KR101971596B1 - A combustor reducing nitrogen oxide improving main nozzle - Google Patents

Abstract

The present invention is characterized in that a plurality of small fuel lean / fuel rich flames are formed on the entire combustor end surface by a plurality of fuel nozzles formed at the center of the fuel nozzle, The present invention relates to a combustor that minimizes nitrogen oxides (NOx) that improves the main nozzles. A simple configuration can realize a basic combustion system without the need for a peripheral device, and a heat dissipation through a small split flame, It is possible to remarkably reduce nitrogen oxides (NOx) through the formation of optimized air-fuel ratio flames and induction of fast combustion reaction of each small flame.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a low-NOx burner having improved main nozzles,

The present invention relates to a low NOx combustor, and more particularly to a low NOx combustor in which a plurality of small fuel lean / fuel rich flames are formed by a plurality of fully separated fuel nozzles, To a combustor which is formed over the entire cross-section of the end of the combustor to minimize nitrogen oxides (NOx) which are improved in the main nozzles generated in the flame.

A combustor for reducing nitrogen oxides is a system that suppresses the generation of nitrogen oxides generated in the combustion process by various methods such as controlling the mixing characteristics of the fuel and the air, or adjusting the oxygen concentration and the flame temperature in the combustion region.

Through this process, the optimized combustor can cope with various regulations on air pollutants due to current environmental problems and it is applied to almost all industries that generate energy by using combustion system.

Currently, domestic and foreign N2OX is limited to entering the market when it is not a low NOx combustor in terms of emission concentration regulation, total amount regulation, conversion to fine dust. In addition, lower NOx regulations are anticipated, and low NOx performance has the greatest effect on market share.

In order to reduce nitrogen oxide, which is an environmental pollutant, combustion techniques that are currently generally applied include technologies such as fuel and air multi-stage technology, exhaust gas recirculation technology, combustion gas internal recirculation technology, reheat combustion, OFA and the like. However, these combustion techniques require additional external devices and require a complicated structure of peripheral devices. Therefore, in order to overcome the disadvantages of the above-described techniques, research and development for integrating and optimizing various combustion techniques have been widely carried out both domestically and internationally.

On the other hand, there has not been disclosed a combustor in which a plurality of small fuel lean / fuel rich flames are formed on the entire end face of the combustor by a plurality of fuel nozzles formed with fuel nozzles at the center and completely separated from each other.

Korean Patent Registration No. 10-096857 discloses a fuel injection module including a primary fuel injector and two or more secondary fuel injectors disposed around the primary fuel injector. An air injection module for supplying an oxidant to the fuel injection module; And a fuel supply module for supplying fuel to the fuel injection module, wherein the secondary fuel injection body is radially disposed on a circumference around the primary fuel injection body, Wherein a primary space is formed and a secondary space is formed from the secondary fuel injection body spaced apart from the primary space to form a multistage flame. However, it can not be confirmed that a fuel nozzle is formed at the center and a plurality of fuel lean / fuel rich flames are formed.

Korean Patent Registration No. 10-1512352 discloses a fuel injection system comprising a primary fuel injector for injecting a main fuel into a combustion furnace, at least one or more fuel injectors arranged around the primary fuel injector, A recirculating induction portion for recirculating the combustion gas generated in the combustion furnace to the combustion furnace by a hydrodynamic force, a fuel supply portion for supplying fuel to the primary fuel injector and the secondary fuel injector, An oxidant supplier for supplying an oxidant to a space between the primary fuel injector and the secondary fuel injector, and an air multi-stage sleeve arranged to surround the primary fuel injector for the air multi-stage, Wherein the oxidant supplied from the supply unit is supplied in multiple stages through the inner and outer portions of the air multi-stage sleeve. It has set forth. However, it can not be confirmed that a fuel nozzle is formed at the center and a plurality of fuel lean / fuel rich flames are formed.

Thus, a plurality of small-sized fuel lean / fuel rich flames are formed on the entire end face of the combustor by a plurality of fuel nozzles formed with a main fuel nozzle at the center and completely separated from each other, No combustion technology has been proposed to minimize NOx.

(Patent Document 0001) Korean Patent Registration No. 10-096857

(Patent Document 0002) Korean Patent Registration No. 10-1512352

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks of the inventors of the present invention by carrying out in-depth research and various experiments. The object of the present invention is to provide a fuel- lean / fuel rich flame is formed in the entire end face of the combustor, and the total flame has an excess air ratio of between 1.0 and 1.2, which is optimized on the average energy efficiency, so that the combustion is carried out at an optimized excess air ratio at a low flame temperature .

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems occurring in the prior art,

housing; A fuel supply unit installed in the housing and having a plurality of fuel flow paths having fuel nozzles coupled to one end thereof; An air injecting portion having a plurality of air holes formed by the fuel nozzle being drawn in; A fuel control unit for controlling fuel injected into the fuel passage; And a main fuel nozzle coupled to the fuel flow path and formed at a center axis of an end of the air injection part formed in the housing, wherein the main fuel nozzle includes a main fuel nozzle and an air control part for controlling air to be injected into the housing. Characterized by a nitrogen oxide combustor.

In an embodiment of the present invention, D _OF / D _{IA, which} is the ratio of the outer diameter (D _OF ) of the fuel nozzle to the inner diameter (D _IA ) of the air hole, may be 0.99 to 0.01.

In an embodiment of the present invention, the outer diameter (D _OF ) of the fuel nozzle may be the same.

In an embodiment of the present invention, the D _OF / D _{OMF, which} is the ratio of the outer diameter (D _OF ) of the fuel nozzle to the outer diameter (D _OMF ) of the main fuel nozzle may be 1 to 0.01.

In an embodiment of the present invention, the tip end (L _MF ) of the main fuel nozzle may be positioned 0.1 to 20 times the outer diameter (D _OMF ) of the main fuel nozzle with respect to the end of the air injecting portion.

In an embodiment of the present invention, the tip (L _F ) of the fuel nozzle may be 0.1 to 20 times the outer diameter (D _OF ) of the fuel nozzle with respect to the end of the air injector.

In an embodiment of the present invention, one or more than two fuel injection holes may be formed in the nozzle tip of the fuel nozzle.

In the embodiment of the present invention, the fuel injection hole may be formed in any one of a coaxial direction, a tangential direction, an oblique direction, a clockwise direction, and a counterclockwise direction.

In an embodiment of the present invention, an air hole having a pivot block may be formed around the fuel nozzle and / or the main fuel nozzle.

In the embodiment of the present invention, the main fuel nozzle is formed at the outer cylinder center portion formed by the air holes, and the main fuel injection port formed at the rear end of the main fuel nozzle, .

As described above, the effect of the present invention with the above-described configuration is that a basic combustion system can be implemented without a peripheral device as a simple constitution.

In addition, there is an effect that nitrogen oxides (NOx) can be remarkably reduced through heat dispersion through a small split flame, decrease in flame temperature, formation of an optimized air-fuel ratio of each small flame, and induction of a fast combustion reaction.

Further, there is an effect that control of the combustion condition according to the amount of load through the main fuel nozzle is facilitated.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

Figure 1 is a graph of the correlation between nitrogen oxide and excess air ratio.
2 is a perspective view of a low nitrogen oxide combustor in accordance with an embodiment of the present invention.
3 is a cross-sectional view of a low nitrogen oxide combustor in accordance with an embodiment of the present invention.
4 is a cross-sectional view of an air injecting unit and a fuel nozzle according to an embodiment of the present invention.
5 is an operational state diagram of a low nitrogen oxide combustor according to an embodiment of the present invention.
6 is a cross-sectional view of a low NOx combustor in accordance with an embodiment of the present invention and an enlarged view of a burned-in air nozzle.
7 is a view of a fuel nozzle according to an embodiment of the present invention.
8 is a view of a main fuel nozzle according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, it includes not only a case where it is directly connected but also a case where the other part is indirectly connected with another part in between. In addition, the inclusion of an element does not exclude other elements, but may include other elements, unless specifically stated otherwise.

The present invention will be described in detail with reference to the drawings.

FIG. 2 is a perspective view of a low-nitrogen oxide combustor according to an embodiment of the present invention, and FIG. 3 is a graph showing the relationship between the nitrogen oxide and the excess air ratio in the low- Fig.

As shown in FIGS. 2 and 3, the low nitrogen oxide combustor of the present invention includes a housing 300; A fuel supply unit 100 installed in the housing 300 and having a plurality of fuel flow paths 110 to which fuel nozzles 120 are coupled at one end; An air injector (200) having a plurality of air holes (210) through which the fuel nozzle (120) is drawn and passed; A fuel control unit 510 for controlling the fuel injected into each of the fuel flow paths 110; And an air control unit 520 for controlling the air to be introduced into the housing 300. The air control unit 520 is coupled to the fuel passage 110 to control the center axis of the air injection unit 200 formed at the housing 330, And a main fuel nozzle 130 formed in the main fuel nozzle 130.

That is, the inner peripheral size of one of the air holes and the inner peripheral size of the other of the air holes may be different from each other.

The one fuel nozzle 120 and the one air hole 210 may be formed as a pair. The ratio of the fuel injected into the fuel nozzle and the air injected from the air hole may be an excess air ratio of between 1.0 and 1.2.

A small flame 400 is formed by a pair of the fuel nozzle 120 and the air hole 210. Further, a main flame is formed by the main fuel nozzle to generate a heat amount required by the boiler.

The main flame and the whole flames by a plurality of small flames have an excess air ratio of between 1.0 and 1.2, which energy efficiency is optimized on average as shown in Fig. 1, so that combustion is performed at an optimized excess air ratio at a low flame temperature .

That is, in the low nitrogen oxide combustor according to the present invention, the main flame and the plurality of small flames 400 can perform combustion at an optimum air-fuel ratio even at a low temperature, thereby remarkably reducing the nitrogen oxide produced during combustion.

The number of fuel dispersions is the same as the number of the main fuel nozzles 130 and the fuel nozzles 120, and the number of the fuel nozzles 120 may vary depending on application conditions such as heat input amount, fuel type, and the like.

The main fuel nozzle is formed in the outer cylinder center portion formed by the air hole, the main fuel injection hole 134 formed at the rear end of the main fuel nozzle, and the small portion of the main fuel injection hole may be formed with the throttling portion 131 .

An inner main fuel nozzle 132 and an inner air nozzle 133 may be formed at an inlet side of the throttle portion and an air inlet 135 may be formed at a side of the main fuel injection port.

The housing 300 can perform the function of a wind box.

In the embodiment of the present invention, it is described that the air introduction by the air control unit 520 is performed on the side surface of the housing 300, but the present invention is not limited thereto and the air introduction direction may be changed.

FIG. 4 is a cross-sectional view of an air injector 200 and a fuel nozzle 120 according to an embodiment of the present invention, and FIG. 5 is a view illustrating an operation of a low nitrogen oxide combustor according to an embodiment of the present invention. 5 is an operational state diagram for a front view of a low NOx combustor, and the right side view of FIG. 5 is an operational state diagram for a cross section of a low NOx combustion engine.

3 and 4, the fuel nozzle 120 may penetrate the air hole 210 while being spaced apart from the inner periphery of the air hole 210 by a predetermined distance so as to form the air passage 211 . Further, the main fuel nozzle 130 may be formed at the center.

Here, the air passage 211 may be the remaining space of the air hole 210 except for the space occupied by the fuel nozzle 120. In the air hole 210, air can be passed through the air passage 211 and injected in the direction of the combustion chamber.

(The combustion chamber is not shown but may mean a space where the entire flame is formed.)

As described above, when the sizes of the inner peripheries of the air holes 210 are different, the sizes of the air passages 211 may be different from each other.

The diameter of the fuel flow path 110 may be the same as the diameter of the air flow path 211.

4, the small flame 400 formed by the pair of the fuel nozzles 120 and the air and the air injected from the air holes 210 is divided into a fuel rich flame 410 having a low air- And a fuel lean flame 420 having a high air-fuel ratio. Further, the main flame formed by the fuel injected from the main fuel nozzle and the air injected from the air holes arranged in an annular shape can be formed in the center portion.

That is, due to the difference in air injection quantity depending on the size of the air flow passage 211, the small flame 400 is rich in fuel so that the fuel becomes rich (fuel rich) at a low air-fuel ratio compared with the fuel nozzle 120 that injects the same amount of fuel, The flame 410 and the fuel lean can be divided into the fuel lean flame 420 having a high air-fuel ratio.

D _OF / D _{IA, which} is the ratio of the outer diameter (D _OF ) of the fuel nozzle 120 to the inner diameter (D _IA ) of the air hole 210, may be 0.99 to 0.01.

D _OF / D _{IA, which} is the ratio of the outer diameter (D _OF ) of the fuel nozzle to the inner diameter (D _IA ) of the air hole, may be 0.99 to 0.01.

If the ratio of the outer diameter (D _OF ) of the fuel nozzle to the inner diameter (D _IA ) of the air hole deviates, a smooth combustion condition may not be formed or a large amount of nitrogen oxides may be generated.

The outer diameter (D _OF ) of the fuel nozzle may be the same. The combustion condition can be controlled by adjusting the inner diameter of the air hole while keeping the outer diameter of the plurality of fuel nozzles corresponding to the fuel supply unit having the plurality of fuel flow paths constant.

When the fuel supplied under the thermal load condition of 80,000 kcal / hr based on the heat load is limited to LNG, the linear velocity of supplied air may be 10 to 50 m / sec. Preferably 30 to 40 m / sec.

If the above conditions are exceeded, a smooth combustion condition is not formed or nitrogen oxide suppression suitable for a load condition can not be achieved.

When a plurality of fuel rich flames 410 and a plurality of fuel lean flames 420 are formed to form an entire flame, as shown in FIG. 1, the entire flame has an excess air ratio of 1.0 to 1.2 And the temperature of the entire flame is also lowered, so that the nitrogen oxide can be reduced.

Two or more air holes 210 whose inner circumferential sizes are different from each other may be alternately arranged.

Accordingly, the fuel rich flame 410 and the fuel lean flame 420 can be alternately arranged.

In the arrangement of the small flames 400, when the fuel rich flames 410 are concentrated in one direction and the fuel leash flames 420 are concentrated in the other direction, The flame may not be uniform.

In addition, the entire flame can be uniformed or the calorific value required of the boiler can be controlled through the main flame formed from the fuel dispersed from the main fuel nozzle.

If the entire flame is not uniform, the combustion efficiency may be lowered, so that the fuel rich flame 410 and the fuel lean flame 420 may be alternately arranged and installed to obtain a uniformly formed flame.

The air holes 210 may be arranged in an annular shape. Specifically, a plurality of arbitrary air holes 210 may be concentrically arranged from the center of the air injection portion 200.

Here, a plurality of air holes 210 having the same inner circumferential diameter may be continuously arranged along one circumference on one concentric circle. Or a plurality of air holes 210 having different inner circumferential diameters may be successively disposed along one circumference on one concentric circle.

The fuel rich flame 410 and the fuel lean flame 420 may be arranged in an annular shape.

The small flame 400 formed by the fuel nozzle 120 and the air hole 210 may be preferably arranged annularly to form a uniformly uniform whole flame.

However, the present invention is not limited to this, and it is also possible to arrange them in a hexagonal shape and a polygonal shape by external factors such as the use of the combustor and the installation position.

The air injection portion 200 may be replaceable.

The air-fuel ratio of the fuel rich flame 410 or the fuel lean flame 420 may vary depending on the use of the combustor, the installation environment of the combustor, the installation type of the combustor, and the like.

Accordingly, in order to vary the air-fuel ratio of the fuel rich flame 410 or the fuel lean flame 420, the diameter of each air hole 210 is different from that of the air injector 200 before the replacement, The air injection unit 200 can be replaced.

When the air nozzles 210 are exchanged for different air injectors 200 with different diameters, the respective air passages 211 are different, and the air supply amount to each fuel nozzle 120 is changed, The air-fuel ratio of the small flame 400 may be varied.

The air hole 210 may have a swivel for counterboring.

The swirler can be installed at a portion where air is introduced into the air hole 210. Alternatively, the swirler may be formed on the inner surface of the air hole 210 forming the air passage 211.

Although the air hole 210 is circular in the embodiment of the present invention, the air hole 210 is not limited to the circular shape, but may be formed in an elliptic or polygonal shape.

In the embodiment of the present invention, in order to differentiate the air-fuel ratio of the small flames 400 with a simple structure, the diameter of the air holes 210 forming a pair with the fuel nozzles 120 for injecting the same amount of fuel, So that the air-fuel ratio is different.

However, the present invention is not limited thereto, and each of the fuel nozzles 120 can inject fuel by differentiating the fuel concentration.

To this end, the fuel control unit 510 may supply different amounts of fuel to the respective fuel flow paths 110 to form the small flames 400 having different air-fuel ratios.

Although the small flame 400 is divided into the fuel rich flame 410 and the fuel lean flame 420 in the embodiment of the present invention, the plurality of fuel rich flames 410 also have different air-fuel ratios, The fuel lean flame 420 may also have different air-fuel ratios.

5, the tip end L _MF of the main fuel nozzle may be 0.1 to 20 times the outer diameter (D _OMF ) of the main fuel nozzle with respect to the end of the air injection part.

The tip (L _F ) of the fuel nozzle may be 0.1 to 20 times the outer diameter (D _OF ) of the fuel nozzle with respect to the end of the air injecting portion.

6 is a cross-sectional view of a low NOx combustor according to an embodiment of the present invention and an enlarged view of a combustion-completed air injection port 310. FIG.

5, the low nitrogen oxide combustor of the present invention is a gap between the inner surface of the housing 300 and the outer portion of the air injecting portion 200, and the combustion complete air (overfire air) 311) is injected into the combustion chamber.

The laminating flow unit 320 may be provided at the end of the housing 300 in the direction of spraying the combustion completion air 311 and may provide a curved flow path to the combustion completion air 311.

The laminar flow section 320 includes a curved member 321 for guiding the combustion completion air 311 discharged along the periphery of the housing 300 to be discharged toward the center of the combustion chamber, Shaped member 322 that provides a vortical flow to the combustion-completed air 311 that is coupled and discharged along the circumference of the end of the combustion zone 311.

The combustion completion air 311 supplied from the combustion completion air injection port 310 acts as an oxidant for the entire flame and proceeds to a path near the outer surface of the entire flame, that is, the inner surface of the combustion chamber, It flows in the form of wrapping the whole flame and can function to oxidize unburned hydrocarbons or carbon monoxide which may occur at the end of the entire flame.

2 and 5, when the housing 300 is formed in a cylindrical shape, a combustion-completed air injection opening 310 is formed in a ring shape around the outer periphery of the circular air injection portion 200 .

The ring-shaped member 321 having a curved inner surface may be coupled to the end of the housing 300 in the form of a ring so that the ring-shaped member 322 having a circular cross section may be provided so as to be formed by cutting a part of the tube .

Here, the space between the outer surface of the ring-shaped member 322 and the inner surface of the curved member 321 can provide a curved flow path to the combustion completion air 311. [

The radius of curvature of the inner surface of the curved member 321 and the radius of curvature of the ring member 322 may be different.

The laminar flow portion 320 may be formed by the curved member 321, the ring-shaped member 322, and the curved flow path.

The combustion-completed air 311 that has passed through the laminar flow section 320 is increased in fluidity in the straight direction by the laminar flow, and the oxidizer function as described above can be efficiently performed.

When the radius of curvature of the inner surface of the curved member 321 or the radius of curvature of the end surface of the ring-shaped member 322 is adjusted to change the size of the curved flow path, the flow rate or flow rate of the combustion completion air 311 can be adjusted.

It goes without saying that the ring-shaped member 322 can be replaced for the purpose of adjusting the flow rate or the flow rate of the combustion completion air 311.

The low nitrogen oxide combustor of the present invention may further include an exhaust gas hole or an exhaust gas slit for exhaust gas recirculation in the combustion chamber. (Exhaust gas holes or exhaust gas slits are not shown.)

An exhaust gas hole or an exhaust gas slit may be provided on the side surface of the housing 300.

The exhaust gas in the closed combustion chamber can be recirculated through the exhaust gas hole or the exhaust gas slit by being injected from the high-pressure combustion chamber into the relatively low-pressure housing 300, mixed with air and injected.

Although the exhaust gas holes or the exhaust gas slits are provided on the side surface of the housing 300 in the embodiment of the present invention, the exhaust gas holes or the exhaust gas slits are not necessarily provided, And may be mixed with the supplied air and supplied.

7 illustrates the shape of a nozzle according to an embodiment of the present invention.

One or two or more fuel injection holes 121 may be formed in the nozzle tip of the fuel nozzle 120.

The fuel injection port may be formed in any one of a coaxial direction (a), a tangential direction (b), an oblique direction (c), a clockwise direction (d), and a counterclockwise direction (e).

FIG. 8 shows a shape of a main nozzle according to an embodiment of the present invention.

An air hole may be formed around the fuel nozzle and / or the main fuel nozzle.

The main fuel nozzle is formed at the outer cylinder center portion formed by the air holes, and the main fuel injection port formed at the rear end of the main fuel nozzle, the minor portion of the main fuel injection port may be formed with a throttle portion.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

1: Boiler
2: Economizer
3: First pressurized blower
4: air supply path
5: Exhaust gas circulation passage
6: first air damper for combustion
7: second air damper for combustion
8: Third air damper for combustion
9: Second pressurized blower
10: Exhaust gas damper
11: heating medium tube
12: Flue gas recirculation part
13: Heat exchanger
100: fuel supply unit
110: fuel flow path
120: Fuel nozzle
130: main fuel nozzle
200:
210: air hole
211: air flow
300: housing
310: Combustion completed air nozzle
311: Combustion complete air
320: laminar flow
321: Curved member
322: ring member
400: Small flame
410: fuel rich flame
420: Fuel Lean Flame
510: fuel control unit
520:

Claims (10)

housing;
A fuel supply unit installed in the housing and having a plurality of fuel flow paths having fuel nozzles coupled to one end thereof;
An air injecting portion having a plurality of air holes formed by the fuel nozzle being drawn in;
A fuel control unit for controlling fuel injected into the fuel passage; And
An air control unit for controlling air introduced into the housing;
Lt; / RTI >
And a main fuel nozzle coupled to the fuel flow path and formed at a central axis of an end of the air injection part formed in the housing,
Further comprising a combustion-completed air ejecting opening through which combustion-completed air is ejected as a gap between an inner surface of the housing and an outer periphery of the air ejecting portion,
Further comprising a laminar flow section provided at an end of the housing in the combustion-completed air injection direction and providing a curved flow path to the combustion-completed air,
Wherein the laminar flow portion includes a curved member for guiding the combustion completion air discharged along the periphery of the housing to be discharged toward the center of the combustion chamber, And a ring-shaped member for providing a vortex flow in the combustion chamber.
The method according to claim 1,
Wherein the ratio D _OF / D _IA of the outer diameter (D _OF ) of the fuel nozzle to the inner diameter (D _IA ) of the air hole is 0.99 to 0.01.
The method of claim 2,
And the outer diameter (D _OF ) of the fuel nozzle is the same.
The method of claim 2,
_{Wherein the} ratio D _OF / D _OMF of the outer diameter (D _OF ) of the fuel nozzle to the outer diameter (D _OMF ) of the main fuel nozzle is 1 to 0.01.
The method of claim 4,
Wherein a tip end (L _MF ) of the main fuel nozzle is positioned 0.1 to 20 times the outer diameter (D _OMF ) of the main fuel nozzle with respect to the end of the air injection part.
The method of claim 2,
Wherein the tip end (L _F ) of the fuel nozzle is positioned 0.1 to 20 times the outer diameter (D _OF ) of the fuel nozzle with respect to the end of the air injection portion.
The method according to claim 1,
Wherein one or more fuel injection holes are formed in the nozzle tip of the fuel nozzle.
The method of claim 7,
Wherein the fuel injection hole is formed in any one of a coaxial direction, a tangential direction, an oblique direction, a clockwise direction, and a counterclockwise direction.
The method according to claim 1,
Wherein an air hole having a pivot block is formed around the fuel nozzle and / or the main fuel nozzle.
The method according to claim 1,
Wherein the main fuel nozzle is formed at an outer cylinder center portion formed by the air hole and the main fuel injection port is formed at a rear end of the main fuel nozzle, .

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