Pre-combustion-stage direct injection main combustion-stage pre-mixing and pre-evaporating three-cyclone combustion chamber
Technical Field
The invention belongs to the technical field of combustion chambers, and particularly relates to a pre-combustion-stage direct injection main combustion-stage premixing and pre-evaporating three-cyclone combustion chamber.
Background
With the increasing concern of people on the environment and health, people pay more attention to various pollution sources which are harmful to the health of themselves and damage the environment and strictly control the pollution sources. Although aircraft engines and industrial gas turbines account for a small percentage of total combustion pollutant emissions, high concentrations of pollutant emissions accumulate due to their local characteristics, such as near airports and at the sites where industrial gas turbines are used. In the air, the pollutant emissions produced by various types of aircraft are the only source of high-altitude atmospheric pollutants. As a result, emissions from gas turbines, including aircraft engines and various industrial gas turbines, are increasingly more severely limited.
The standard for the emission of pollution of civil aviation gas turbines is promulgated by the international civil aviation organization. The current environmental protection activities of the international civil aviation organization are organized by the aviation environmental protection committee and currently the CAEP6 is performed, especially with increasingly stringent emission requirements for NOx.
For industrial gas turbines and marine gas turbines, due to different laws and regulations in various countries, no unified standard exists at present, and the unified standard is established according to the requirements of the countries and the regions on environmental protection. Worldwide, southern california and japan require legislation to limit NOx emissions to 9ppmv, the so-called single digit emission, due to strong public awareness of environmental protection. The emission standards in europe are generally similar to those of the united states environmental protection agency.
In order to meet the ICAO cae standards, research into low-pollution combustion technology has been conducted by various large airlines and research institutes. The GE company develops a TAPS low-pollution combustor for a GEnx engine, the Puhui company uses an RQL mode to reduce pollutant emission and develops TALON X, and the Roro company uses an LPP combustion organization mode to reduce the NOx pollution emission index in an ICAO CAEP2 standard by more than 70%. The Roro company also develops another low-pollution combustor, ANTLE, which applies LDM low-pollution combustion mode, and the experimental result shows that the NOx pollution emission is 50% lower than the current ICAO standard.
In the field of industrial gas turbines, each large gas turbine company has developed different types of low pollution combustors. A RB211-DLE industrial low-pollution combustion chamber of Roro company adopts a two-stage premixing combustion mode, the head part is a two-stage swirler, and a staged fuel nozzle is used for controlling the flame temperature in a flame tube. The emission of NOx pollutants is less than 25ppm, the emission of CO pollutants is less than 50ppm, and the fuel oil is gas-phase fuel. A TRENT industrial low-pollution combustion chamber of Roro company adopts a three-stage premixing mode, the head part is a two-stage swirler, and a graded fuel nozzle is used for controlling the flame temperature in a flame tube. The emission of NOx pollutants is less than 25ppm, the emission of CO pollutants is less than 5ppm, and the fuel oil is gas-phase fuel. The LM2500/6000 industrial low-pollution combustor of GE company has 75 double swirlers arranged in the annular combustor, and the two-stage swirlers are arranged in opposite rotating directions and three rows in radial directions. The gaseous fuel test results showed NOx pollutant emissions of less than 25ppm and CO pollutant emissions of 10 ppm.
Although the aero-engine or the ground gas turbine solves the emission requirements of the low-pollution gas turbine to different degrees, the structure and the oil supply system are complex, the weight is too high, and aiming at the defects, the three-cyclone combustion chamber for pre-combustion stage direct injection main combustion stage premixing and pre-evaporation is provided.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a pre-combustion stage direct injection main combustion stage premixing and pre-evaporation three-cyclone combustion chamber, which adopts staged combustion, particularly adopts special structural design and arrangement mode of a first-stage axial inclined hole type cyclone and a second-stage radial inclined hole type cyclone and an oil supply mode of a main combustion stage, can realize the premixing combustion of the main combustion stage, thereby achieving the purpose of reducing the pollution emission of the combustion chamber, also simplifies the complexity of a main combustion stage oil supply system during staged oil supply, reduces the weight, and simultaneously can reduce the risk of nozzle coking when the main combustion stage fuel oil is supplied by an oil collection cavity type.
The technical scheme is as follows: the invention relates to a pre-combustion stage direct injection main combustion stage premixing and pre-evaporating three-cyclone combustion chamber which comprises a diffuser, an outer casing, an inner casing, a flame tube, a high-energy ignition electric nozzle, an oil supply pipe and a flame tube head, wherein the flame tube head consists of a pre-combustion stage and a main combustion stage;
the main combustion stage is composed of a main combustion stage direct-injection nozzle, an evaporating pipe, a second-stage radial oblique-cut hole swirler, a third-stage axial swirler and a sleeve, primary atomized fuel oil sprayed out through the main combustion stage direct-injection nozzle and air entering the evaporating pipe are subjected to shearing secondary atomization, are further evaporated and blended through the second-stage radial oblique-cut hole swirler after being evaporated and blended in the evaporating pipe, and finally are blended with air passing through the third-stage axial swirler in a secondary blending section to reach a required equivalence ratio to enter a flame tube;
the first-stage axial chamfer hole type swirler and the second-stage radial chamfer hole type swirler are of an integrated structure.
Furthermore, the first-stage axial chamfer hole type swirler and the second-stage radial chamfer hole type swirler have the same rotating direction, and the axial chamfer holes of the first-stage axial chamfer hole type swirler and the radial chamfer holes of the second-stage radial chamfer hole type swirler are arranged in a crossed manner.
Furthermore, the number of the axial chamfer holes of the first-stage axial chamfer hole type swirler is the same as that of the radial chamfer holes of the second-stage radial chamfer hole type swirler.
Furthermore, the opening shape of the axial oblique cutting hole of the first-stage axial oblique cutting hole type swirler is circular, the angle of the axial oblique cutting hole is 30-60 degrees, and the number of the axial oblique cutting holes is 6-9.
Furthermore, the radial oblique cutting hole opening shape of the second-stage radial oblique cutting hole swirler is a parallelogram, the angle of the radial oblique cutting holes is 30-60 degrees, and the number of the radial oblique cutting holes is 6-9.
Furthermore, the length of the evaporating pipe of the main combustion stage is 20-50 mm.
Furthermore, the blade installation angle of the third-stage axial cyclone is 30-45 degrees, the number of the blades is 9-16, and the rotation direction of the third-stage axial cyclone is opposite to that of the second-stage radial chamfered hole cyclone.
Further, the length of the secondary mixing section of the main combustion stage is 15-25 mm.
Has the advantages that: compared with the prior art, the invention has the following advantages:
(1) the three-cyclone combustion chamber is a graded combustion chamber, and due to the special structure and position design of the pre-combustion stage and the main combustion stage, high-efficiency low-emission combustion under wider working conditions can be realized;
(2) according to the three-cyclone combustion chamber, a fuel oil system is simpler, the head of the combustion chamber is more compact, and the weight of the combustion chamber is greatly reduced;
(3) according to the three-cyclone combustion chamber, due to the special design of the oil supply system and the cyclone, the effect of premixing and pre-evaporating main fuel oil is achieved, and the early coking of the oil supply rod, the pre-burning stage centrifugal nozzle and the main burning stage direct injection nozzle can be prevented due to the air cooling effect of the evaporation pipe.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the head structure of the flame tube;
FIG. 3 is a schematic view of the structure of the first stage of axial chamfered hole type swirler integrated with the second stage of radial chamfered hole type swirler;
FIG. 4 is a front view of FIG. 3;
fig. 5 is a left side view of fig. 3.
Detailed Description
The invention is further described below with reference to the following figures and examples:
as shown in fig. 1, the pre-combustion stage direct injection main combustion stage premixing and pre-evaporating three-swirl combustor 1 of the present invention comprises a diffuser 2, an outer casing 3, an inner casing 4, a flame tube 7, a high-energy ignition electric nozzle 8, an oil supply pipe 9 and a flame tube head 5, wherein the flame tube 7 is provided with a main combustion hole 10, a mixing hole 11 and a cooling hole 16, the flame tube head 5 is composed of a pre-combustion stage 14 and a main combustion stage 15, wherein the outer casing 3 and the inner casing 4 are main bearing parts of the combustor 1 and form an outer annular channel 12 and an inner annular channel 13 of the combustor 1 with the flame tube 7, the diffuser 2 is arranged at an inlet of the combustor 1, and mainly functions to reduce the inlet air flow rate of the flame tube 7 and improve the inlet pressure, which is beneficial to reducing loss and organizing combustion;
the air passing through the diffuser 2 is divided into three streams, one stream flows into the outer ring channel 12 through the cap 6 with minimal flow loss, one stream flows into the inner ring channel 13 with minimal flow loss, and the last stream enters the flame tube 7 through the flame tube head 5;
the method comprises the following steps that a main combustion area is formed by air in an outer ring channel 12 and an inner ring channel 13 of a combustion chamber 1 together with air passing through a flame tube head 5 through a main combustion hole 10, the air in the outer ring channel 12 and the air in the inner ring channel 13 of the combustion chamber 1 enter a flame tube 7 through a mixing hole 11, the air in the main combustion area is mixed to reach the required temperature, the air in the outer ring channel 12 and the air in the inner ring channel 13 of the combustion chamber 1 enter the flame tube 7 through a cooling hole 16, the flame tube 7 is cooled, and the flame tube wall is isolated from high-temperature fuel gas;
as shown in fig. 2, the pre-combustion stage 14 is assembled with the main combustion stage 15 in a central staged manner, with the pre-combustion stage 14 in the center and the main combustion stage 15 outside the pre-combustion stage 14; the flame tube chamber heads 5 are uniformly arranged in the circumferential direction of the whole engine, the number of the flame tube chamber heads is 16-30, the air inflow of the flame tube heads 5 accounts for 45-75% of the total air inflow of the combustion chamber 1, the pre-combustion stage 14 accounts for 15-30% of the air amount of the flame tube heads 5, and the main combustion stage 15 accounts for 70-85% of the air amount of the flame tube heads 5;
as shown in fig. 1 and fig. 2, the precombustion stage 14 is composed of a first-stage axial inclined-cut hole type swirler 231, a precombustion stage venturi 29 and a precombustion stage centrifugal nozzle 28, the precombustion stage centrifugal nozzle 28 of the precombustion stage 14 is a pressure atomizing nozzle, the atomizing taper angle is 45-120 °, and the outlet of the precombustion stage centrifugal nozzle 28 is flush with the outlet of the first-stage axial inclined-cut hole type swirler 231; the pre-combustion stage 14 adopts a single-oil-way centrifugal nozzle, and fuel oil is atomized by pressure to reach required concentration and size distribution, specifically: the fuel oil enters the pre-combustion stage oil supply rod 21 through the pre-combustion stage fuel oil pipe 18 and then enters the pre-combustion stage centrifugal nozzle 28, is atomized and evaporated by pressure and is mixed with the air passing through the first stage axial inclined hole type swirler 231 to reach the required equivalence ratio and then enters the flame tube 7;
the main combustion stage 15 is composed of a main combustion stage direct-injection nozzle 32, an evaporation pipe 22, a second-stage radial chamfered hole swirler 232, a third-stage axial swirler 24 and a sleeve 30, fuel oil of a main combustion stage fuel oil pipe 17 is sprayed out through a fuel injection hole 20 of the main combustion stage direct-injection nozzle 32, the fuel oil is sprayed to the incoming air perpendicularly and sprayed to the main combustion stage venturi tube 19 for primary atomization, the fuel oil after primary atomization is subjected to secondary atomization in the evaporation pipe 22 under the action of shearing force of air, the secondarily atomized main combustion stage fuel oil is further mixed with the air in the evaporation pipe 22 and then further evaporated and mixed through the second-stage radial chamfered hole swirler 232, and finally mixed with the air passing through the third-stage axial swirler 24 in a main combustion stage secondary mixing section 31 to reach a required equivalence ratio to enter the flame tube 7, wherein the length of the secondary mixing section 31 of the main combustion stage 15 is between 15 and 25mm, and the length of the evaporation tube 22 of the main combustion stage 15 is between 20 and 50 mm;
the first stage axial chamfered hole type swirler 231 and the second stage radial chamfered hole type swirler 232 are integrated to form a swirler 23;
because the temperature of the air entering the flame tube 7 is high, and the combustion chamber 1 works, the temperature of the head part 5 of the flame tube is overhigh through the modes of heat conduction, convection heat exchange, heat radiation and the like, and fuel oil is easy to coke in each oil pipe and nozzle, the head part of the combustion chamber 1 can well solve the problem of coking of the fuel oil at key parts through special structural design, when the pre-combustion stage 14 supplies oil and the main combustion stage 15 does not supply oil, the air passing through the evaporation pipe 22 can cool the pre-combustion stage oil supply rod 21 and the pre-combustion stage centrifugal nozzle 28, so that the coking of the fuel oil is prevented; when the pre-combustion stage 14 is supplied with oil and the main combustion stage 15 is also supplied with oil, the air entering the evaporation pipe 22 is mixed with the main combustion stage fuel oil to cool the main combustion stage direct injection nozzle 32, the pre-combustion stage fuel supply rod 21 and the pre-combustion stage centrifugal nozzle 28;
as shown in fig. 3 to 5, the first stage axial inclined hole-type swirler 231 and the second stage radial inclined hole-type swirler 232 are integrally designed to form the swirler 23 of an integrated structure, which not only provides possibility for a simpler premixing and pre-evaporation oil supply manner for the main combustion stage 15, but also reduces the weight of the flame tube head 5, facilitates disassembly and assembly, and improves the maintainability of the combustion chamber;
the first-stage axial chamfer hole type swirler 231 and the second-stage radial chamfer hole type swirler 232 have the same rotating direction, the axial chamfer holes 25 of the first-stage axial chamfer hole type swirler 231 and the radial chamfer holes 26 of the second-stage radial chamfer hole type swirler 232 are arranged in a crossed manner, the number of the axial chamfer holes 25 of the first-stage axial chamfer hole type swirler is the same as that of the radial chamfer holes 26 of the second-stage radial chamfer hole type swirler, and the angle of the axial chamfer holes 25 of the first-stage axial chamfer hole type swirler is the same as that of the radial chamfer holes 26 of the second-stage radial chamfer hole type swirler;
the opening of an axial oblique cutting hole 25 of the first-stage axial oblique cutting hole type swirler is circular, the angle of the axial oblique cutting hole 25 is 30-60 degrees, and the number of the axial oblique cutting holes 25 is 6-9; the opening shape of the radial oblique cutting holes 26 of the second-stage radial oblique cutting hole cyclone is a parallelogram, the angle of the radial oblique cutting holes 26 is 30-60 degrees, and the number of the radial oblique cutting holes 26 is 6-9;
the installation angle of the blades 27 of the third-stage axial cyclone 24 is 30-45 degrees, the number of the blades 27 is 9-16, and the rotation direction of the third-stage axial cyclone 24 is opposite to that of the second-stage radial chamfered hole cyclone 232.