CN107676817B

CN107676817B - Radial multistage swirl nozzle of combustion chamber for burning gaseous fuel

Info

Publication number: CN107676817B
Application number: CN201711143593.7A
Authority: CN
Inventors: 杨谦; 陈明禄; 朱涛; 赵凯岚
Original assignee: China Aero Engine Research Institute
Current assignee: China Aero Engine Research Institute
Priority date: 2017-11-16
Filing date: 2017-11-16
Publication date: 2023-02-28
Anticipated expiration: 2037-11-16
Also published as: CN107676817A

Abstract

The invention provides a radial multistage swirl nozzle of a combustion chamber for combusting gaseous fuel, which comprises a fuel channel, and a central channel, a second-stage channel, a third-stage channel and a fourth-stage channel which are coaxially and sequentially arranged from inside to outside; the fuel passages include a primary fuel passage and a secondary fuel passage; a central channel rotational flow device is arranged in the central channel; a second-stage channel rotational flow device is arranged in the second-stage channel; a third-stage channel rotational flow device is arranged in the third-stage channel; a fourth-stage channel rotational flow device is arranged in the fourth-stage channel; the primary fuel passage corresponds to the central passage; the secondary fuel passage is provided with an inner ring injection port and an outer ring injection port, the inner ring injection port corresponds to the second-stage passage and the third-stage passage, and the outer ring injection port corresponds to the fourth-stage passage.

Description

Radial multistage swirl nozzle of combustion chamber for burning gaseous fuel

Technical Field

The invention belongs to the technical field of nozzles of low-pollution combustion chambers of gas turbines, and particularly relates to a radial multistage swirl nozzle of a combustion chamber for burning gaseous fuel.

Background

With the shortage of energy and the worldwide emphasis on environmental protection, the requirements of various countries on the gas turbine combustor emissions and combustion efficiency become more and more strict, and the gas turbine is generally required to be in a load range of 50% or more, so that the combustor emissions can be maintained at a low level, and the combustion efficiency is kept high.

An important index of the combustion chamber emissions is nitrogen oxide NOx, and the premixed combustion technology is widely used for achieving the purpose of low NOx emissions. Most of the premixing combustors adopt the swirl mixing technology to achieve good mixing of fuel and oxidant, but the combustors working in this state are very easy to generate unstable combustion. To address this problem, engineering has typically adopted a compromise to sacrifice NOx emission performance, namely, using a diffusion flame that is stable but has poor NOx emission performance to stabilize the premixed flame. Generally, the greater the fuel quantity ratio for diffusion combustion, the more stable the combustion, but the greater the NOx emissions. Such a combustion configuration requires that the combustor be carefully designed to handle the conflicting requirements of diffusion flame for NOx emissions and for flame holding capability when designing low pollution combustor nozzles.

In the current energy structure of China, the traditional coal burning technology occupies most of the share. However, the traditional technology has the defects of low efficiency, high pollutant emission (especially NOx emission), high consumption of fresh water resources and the like. The combustion technology using gaseous fuels such as natural gas and the like as fuel is one of clean energy technologies, and can effectively reduce the emission of pollutants while meeting the combustion requirement. Also, the design of the combustor nozzle is particularly important for tissue combustion and pollutant emission reduction.

In the combustion chamber, fuel and air are premixed and changed in speed type through the nozzle, reasonable speed distribution is achieved at the outlet of the nozzle, reasonable fuel and air mixing proportion is matched, and the fuel and the air enter the combustion chamber to be combusted in a organized mode to form a stable flow field and a combustion field. In the prior art, a plurality of combustion paths can be adopted for the design form of the combustion chamber nozzle, and the possibility of independently adjusting the load and the fuel type is given to each combustion path so as to realize a plurality of combustion modes and combinations and realize different load requirements.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a novel radial multistage swirl nozzle of a combustion chamber for burning gaseous fuel, which can reduce pollutant discharge, and has stable flow field and combustion field and easy adjustment. The method is realized through the following technical scheme.

A radial multistage swirl nozzle of a combustion chamber for burning gaseous fuel comprises a fuel channel, and a central channel, a second-stage channel, a third-stage channel and a fourth-stage channel which are coaxially and sequentially arranged from inside to outside; the fuel passages include a primary fuel passage and a secondary fuel passage; a central channel rotational flow device is arranged in the central channel; a second-stage channel rotational flow device is arranged in the second-stage channel; a third-stage channel rotational flow device is arranged in the third-stage channel; a fourth-stage channel rotational flow device is arranged in the fourth-stage channel; the primary fuel passage corresponds to the central passage; the secondary fuel passage is provided with an inner ring injection port and an outer ring injection port, the inner ring injection port corresponds to the second-stage passage and the third-stage passage, and the outer ring injection port corresponds to the fourth-stage passage.

Wherein, the number of the inner ring jet ports can be set to be a plurality, and the number of the outer ring jet ports can also be set to be a plurality.

Further, the gaseous fuel injected from the inner ring injection ports is set to be injected into the third-stage passage alone or to be injected into the second-stage passage and the third-stage passage simultaneously, depending on the fuel flow rate of the secondary-stage fuel passage.

The injection of the gaseous fuel is preferably controlled by the emission momentum ratio. The fuel exit speed is low when the momentum ratio is small, the jet flow track is short, and the fuel completely enters the third-stage channel after being influenced by the transverse airflow; when the momentum ratio is large, the fuel exit speed is high, the jet flow track is long, one part of the fuel enters the third-stage channel, and the other part of the fuel enters the second-stage channel.

Further, the central channel swirling device and the main-stage fuel channel are in annular coaxial staggered configuration.

Further, the central passage swirling device and the main-stage fuel passage are both preferably crescent channel type air passages.

Further, the outer wall surface of the downstream of the central channel is provided with a radial rotation-assisting hole.

The radial rotation-assisting holes can be arranged in a plurality and are uniformly distributed along the circumferential direction of the outer wall surface of the central channel.

Further, the range of the air flow outgoing angle of the radial swirl holes (14) is set to be 0 to 60 degrees between the radial swirl hole air flow outgoing direction and the axial normal direction.

Further, the outlet shape of the central channel is convergent or divergent, the outlet shape of the second-stage channel is convergent or divergent, the outlet shape of the third-stage channel is convergent or divergent, and the outlet shape of the fourth-stage channel is convergent or divergent.

Further, the central passage swirling device includes a hole provided in a passage upstream outer wall surface of the central passage and communicating with the second-stage passage.

Further, the second stage channel swirling device, the third stage channel swirling device and the fourth stage channel swirling device are preferably vane type. The second stage channel rotational flow device, the third stage channel rotational flow device and the fourth stage channel rotational flow device can also be arranged into oblique hole type.

Further, the inner ring injection ports and the outer ring injection ports are arranged offset in the axial direction of the secondary stage fuel passage. The inner ring jet orifice and the outer ring jet orifice are both preferably hole type, and can also be both arranged in an inclined groove type.

Further, the second-stage channel rotational flow device, the third-stage channel rotational flow device and the fourth-stage channel rotational flow device are all set to be axial rotational flow or radial rotational flow; the second-stage channel cyclone device, the third-stage channel cyclone device and the fourth-stage channel cyclone device are preferably clockwise in cyclone direction, and can also be anticlockwise.

The invention has the beneficial effects that:

the technical scheme of the invention can realize a full premix combustion mode. The primary fuel and the air are mixed and emitted in the radial direction and the axial direction, and secondary mixing is carried out by adopting swirl-assisted air radial incidence, so that a fuel-air mixture with high uniformity can be achieved, excellent ignition and flameout performance can be obtained, smoke generation and local hot spot formation under large working conditions are inhibited, and good outlet temperature distribution characteristics are obtained; the secondary fuel is injected inwards and outwards along the radial direction, and the mixing equivalence ratio of the multi-stage cyclone air and the fuel can be flexibly controlled by adjusting the fuel flow, so that the requirements of combustion pollution emission under different working conditions can be met.

Drawings

FIG. 1 is a schematic view of the radial multi-stage swozzle of a gaseous fuel-fired combustor according to an embodiment of the present invention.

FIG. 2 is a three-dimensional cross-sectional view of a central passage structure of a gaseous fuel-fired combustor radial multi-stage swozzle in accordance with an embodiment of the present invention.

FIG. 3 is a front view of a radial multi-stage swozzle of a gaseous fuel-fired combustor according to an embodiment of the present invention.

FIG. 4 is a three-dimensional cross-sectional view of a radial multi-stage swozzle for a gaseous fuel-fired combustor according to an embodiment of the present invention.

Detailed Description

The present invention will be described in detail with reference to the accompanying fig. 1-4, wherein the multi-stage swirl nozzle is a radial swirl nozzle for a gaseous fuel-fired combustor.

As shown in fig. 1-4, the radial multi-stage swirl nozzle of the combustion chamber burning gaseous fuel of the present invention comprises a fuel channel 1, and a central channel 2, a second stage channel 3, a third stage channel 4, and a fourth stage channel 5 which are coaxially and sequentially arranged from inside to outside, wherein the fuel channel 1 comprises a main stage fuel channel 10 and a secondary stage fuel channel 11, the central channel 2 is internally provided with a central channel swirl device 6, the second stage channel 3 is internally provided with a second stage channel swirl device 7, the third stage channel 4 is internally provided with a third stage channel swirl device 8, the fourth stage channel 5 is internally provided with a fourth stage channel swirl device 9, the main stage fuel channel 10 corresponds to the central channel 2, the secondary stage fuel channel 11 is provided with an inner ring jet orifice 12 and an outer ring jet orifice 13, the inner ring jet orifice 12 corresponds to the second stage channel 3 and the third stage channel 4, and the outer ring jet orifice 13 corresponds to the fourth stage channel 5.

Wherein the gaseous fuel injected from the inner ring injection ports 12 is set to be injected into the third-stage passage 4 alone or to be injected into both the second-stage passage 3 and the third-stage passage 4 simultaneously, depending on the fuel flow rate of the secondary fuel passage 11. The injection of the gaseous fuel is controlled by the ejection momentum ratio. The fuel exit speed is low when the momentum ratio is small, the jet flow track is short, and the fuel completely enters the third-stage channel 4 after being influenced by the transverse airflow; when the momentum ratio is large, the fuel exit speed is high, the jet flow track is long, one part of the fuel enters the third-stage channel 4, and the other part of the fuel enters the second-stage channel 3.

As shown in fig. 1, the opposite end of a secondary fuel passage 11 of a radial multi-stage swirler of a combustor burning gaseous fuel with respect to a fuel inlet end (left end in the drawing) extends to an axial middle position of the radial multi-stage swirler, and inner ring injection ports 12 and outer ring injection ports 13 are arranged in a staggered manner. The inner ring injection port 12 is disposed in the axially forward half of the secondary fuel passage 11, and the outer ring injection port 13 is disposed in the axially rearward half of the secondary fuel passage 11. A main stage fuel passage 10 opens in the central passage 2. The secondary fuel passage 11 opens in the wall surface of the tertiary passage 4. The second-stage passage 3 also has a wall surface. The fourth stage channel 5 also has a wall surface. The length of the wall surface of the fourth stage passage 5 in the axial direction is smaller than the length of the wall surface of the third stage passage 4 in the axial direction (but greater than one-half of the length of the wall surface of the third stage passage 4 in the axial direction), and the length of the wall surface of the fourth stage passage 5 in the axial direction is greater than the length of the wall surface of the second stage passage 3 in the axial direction. The outer ring injection ports 13 are provided on the outer wall surface of the third-stage passage 4, and the inner ring injection ports 12 are provided on the inner wall surface of the third-stage passage 4. The inner ring injection ports 12 and the outer ring injection ports 13 are arranged in a staggered manner in the axial direction, each of the inner ring injection ports 12 and the outer ring injection ports 13 is plural, for example, 4, and each of the inner ring injection ports 12 and the outer ring injection ports 13 is uniformly arranged in the circumferential direction of the wall surface of the third passage 4.

As shown in fig. 2, the central passage swirling devices 6 and the main stage fuel passages 10 are arranged in an annular coaxial staggered configuration. The central passage swirling device 6 and the main-stage fuel passage 10 are both crescent channel type air passages. The central passage swirling device 6 includes a hole provided in the passage upstream outer wall surface of the central passage 2 in communication with the second-stage passage 3. The holes of the center passage swirling device 6 are arranged offset from the inner ring injection ports 12 in the axial direction. The outer wall surface of the central passage 2 downstream of the passage is provided with a plurality of radial swirl-assisting holes 14, and the radial swirl-assisting holes 14 are uniformly arranged along the circumferential direction of the wall surface of the central passage 2. The air flow exit angle range of the radial rotation-assisting holes (14) is set to be 0-60 degrees, such as 0 degree, 10 degrees, 20 degrees, 30 degrees, 60 degrees and the like between the radial rotation-assisting hole air flow exit direction and the axial normal direction.

As shown in fig. 3-4, the second stage passage swirling device 7, the third stage passage swirling device 8 and the fourth stage passage swirling device 9 are all vane type. And the rotational flow direction of the second-stage passage rotational flow device 7 is clockwise, the rotational flow direction of the third-stage passage rotational flow device 8 is clockwise, and the rotational flow direction of the fourth-stage passage rotational flow device 9 is counterclockwise. As can be seen from fig. 2 to 3, in the present embodiment, the swirling direction of the central passage swirling device 6 of the central passage 2 is clockwise.

As shown in fig. 4, the downstream channel outlet shape of the central channel 2 is convergent, the downstream channel outlet shape of the second-stage channel 3 is divergent, the downstream channel outlet shape of the third-stage channel 4 is convergent, and the downstream channel outlet shape of the fourth-stage channel 5 is convergent. The overall shape of the radial multistage swirl nozzle for a combustion chamber burning gaseous fuel is cylindrical.

It should be understood that the above-described embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And such obvious variations or modifications which fall within the spirit of the invention are intended to be covered by the scope of the present invention.

Claims

1. A radial multi-stage swirl nozzle of a combustion chamber for combusting gaseous fuel is characterized in that,

the nozzle comprises a fuel channel (1), and a central channel (2), a second-stage channel (3), a third-stage channel (4) and a fourth-stage channel (5) which are coaxially and sequentially arranged from inside to outside;

the fuel passage (1) includes a primary fuel passage (10) and a secondary fuel passage (11);

a central channel rotational flow device (6) is arranged in the central channel (2);

a second-stage channel rotational flow device (7) is arranged in the second-stage channel (3);

a third-stage channel rotational flow device (8) is arranged in the third-stage channel (4);

a fourth-stage channel rotational flow device (9) is arranged in the fourth-stage channel (5);

the primary fuel passage (10) corresponds to the central passage (2);

the secondary fuel passage (11) is provided with an inner ring injection port (12) and an outer ring injection port (13), the inner ring injection port (12) corresponds to the second-stage passage (3) and the third-stage passage (4), and the outer ring injection port (13) corresponds to the fourth-stage passage (5);

the gaseous fuel injected from the inner ring injection ports (12) is set to be injected into the second-stage passage (3) and the third-stage passage (4) simultaneously in accordance with the fuel flow rate of the secondary-stage fuel passage (11);

the central channel swirling device (6) and the main-stage fuel channel (10) are arranged in an annular coaxial staggered manner;

the central channel rotational flow device (6) and the main-stage fuel channel (10) are both crescent channel type air channels;

the outer wall surface of the downstream of the central channel (2) is provided with a radial rotation-assisting hole (14);

the air flow emergent angle range of the radial rotation-assisting holes (14) is set to be 0-60 degrees between the radial rotation-assisting hole air flow emergent direction and the axial normal direction.

2. The gaseous fuel fired combustor radial multi-stage swozzle of claim 1, wherein the channel exit shape of the central channel (2) is convergent or divergent, the channel exit shape of the second stage channel (3) is convergent or divergent, the channel exit shape of the third stage channel (4) is convergent or divergent, and the channel exit shape of the fourth stage channel (5) is convergent or divergent.

3. A gaseous fuel fired combustor radial multi-stage swozzle as claimed in claim 1, wherein said central passage swirler arrangement (6) comprises holes disposed in the passage upstream outer wall surface of said central passage (2) in communication with said second stage passages (3).

4. The gaseous fuel-fired combustor radial multi-stage swozzle of claim 1, wherein the second stage channel swirler means (7), the third stage channel swirler means (8) and the fourth stage channel swirler means (9) are all vane type.

5. The gaseous fuel fired combustor radial multi-stage swozzle of any of claims 1-4, wherein the inner ring injection ports (12) and outer ring injection ports (13) are staggered in an axial direction of the secondary stage fuel passage (11).