film of the main fuel stage is evaporated and premixed and mixed under the action of the internal and external swirling flow of the main fuel stage, and the fuel is quickly evaporated and mixed with the air in a relatively short geometric size, and then passed through The premixing section enters the outlet of the main combustion stage for premixed combustion to ensure lower pollution emissions.

The principle of the invention is as follows: the purpose of reducing pollution discharge is achieved by controlling the equivalence ratio and uniformity of the combustion zone in the combustion chamber of the aero-engine. All the air for combustion enters the flame tube from the head of the combustion chamber, so that most of the fuel and air are mixed evenly before entering the flame tube for combustion, which is beneficial to controlling the equivalent ratio of the combustion zone and reducing pollution emissions. The staged combustion scheme is adopted. Under small working conditions, only the pre-combustion stage works for fuel supply. Combustion level common oil supply work. Under small working conditions, only the pre-combustion stage fuel supply works, and the pre-combustion stage fuel burns at the pre-combustion stage outlet through the pre-combustion stage nozzle, which is a diffusion combustion method; since the pre-combustion stage outlet is a strong recirculation zone, diffusion combustion The pre-combustion grade fuel burns in this strong recirculation zone, thus ensuring the stability of combustion; under the intermediate working condition, the main combustion stage and the pre-combustion stage are supplied with fuel at the same time, and the primary fuel oil of the main combustion stage enters the swivel nozzle through the direct injection nozzle. The air channel of the flow device is pre-evaporated and mixed with air under the action of swirling flow, and participates in combustion at the outlet of the main combustion stage. It is a pre-mixed combustion method to avoid the failure of the main combustion stage due to the consideration of large working conditions when the main combustion stage is not classified. The flow rate of the main combustion stage is too large, resulting in poor atomization and mixing in the intermediate working conditions, so as to ensure the pollution discharge in the intermediate working conditions. Under heavy working conditions, the main combustion stage and the pre-combustion stage work at the same time, and the fuel flow of the main combustion stage accounts for most of the fuel flow. Co-combustion enables the equivalent ratio of the combustion zone to be within the range of low pollution emissions, thereby controlling pollution emissions under large working conditions. Therefore, this type of combustor ensures that the aeroengine has low pollution emissions in a wide operating range, thereby further reducing NOx emissions under the entire LTO cycle, while ensuring combustion stability.

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

(1) The pre-combustion stage of the present invention adopts a combustion method combining diffusion combustion and premixed combustion, and achieves the purpose of coexistence of the two combustion methods by dividing the fuel into three stages. Pollutant emissions under all working conditions.

(2) The main combustion stage is divided into two stages, which avoids the increase of pollution emissions caused by the poor oil-gas mixing of the main stage when the main combustion stage is one-stage, and can reduce the pollution emissions under large and small working conditions. Pollution emissions are reduced at the same time, thereby further reducing the pollution emissions of the entire LTO cycle.

(3) The second stage of the main combustion stage adopts pre-film nozzles to make the fuel oil distribution more uniform and further reduce pollutant emissions.

(4) The present invention adopts a single-annular combustion chamber structure, and all the air for combustion is supplied from the head. There are only mixing holes and necessary cooling holes on the flame tube, which has modular features and simplifies the combustion chamber structure. The main combustion stage And pre-combustion level structure is relatively simple, easy to process.

Description of drawings

Figure 1 is a schematic diagram of the engine structure;

Fig. 2 is a sectional view of the combustion chamber structure of the present invention;

Fig. 3 is a cross-sectional view of the combustion chamber head structure of the present invention;

Fig. 4 is a cross-sectional view of the pre-combustion stage structure of the present invention;

Figure 5 is a sectional view of the head structure of the present invention (not including the nozzle rod);

Fig. 6 is a sectional view of the fuel nozzle structure of the present invention;

Fig. 7 is a sectional view of the outer ring of the main combustion stage of the present invention;

Fig. 8 is a sectional view of the center section (A-A section) of the direct injection hole in the main combustion stage of the present invention;

Among them, 1 is the low-pressure compressor, 2 is the high-pressure compressor, 3 is the combustion chamber, 4 is the high-pressure turbine, 5 is the low-pressure turbine, 6 is the casing outside the combustion chamber, 7 is the casing inside the combustion chamber, 8 is the outer wall of the flame tube, and 9 is The inner wall of the flame tube, 10 is the diffuser, 11 is the mixing hole on the outer wall of the flame tube, 12 is the mixing hole on the inner wall of the flame tube, 13 is the head of the combustion chamber, 14 is the main combustion stage, 15 is the pre-combustion stage, and 16 is the fuel oil Nozzle, 17 is pre-combustion level oil mist, 18 is main combustion level inner ring oil mist, 19 is main combustion level oil film, 20 is pre-combustion level swirler assembly, 21 is pre-combustion level nozzle, 22 is pre-combustion level head 23 is the pre-combustion level outer ring pipe, 24 is the pre-combustion level venturi tube, 25 is the pre-combustion level swirler vane, 26 is the pre-combustion level nozzle positioning ring, 27 is the pre-combustion level inner channel, 28 29 is the inner wall of the pre-combustion venturi tube, 30 is the outlet of the pre-combustion level, 31 is the outer ring of the pre-mixing pre-evaporation ring, 32 is the pre-film nozzle swirler, and 33 is the pre-mixing pre-evaporation ring. The inner ring of the evaporation ring, 34 is the outer swirler of the main combustion stage, 35 is the inner swirler of the main combustion stage, 36 is the outer ring cavity of the main combustion stage, 37 is the inner ring cavity of the main combustion stage, 38 is the premixing section, 39 40 is the inner nozzle of the main combustion stage, 41 is the pre-film nozzle, 42 is the inner ring of the pre-film nozzle, 43 is the outer ring of the pre-film nozzle, 44 is the outer ring of the main combustion stage, and 45 is the main 46 is the internal fuel pipe of the main combustion stage, 47 is the outer fuel pipe of the main combustion stage, 48 is the internal fuel oil ring of the main combustion stage, 49 is the outlet of the main combustion stage, 50 is the inner injection hole of the main combustion stage, 51 is the overall end wall of the head.

Detailed ways

FIG. 1 is a schematic structural diagram of an engine, including a low-pressure compressor 1 , a high-pressure compressor 2 , a combustion chamber 3 , a high-pressure turbine 4 and a low-pressure turbine 5 . When the engine is working, the air is compressed by the low-pressure compressor 1 and enters the high-pressure compressor 2. The high-pressure air then enters the combustion chamber 3 to burn with fuel. The high-temperature and high-pressure gas formed after combustion enters the high-pressure turbine 4 and low-pressure turbine 5, and passes through the turbine. Work is done to drive the high-pressure compressor 2 and the low-pressure compressor 1 respectively.

As shown in Figure 2, the combustion chamber 3 adopts a single-ring cavity structure, and the outer casing 6 and the inner casing 7 of the combustion chamber form the outer contour of the combustion chamber, and are connected with the high-pressure compressor 2 and the high-pressure turbine 4 before and after. The incoming air from the high-pressure compressor 2 enters the combustion chamber from the diffuser 10 through reduced-speed diffusion, and burns with the fuel in the space surrounded by the outer wall 8 of the flame tube, the inner wall 9 of the flame tube and the head 13 of the combustion chamber. The area before the outer mixing hole 11 and the inner mixing hole 12 is the combustion zone. The mixed air enters the flame tube from the mixing hole and mixes with the high-temperature gas in the combustion zone to make the outlet temperature meet the design requirements. The combustion chamber head 13 includes a main combustion stage 14, a pre-combustion stage 15 and a fuel nozzle 16. The main combustion stage 14 is welded and fixed to the outer wall 8 of the flame tube and the inner wall 9 of the flame tube through the integral end wall 51 of the head, while the pre-combustion stage 15 is The head end wall 22 of the pre-combustion stage is fixedly connected with the main combustion stage 14, and the fuel nozzle 16 supplies all the fuel. The combustion chamber head 13 is evenly arranged along the circumference, and the number is 10 to 60. The air volume of the combustion chamber head 13 accounts for 20% to 80% of the total air volume of the combustion chamber, and the main combustion stage 14 accounts for the total air volume of the combustion chamber. 60% to 90% of the air volume, and the pre-combustion stage 15 accounts for 10% to 40% of the head air volume.

Fig. 3 is a sectional view of the head structure of a combustion chamber, it can be clearly seen that the main combustion stage 14 and the pre-combustion stage 15 are arranged concentrically together. FIG. 4 is a cross-sectional view of the structure of the pre-combustion stage. It can be seen from FIG. 4 that the pre-combustion stage 15 is composed of a pre-combustion stage swirler 20 . It can be seen from Fig. 4, Fig. 5 and Fig. 6 that the pre-combustion stage swirler 20 is a vane type swirler or a channel type swirler, and the structure of the swirler can be an axial swirler or a radial swirler. Cyclone. When the pre-combustion stage cyclone 20 adopts a single-stage cyclone, it is directly connected with the end wall 22 of the pre-combustion stage head; when the pre-combustion stage cyclone 20 adopts a multi-stage cyclone, the cyclones connected as a whole to form a pre-combustion stage swirler 20 and then connected to the end wall 22 of the pre-combustion stage head. The connection between the pre-combustion stage swirler 20 and the end wall 22 of the pre-combustion stage head is achieved by welding or threaded locking. The pre-combustion stage swirler 20 includes a pre-combustion stage outer ring pipe 23 , a pre-combustion stage venturi tube 24 , and a pre-combustion stage swirler vane 25 . The pre-combustion stage swirler blades 25 are evenly arranged circumferentially and welded thereon, thereby connecting the pre-combustion stage outer ring pipe 23 and the pre-combustion stage venturi tube 24 together, and the blades of the pre-combustion stage swirler blades 25 are installed The angle is 30°～70°. The pre-combustion level nozzle 21 is a single pressure atomization nozzle, pneumatic atomization nozzle or combined nozzle, which is directly inserted into the inner channel 27 downstream of the pre-combustion level nozzle positioning ring 26, and the fuel passing through the pre-combustion level fuel pipeline 28 passes through the pre-combustion level nozzle. The stage nozzle 21 forms a pre-combustion stage oil mist 17, and the pre-combustion stage oil mist 17 hits the inner wall surface 29 of the venturi tube of the pre-combustion stage cyclone to form an oil film, which is atomized under the action of the incoming flow through the pre-combustion stage inner channel 27 , Diffusion combustion is carried out at the outlet 30 of the pre-combustion stage.

As can be seen from Fig. 3, Fig. 5 and Fig. 6, the main combustion stage 14 is composed of a premixed pre-evaporation outer ring 31, a premixed pre-evaporation ring inner ring 33, a main combustion stage fuel ring 48, a pre-film nozzle inner ring 42, The pre-film nozzle outer ring 43, the main combustion stage outer swirler 34, the main combustion stage inner swirler 35 and the pre-film nozzle inner swirler 32, wherein the main combustion stage inner swirler 35 and the pre-film type The nozzle inner ring 42 and the premixed pre-evaporation ring inner ring 33 are welded together to form the main combustion stage inner ring cavity 37, and the main combustion stage outer swirler 34 together with the premixing pre-evaporation ring outer ring 31 constitutes the main combustion stage outer ring cavity 37. The ring 44 and the pre-film nozzle outer ring 43 constitute the main combustion stage outer annular chamber 36, and the main stage inner and outer annular chambers 36 are merged into a premixing section 38 after the pre-film nozzle; the main combustion stage internal combustion stage 15 adopts The swirler 35 and the external swirler 34 of the main combustion stage are blade-type swirlers, and the installation angle of the blades is 30°-70°. The structure of each stage of the vane swirler is an axial swirler or a radial swirler, and the two stages have the same or opposite directions of rotation.

As can be seen from Fig. 6, the fuel nozzle 16 supplies all the fuel to the combustion chamber. Inserted upstream directly into the main stage outer ring 44 .

As can be seen from Fig. 6 and Fig. 8, the main combustion stage inner nozzle 40 is composed of the main combustion stage fuel oil inner channel 45 and the main combustion stage inner direct injection nozzle 50, and the main combustion stage inner fuel oil ring 48 and the premixing pre-evaporation ring The rings 33 together form the inner channel 45 of the main combustion stage fuel oil, which is an annular structure. The inner ring 33 of the premixing pre-evaporating ring is evenly opened with a plurality of direct-injection nozzle holes 50 in the main combustion stage along the circumferential direction. The direct injection holes 50 form a plurality of main combustion stage inner ring sprays 18 , which are sprayed into the main combustion stage inner ring cavity 37 . The pre-film nozzle 41 is composed of the pre-film nozzle inner ring 42, the pre-film nozzle outer ring 43 and the pre-film swirler 32; Evaporation, premixing and blending are carried out under the action of the flow, so that the fuel can be quickly evaporated and evenly mixed with air in a short geometric size, and then enter the outlet 49 of the main combustion stage for premixed combustion to ensure lower pollution emissions.

The number of direct-injection injection holes 50 in the main combustion stage is 6 to 30, the ratio of the number of swirler 35 blades in the main combustion stage to the number of direct-injection injection holes is 1:1 to 5:1, and the main combustion stage The inclination angles formed by the direct injection nozzle holes 50 in the stage and the wall surface of the inner ring 33 of the premixed pre-evaporation ring are both 10°-90°. The axial position of the direct injection hole is in or downstream of the inner vane channel of the main combustion stage, and the axial distance from the outlet of the main combustion stage is 20-50mm. The axial distance between the outlet of the pre-film nozzle 41 and the outlet 49 of the main combustion stage is 20 to 50mm, and the outer ring 31 of the main stage premixed pre-evaporation ring and the inner ring 33 of the pre-mixed pre-evaporation ring can be cut with tangential grooves. The inclination angles formed by the grooves and the walls of the inner and outer rings 31 and 33 of the premixing preevaporation ring are both 10°-90°, and the axial distance between the axial position and the outlet 49 of the main combustion stage is 20-50 mm. The main combustion grade fuel oil accounts for 50% to 90% of the total fuel oil.

Claims (10)

1. a pre-membrane type divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: described combustion chamber adopts the monocycle cavity configuration, and it forms its outline by casing (7) in outer combustion case (6) and combustion chamber, outside air enters by diffuser (10), burner inner liner outer wall (8), burner inner liner inwall (9) and head of combustion chamber (13) form combustion zone, combustion air all enters burner inner liner by head of combustion chamber (13), and dilution air is injected by the outer blending hole (11) on burner inner liner outer wall (8) and the interior blending hole (12) on burner inner liner inwall (9), described head of combustion chamber (13) adopts the fractional combustion scheme, is divided into main combustion stage (14) and pre-combustion grade (15), described pre-combustion grade (15) is connected with main combustion stage (14) by pre-combustion grade head end wall (22), and concentric with main combustion stage (14), pre-combustion grade (15) outwards comprises pre-combustion grade nozzle (21), pre-combustion grade swirler assembly (20), pre-combustion grade head end wall (22) by center, pre-combustion grade nozzle (21) and pre-combustion grade swirler assembly (20) coordinate location, pre-combustion grade nozzle (21) is positioned at pre-combustion grade swirler assembly (20), and coaxial with pre-combustion grade swirler assembly (20), pre-combustion grade swirler assembly (20) is connected with pre-combustion grade head end wall (22), the low speed recirculating zone that pre-combustion grade (15) utilization enters the rotational flow air generation of combustion chamber by pre-combustion grade swirler assembly (20) stabilizes the flame, and pre-combustion grade swirler assembly (20) is connected by ring (33) in pre-combustion grade head end wall (22) and main combustion stage premix and pre-evaporation section, pre-combustion grade head end wall (22) is connected in main combustion stage premix evaporator section to be encircled on (33) and the outer endless tube (23) of pre-combustion grade, wherein pre-combustion grade cyclone (20) comprises the outer endless tube (23) of pre-combustion grade, pre-combustion grade Venturi tube (24), pre-combustion grade swirler blades (25), pre-combustion grade nozzle locating ring (26), pre-combustion grade swirler blades (25) connects the outer endless tube (23) of pre-combustion grade, pre-combustion grade Venturi tube (24), pre-combustion grade nozzle locating ring successively, pre-combustion grade swirler blades (25) circumferentially is evenly arranged and is welded thereon, thereby the outer endless tube (23) of pre-combustion grade and pre-combustion grade Venturi tube (24) are linked together, described main combustion stage (14) is by premix and pre-evaporation ring outer shroud (31), ring (33) in the premix and pre-evaporation ring, main combustion stage fuel oil ring (48), ring (42) in pre-membrane type nozzle, pre-membrane type nozzle outer shroud (43), the outer cyclone (34) of main combustion stage, main combustion stage inward eddy device (35) and pre-membrane type nozzle inward eddy device (32) form, wherein in main combustion stage inward eddy device (35) and pre-membrane type nozzle, encircle (42), in the premix and pre-evaporation ring, ring (33) links together and forms ring cavity (37) in main combustion stage, the outer cyclone (34) of main combustion stage links together and forms main combustion stage outer shroud (44) with premix and pre-evaporation ring outer shroud (31), main combustion stage outer shroud (44) and pre-membrane type nozzle outer shroud (43) have formed the outer ring cavity (36) of main combustion stage, in the outer ring cavity (36) of main combustion stage and main combustion stage, ring cavity (37) is merged into premix section (38) after pre-membrane type nozzle, main combustion stage outer shroud (44) is connected and fixed by the whole end wall of head (51) and burner inner liner outer wall (8) and burner inner liner inwall (9), and in main combustion stage, ring cavity (37) and fuel nozzle (16) are integrated, described fuel nozzle (16) is supplied with all fuel oils to combustion chamber, fuel nozzle (16) outwards comprises pre-combustion grade nozzle (39), main combustion stage inner nozzle (40) and pre-membrane type nozzle (41) by center, pre-combustion grade nozzle (39) is connected with pre-combustion grade nozzle locating ring (26), and pre-membrane type nozzle (41) and main combustion stage outer shroud (44) coordinate location, fuel nozzle (16) directly inserts main combustion stage outer shroud (44) from the upstream of head of combustion chamber (13), wherein pre-combustion grade nozzle (21) is single-nozzle, directly be inserted into pre-combustion grade nozzle locating ring (26) downstream internal channel (27) inner, fuel oil through pre-combustion grade fuel pipe (28) forms pre-combustion grade mist of oil (17) by pre-combustion grade nozzle (21), pre-combustion grade mist of oil (17) is beaten at the upper oil film that forms of pre-combustion grade cyclone Venturi tube internal face (29), carry out atomization under the incoming flow effect through pre-combustion grade internal channel (27), in pre-combustion grade outlet (30), carry out diffusion combustion, main combustion stage inner nozzle (40) is comprised of direct projection spray orifice (50) in fuel gallery in main combustion stage (45) and main combustion stage, be fixed in ring (33) inboard in the premix and pre-evaporation ring, encircle (33) main combustion stage fuel oil internal channel (45) of looping structure together in main combustion stage internal combustion oil ring (48) and premix and pre-evaporation ring, in the premix and pre-evaporation ring, ring (33) is upper along circumferentially evenly having direct projection spray orifice (50) in a plurality of main combustion stages, fuel oil enters main combustion stage fuel gallery (45) by fuel pipe (46) in main combustion stage, then pass through direct projection spray orifice (50) in main combustion stage and form ring spray mist (18) in the multiply main combustion stage, spray to premix section (38), in main combustion stage, ring mist of oil (18) evaporates and the premix blending under the effect of main combustion stage inward eddy, realize the fuel oil rapid evaporation and with the even blending of air, then pass through premix section (38) and enter main combustion stage outlet (49) and carry out premixed combustion, guarantee lower disposal of pollutants, pre-membrane type nozzle (41) is comprised of ring (42), outer shroud (43) and pre-membrane type cyclone (32) in pre-membrane type nozzle, and in pre-membrane type nozzle, ring (42) and pre-membrane type nozzle outer shroud (43) are connected to form circumferential weld, and pre-membrane type cyclone is embedded in circumferential weld, fuel oil forms the even main combustion stage oil film of one deck (19) by pre-membrane type nozzle (41) through pre-membrane type cyclone (32) and sprays to premix section (38), under the effect of main combustion stage oil film (19) eddy flow inside and outside main combustion stage, evaporate and the premix blending, realize the fuel oil rapid evaporation and with the even blending of air, then pass through premix section (38) and enter main combustion stage outlet (49) and carry out premixed combustion, guarantee lower disposal of pollutants.

2. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: described pre-combustion grade nozzle (21) is pressure atomized fog jet, pneumatic nozzle or combined nozzle.

3. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: described pre-combustion grade cyclone (20) blades installation angle is 30 °～70 °, and the progression n of pre-combustion grade cyclone (20) is 1≤n≤3; The structure of every grade blade formula cyclone is axial swirler, or radial swirler; When pre-combustion grade cyclone (20) progression n=1, pre-combustion grade cyclone (20) directly connects with the whole end wall of pre-combustion grade head (22); When pre-combustion grade cyclone (20) progression n ﹥ 1, vane type cyclones at different levels first connect into an integral body, after composition pre-combustion grade cyclone (20), with pre-combustion grade head end wall (22), are connected again.

4. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: the required whole fuel oils in described fuel nozzle (16) supply combustion chamber, the ratio that the main combustion stage fuel oil accounts for total amount of fuel is 50%～90%.

5. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: the outer cyclone (34) of described main combustion stage inward eddy device (35) and main combustion stage is the vane type cyclone, and the blades installation angle is 30 °～70 °; The structure of every grade blade formula cyclone is axial swirler, or radial swirler, and the two-stage rotation direction is identical or contrary.

6. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: in described main combustion stage, the number of direct projection spray orifice (50) is 6～30, and in the number of main combustion stage inward eddy device (35) blade and main combustion stage, the ratio of the number of direct projection nozzle opening (50) is 1:1～5:1.

7. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: encircling the formed inclination angle of (33) wall in described main combustion stage in direct projection spray orifice (50) and premix and pre-evaporation ring and be 10 °～90 °, is 1:2～1:5 with the valid circulation area ratio of corresponding fuel gallery (45); In described main combustion stage, direct projection spray orifice (50) axial location is 20～50mm apart from the axial distance of main combustion stage outlet (49).

8. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: described pre-membrane type nozzle (41) outlet axial location is 20～50mm apart from the axial distance of main combustion stage outlet (49).

9. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: in described main premix and pre-evaporation ring outer shroud (31), premix and pre-evaporation ring, on ring (33), open tangential slot, in tangential slot and main premix and pre-evaporation ring outer shroud (31), premix and pre-evaporation ring, the ring formed inclination angle of (33) wall is 10 °～90 °, and axial location is 20～50mm apart from the axial distance of main combustion stage outlet (49).

10. a kind of pre-membrane type according to claim 1 divides the low pollution combustor of three grades of premix and pre-evaporations, it is characterized in that: described head of combustion chamber (13) is along circumferentially being evenly arranged, number is 10～60, the air capacity of head of combustion chamber (13) accounts for 20%～80% of combustion chamber total air, wherein main combustion stage (14) accounts for 60%～90% of head air capacity, and pre-combustion grade (15) accounts for 10%～40% of head air capacity.

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