CN113898975B - Low-emission backflow combustion chamber adopting axial staged combustion - Google Patents

Abstract

The invention discloses a low-emission backflow combustion chamber adopting axial staged combustion, which belongs to the technical field of aero-engines and comprises: the device comprises a combustion chamber casing, a flame tube bent pipe, a flame tube head, an ignition fuel nozzle, a premixing swirler and a working fuel nozzle; the flame tube elbow is arranged in the combustion chamber casing, the head of the flame tube is arranged at the head end of the flame tube elbow, the two ends of the premixing swirler are respectively connected with the head of the flame tube and the working fuel nozzle, and the ignition fuel nozzle penetrates through the combustion chamber casing and extends into the flame tube elbow; the premixing swirler comprises a cover plate, a first-stage radial blade, a second-stage radial blade and a horn-shaped evaporation section, the horn-shaped evaporation section is connected with the head of the flame tube, and the horn-shaped evaporation section, the second-stage radial blade, the first-stage radial blade and the cover plate are sequentially connected and are communicated with one another. The backflow combustion chamber disclosed by the invention is used for axially grading fuel oil, so that the ignition and flameout characteristics and the transition state characteristics are ensured, and the emission of pollutants is reduced.

Description

A low-emission recirculation combustor using axially staged combustion

technical field

The invention relates to the technical field of aero-engines, in particular to a low-emission recirculation combustion chamber adopting axially staged combustion.

Background technique

The combustion chamber is one of the core components of aero-engines and ground gas turbines. It is the "heart" of aero-engines and the place where engine pollution emissions are generated. The chemical reaction between aviation kerosene and air in the combustion chamber converts the chemical energy of kerosene into kinetic energy, and a large amount of high-temperature gas expands at the outlet of the combustion chamber to drive the turbine to do work. With the development of the aviation industry in recent years and the environmental pollution at home and abroad Governance and control are becoming more and more stringent, and the pollution emission of aero-engines has also been paid attention to by the industry. How to improve engine performance while reducing engine pollution emissions while taking into account combustion stability, ignition reliability and structural weight and other performances , is the main contradiction that needs to be resolved in the design of the combustion chamber.

At present, the low-pollution design of combustors in domestic aero-engines mainly serves the low-emission combustion organization technology of turbofan engines equipped with large passenger aircraft. The research mainly focuses on key technologies such as the flow field in different partitions of the combustion chamber head, oil-gas mixing, and fuel oil classification. It is necessary to have a large enough space for the height of the flame cylinder cavity in the combustion chamber. Generally, the cavity height is ≥ 80mm, so that there is enough space to realize the complex head. hierarchical structure.

The domestic general aviation industry is developing rapidly. It is an important type of aero-engine for turboshafts for helicopters and turboprops for transport aircraft. It has important applications in national economy and military defense. Larger aircraft are closer to cities, and their pollutant emissions are also highly valued. For the return combustion chamber of small and medium-sized turboshaft/turboprop engines, it is difficult to directly implement the turbofan engine center due to the characteristics of the return combustion chamber flame cylinder cavity height (typically 50mm), large nozzle spacing ratio, and low pressure loss. A graded low-polluting combustion scheme.

Contents of the invention

In view of this, the present invention provides a low-emission recirculation combustor using axially staged combustion, adopting an axially staged combustion organization scheme, and making full use of the long axial length of the recirculation combustion chamber Grading, in the limited backflow combustion chamber space, it not only ensures the characteristics of ignition and transition state, but also realizes the low emission of pollutants.

In order to achieve the above object, the present invention adopts the following technical solutions:

A low-emission recirculation combustor adopting axially staged combustion, comprising: a combustion chamber casing, a flame tube elbow, a flame tube head, an ignition fuel nozzle, a premixing vortex device, and a working fuel nozzle; the flame tube elbow It is fixedly installed in the casing of the combustion chamber, the head of the flame tube is installed at the head end of the elbow of the flame tube, the tail end of the premixing vortex is connected to the head of the flame tube, and the working fuel nozzle Pass through the combustion chamber casing and connect with the head end of the premixing vortex, and the ignition fuel nozzle passes through the combustion chamber casing and extends into the flame tube elbow.

Further, the pre-mixing vortexer includes a cover plate, a first-stage radial vane, a second-stage radial vane and a horn-shaped evaporation section, the tail end of the horn-shaped evaporation section is inserted into the head of the flame tube, and The flame tube elbow is connected, the first-stage radial blades are installed at the head end of the trumpet-shaped evaporation section, the second-stage radial blades are installed on the first-stage radial blades, and the The first-stage radial blades, the second-stage radial blades and the trumpet-shaped evaporating section are connected internally, and the cover plate is installed on the second-stage radial blades.

Further, a plurality of premixed vortexers are annularly distributed on the side wall of the curved tube of the flame tube.

Further, a radial diffuser is also included, and the radial diffuser is installed on the ring-shaped edge of the tail end of the combustion chamber casing.

Further, it also includes a cross-fire nozzle, and the cross-fire nozzle passes through the combustion chamber casing and extends into the flame cylinder elbow.

Further, a plurality of cross-fire nozzles are annularly distributed on the curved pipe of the flame tube.

Further, the pre-mixing swirler further includes a floating mount, which is mounted on the cover plate and connected to the working fuel nozzle.

Further, a plurality of openings are provided on the flame tube elbow.

Further, the trumpet-shaped evaporation section is provided with a plurality of openings.

The beneficial effects of the present invention are:

The present invention adopts the structural scheme of axial classification on the return combustion chamber, fully utilizes the characteristics of the long axial length of the return combustion chamber and the small height of the flame cylinder cavity to carry out fuel classification, and ensures ignition and flameout in the limited space of the return combustion chamber characteristics and transition state characteristics, and realize the low emission of pollutants. And make full use of the relatively low total pressure ratio of the turboshaft engine, and the low risk of spontaneous combustion and flashback brought by lean-burn premixing. The technical route of premixing and pre-evaporation is used to fully exploit the low pollution potential of this technology and suppress its shortcomings.

Description of drawings

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 that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is a structural cross-sectional view of an axially staged combustion low-emission recirculation combustor.

Fig. 2 is a schematic diagram of the circumferential distribution of ignition nozzles and cross-fire nozzles.

Fig. 3 is a schematic diagram of the structure and working principle of the premixing vortexer.

Fig. 4 is a schematic diagram of the structure of the first-stage radial blade of the premixing vortexer.

Among them, in the figure:

1-flame tube elbow, 2-radial diffuser, 3-ignition fuel nozzle, 4-combustion chamber casing, 5-flame tube head, 6-premix vortex, 7-working fuel nozzle, 8- Floating mounting seat, 9-cover plate, 10-first-stage radial blade, 11-second-stage radial blade, 12-horn-shaped evaporation section.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Referring to Figures 1-4, a low-emission recirculation combustor using axially staged combustion includes: a combustor casing 4, a flame tube elbow 1, a flame tube head 5, an ignition fuel nozzle 3, a premixing Vortex 6 and working fuel nozzle 7; the flame tube elbow 1 is located in the combustion chamber casing 4 as a whole, and its tail end is fixedly installed on the combustion chamber casing 4 and communicated with the outside world. The flame tube head 5 is installed in the flame tube At the head end of the elbow 1, the mixture of oil and gas is fully combusted in the space formed by the flame tube elbow 1 and the flame tube head 5; Chamber casing 4 is connected to the head end of premix vortex 6, kerosene is fully mixed with air in premix vortex 6, and then enters into flame tube elbow 1; ignition fuel nozzle 3 extends through combustion chamber casing 4 Into the flame tube elbow 1, the ignition fuel nozzle 3 ignites the oil-air mixture to make it fully combustible. The low-emission recirculation combustor using axially staged combustion also includes a radial diffuser 2, which is installed on the annular edge of the tail end of the combustion chamber casing 4, and the air enters through the radial diffuser 2 The channel between the combustion chamber casing 4 and the flame tube elbow 1, and under the action of the pressure difference between the inside and outside of the flame tube elbow 1, the air enters the head premixing vortex 6 and mixes with the atomized fuel sprayed by the working fuel nozzle 7 , and finally enter the flame tube elbow 1; the low-emission backflow combustor using axially staged combustion also includes a radial diffuser 2, and the cross-fire nozzle passes through the combustion chamber casing 4 and extends into the flame tube elbow 1 , a plurality of cross-fire nozzles are annularly distributed on the flame tube elbow 1, and the ignition fuel nozzle 3 and the cross-fire nozzle jointly ignite the oil-air mixture in the flame tube elbow 1, so that the oil-air mixture can be fully burned.

The premix vortexer 6 includes a cover plate 9, a first-stage radial vane 10, a second-stage radial vane 11, and a horn-shaped evaporation section 12. The tail end of the horn-shaped evaporation section 12 is inserted into the flame tube head 5, and the flame tube The elbow 1 is connected, kerosene and air are fully mixed in the horn-shaped evaporating section 12 and then enter into the flame cylinder elbow 1; The blades 11 are installed on the first-stage radial blades 10, the first-stage radial blades 10, the second-stage radial blades 11 and the trumpet-shaped evaporation section 12 are connected internally, and the cover plate 9 is installed on the second-stage radial blades 11 The air forms swirling air through the first-stage radial blades 10 and the second-stage radial blades 11, the swirling air passing through the two-stage blades is mixed with the atomized fuel sprayed by the working nozzle, and then in the horn-shaped evaporating section 12 Further oil and gas mixing. A plurality of premixing vortexers 6 are annularly distributed on the side wall of the flame tube elbow 1 and can provide sufficient oil-gas mixture to the flame tube elbow 1 . The premix vortex 6 also includes a floating mounting seat 8, the floating mounting seat 8 is installed on the cover plate 9, and is connected with the working fuel nozzle 7, and a plurality of premixing vortex 6 distributed annularly must be connected with the working fuel nozzle 7, The floating mount 8 can facilitate the installation of the working fuel nozzle 7 and the premixing vortex 6. Avoid over-positioning and difficult installation.

A lot of openings are set on the flame tube elbow 1 and the horn-shaped evaporation section 12, which increases the air entry path in the flame tube elbow 1, and the oil-gas mixture passes through the horn-shaped evaporation section 12 at the rear end of the premixing vortex device 6 and is accompanied by The air in the small holes in the evaporation section is further mixed and the oil mist evaporates; the air enters the channel between the combustion chamber casing 4 and the flame tube through the radial diffuser 2, and enters through the opening under the action of the pressure difference between the inside and outside of the flame tube. In the flame tube elbow 1, it helps the oil-air mixture to burn fully.

Example

When working, the air enters the passage between the combustion chamber casing 4 and the flame tube through the radial diffuser 2, and under the action of the pressure difference between the inside and outside of the flame tube elbow 1, the air is premixed from the head of the vortex 6 and the flame tube The opening on the elbow 1 enters the cavity of the flame tube elbow 1, and the air passing through the blades will form swirling air in the first-stage radial blades 10 and the second-stage radial blades 11, and the swirling air passing through the two-stage blades It is mixed with the atomized fuel sprayed by the working nozzle to form an oil-air mixture, and then passes through the horn-shaped evaporation section 12 and is accompanied by the small hole air intake of the horn-shaped evaporation section 12 to further mix fully and evaporate the oil mist, thereby forming a better pollution reduction The effect of emission is that the oil-gas mixture is ignited and combusted in the flame tube elbow 1 through the ignition fuel nozzle 3 and several (usually 4 to 8) co-flame nozzles arranged along the circumferential direction of the flame tube elbow 1. When the inside of the tube 1 is ignited by the flame, high-temperature gas is rapidly formed and discharged from the flame tube bend 1 along the flame tube bend 1.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A low emission reverse flow combustor employing axial staged combustion, comprising: the device comprises a combustion chamber casing, a flame tube bent pipe, a flame tube head, an ignition fuel nozzle, a premixing swirler and a working fuel nozzle; the flame tube elbow is fixedly installed in the combustion chamber casing, the head of the flame tube is installed at the head end of the flame tube elbow, the tail end of the premixing swirler is connected with the head of the flame tube, the working fuel nozzle penetrates through the combustion chamber casing and is connected with the head end of the premixing swirler, and the ignition fuel nozzle penetrates through the combustion chamber casing and extends into the flame tube elbow;

the premixing swirler comprises a cover plate, a first-stage radial blade, a second-stage radial blade and a horn-shaped evaporation section, wherein the tail end of the horn-shaped evaporation section is inserted into the head of the flame tube and is communicated with the bent tube of the flame tube, the first-stage radial blade is installed at the head end of the horn-shaped evaporation section, the second-stage radial blade is installed on the first-stage radial blade, the second-stage radial blade and the horn-shaped evaporation section are communicated with each other internally, and the cover plate is installed on the second-stage radial blade;

the flame tube bent pipe is provided with a plurality of openings;

the horn-shaped evaporation section is provided with a plurality of openings;

air enters a channel between a combustion chamber casing and a flame tube through a radial diffuser, and enters a cavity of the bent tube of the flame tube from openings on a head premixing swirler and the bent tube of the flame tube under the action of the pressure difference between the inside and the outside of the bent tube of the flame tube, the air passing through the blades forms rotational flow air at a first-stage radial blade and a second-stage radial blade, the rotational flow air passing through the two-stage blades is mixed with atomized fuel oil sprayed by a working nozzle to form an oil-gas mixture, and the oil-gas mixture passes through a horn-shaped evaporation section and is further mixed fully along with small holes of the horn-shaped evaporation section, so that oil mist is evaporated.

2. A low emission reverse flow combustor employing axially staged combustion as in claim 1, wherein a plurality of premixed swirlers are annularly distributed on said liner elbow sidewall.

3. The low emission reverse flow combustor according to claim 1, further comprising a radial diffuser mounted to an aft annular rim of the combustor casing.

4. The low emission reverse flow combustor of claim 1, further comprising a cross-flame nozzle extending through the combustor case into the liner elbow.

5. The low emission reverse flow combustor of claim 4, wherein a plurality of said cross-flame nozzles are annularly distributed on said flame tube elbow.

6. The low emission reverse flow combustor of claim 1, wherein said premix swirler further comprises a floating mount mounted to said cover plate and coupled to said working fuel injector.

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