JP2004353890A - Fuel injection nozzle for gas turbine engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection nozzle for a gas turbine engine for reducing smoke and soot by preventing the product of a excess fuel region while maintaining the effects of scavenging air on preventing the deposition of carbon. <P>SOLUTION: In the fuel injection nozzle for the gas turbine engine, a fuel injection opening at the front end of the nozzle is opened to a combustor so that liquid fuel is sprayed at a preset injection angle and supplied from the fuel injection opening to the combustor. An enclosure pipe 67 is externally inserted at a gap into the outer periphery at the front end of the nozzle to form a scavenging air outlet as an annular gap in a circular shape concentric with the fuel injection opening. The scavenging air is supplied from the scavenging air outlet to the front end of the nozzle. A turn imparting means 75 is provided in the enclosure pipe 67 for turning the scavenging air supplied from the scavenging air outlet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel injection nozzle for a gas turbine engine equipped with a single-cylinder can type combustor, and more particularly to an improved technique for preventing a decrease in the injection angle of liquid fuel by scavenging air supplied to a nozzle tip.
[0002]
[Prior art]
For example, some gas turbines used in power generation systems have a single-cylinder can-type combustor using liquid fuel. FIG. 6 is a cross-sectional view of a gas turbine engine provided with a single-cylinder can type combustor, FIG. 7 is a front view showing the appearance of a conventional fuel injection nozzle, FIG. 8 is an enlarged view of part A of FIG. 6, and FIG. It is BB sectional drawing of. In this type of gas turbine 1, the air sucked from the intake port 3 is compressed by the rotation of the rotor 7 in the compressor 5, is brought into a high-temperature and high-pressure state, and is guided to the combustor 9. The air guided to the combustor 9 is mixed with the supplied fuel and burned, and becomes high-temperature and high-pressure combustion gas. The combustion gas expands in the turbine section 11, and its energy is converted into the torque of the turbine 13. A part of the rotational force is the power of the compressor 5 and the other part is the output of the gas turbine 1. The combustion gas converted into rotational force by the turbine unit 11 passes through the exhaust unit 15 and is discharged to the outside.
[0003]
The combustor 9 is provided with a fuel injection nozzle 17 for supplying liquid fuel. The fuel injection nozzle 17 has a flange portion 19, as shown in FIG. In the fuel injection nozzle 17, the lower tube 23 is inserted into the combustor 9 by fixing the flange portion 19 to the outer cylinder lid 21 of the combustor 9. A first fuel supply port 25 and a second fuel supply port 27 are opened above the fuel injection nozzle 17, and the liquid fuel supplied from the first fuel supply port 25 flows down a first supply path 29 shown in FIG. To a conical swirl chamber 31. The liquid fuel supplied from the second fuel supply port 27 passes through the second supply path 33 and is supplied from the side surface of the spiral chamber 31. Therefore, the liquid fuel that has merged in the swirl chamber 31 is provided with a swirling component, and is sprayed and supplied at a predetermined injection angle from a fuel injection port 35 opened in the combustor 9. The liquid fuel sprayed and supplied in this manner is atomized by centrifugal force.
[0004]
By the way, since the nozzle tip 37 is cooled by the liquid fuel, the nozzle tip 37 is in a low temperature state, whereby the unburned fuel becomes carbon and easily adheres. For this reason, in the conventional fuel injection nozzle 17, the scavenging air outlet 41, which is a concentric annular gap with the fuel injection port 35, is formed by extrapolating the surrounding pipe 39 with a gap around the nozzle tip 37. By introducing air from the scavenging air inlet 43 shown in FIG. 9 formed in the enclosure pipe 39 and supplying scavenging air from the scavenging air outlet 41 to the nozzle tip 37, carbon deposition was prevented. .
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional fuel injection nozzle, when scavenging air is supplied from the scavenging air outlet, liquid fuel spray-fed at a predetermined injection angle from the fuel injection port interferes with scavenging air supplied from the outside, The injection angle was affected. As a result, the liquid fuel is not sufficiently atomized by the centrifugal force, and an excess fuel region is generated, which is considered to be one of the causes of soot emission.
The present invention has been made in view of the above circumstances, and provides a fuel injection nozzle of a gas turbine engine that can prevent generation of an excess fuel region and reduce soot while maintaining the carbon adhesion preventing effect of scavenging air. It is in.
[0006]
[Means for Solving the Problems]
Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments.
In the fuel injection nozzle 51 according to the first aspect of the present invention, the fuel injection port 35 of the nozzle tip 37 is opened to the combustor 9, and the liquid fuel is injected from the fuel injection port 35 to the combustor 9 at a predetermined injection angle. Along with the spray supply, the scavenging air outlet 41 is formed as an annular gap 83 concentric with the fuel injection port 35 by extrapolating the surrounding pipe 67 with a gap around the outer periphery of the nozzle tip 37, The fuel injection nozzle 51 of the gas turbine engine 1 that supplies scavenging air from the scavenging air outlet 41 to the nozzle tip 37, and a swirl imparting unit 75 that swirls the scavenging air supplied from the scavenging air outlet 41, It is characterized in that it is provided on the surrounding pipe 67.
[0007]
In the fuel injection nozzle 51, in the fuel injection nozzle 51 in which scavenging air is supplied from the scavenging air outlet 41 to the nozzle tip portion 37, the swirling means 75 that swirls the scavenging air supplied from the scavenging air outlet 41 includes an enclosing pipe 67. And the scavenging air supplied from the scavenging air outlet 41 is supplied as a swirling flow contacting the nozzle tip 37 to prevent the carbon from adhering to the nozzle tip 37, and to provide a scavenging air having a swirling component in the radial direction. The outward gas flow is induced, and the injection angle of the liquid fuel is widened. This promotes atomization of the liquid fuel, makes it difficult to generate an excess fuel region, and reduces soot.
[0008]
The fuel injection nozzle 51 according to a second aspect is the fuel injection nozzle 51 of the gas turbine engine according to the first aspect, wherein the swirl providing means 75 is provided on an outer periphery of the enclosure pipe 67 exposed to the air passage 69. At a predetermined angle α with respect to a wall 73 and an imaginary line 81 in the radial direction passing through the center 79 of the surrounding pipe 67, air is perforated in the outer peripheral wall 73 from the ventilation path 69 to the annular gap 83. And a scavenging air introduction port 77 to be introduced.
[0009]
In the fuel injection nozzle 51, positive pressure air is passed through the ventilation path 69, and this air is introduced into the inside of the enclosure pipe 67 from the scavenging air introduction port 77 of the enclosure pipe 67 exposed to the ventilation path 69. A gap that forms an annular space is formed inside the surrounding pipe 67 between the nozzle tip 37 and the annular space. The annular space serves as a scavenging air outlet 41 and surrounds and opens the fuel injection port 35. The air introduced into the surrounding pipe 67 through the scavenging air inlet 77 has a predetermined angle α with respect to the imaginary line 81 in the radial direction, where the scavenging air inlet 41 passes through the center 79 of the surrounding pipe 67. By doing so, it flows down while turning around the axis of the surrounding pipe 67, and is supplied as a swirling scavenging air flow from the scavenging air outlet 41.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a fuel injection nozzle of a gas turbine engine according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view showing the appearance of a fuel injection nozzle according to the present invention, FIG. 2 is a cross-sectional view of a fuel injection nozzle attached to a combustor, and FIG. 3 is a cross-sectional view taken along line AA of FIG. The same members as those shown in FIGS. 6 to 9 are denoted by the same reference numerals and described.
[0011]
The lower part of the main body 53 of the fuel injection nozzle 51 becomes the pipe 23 with the flange 19 as a boundary. The main body 53 has a first fuel supply port 25 and a second fuel supply port 27 opened. As shown in FIG. 2, the tube 23 includes an outer tube 55 and an inner tube 57. The inner tube 57 is mounted inside the outer tube 55 with a gap, and is pressed and fixed via a disc spring 61 by a plug 59 screwed onto the upper surface of the main body 53.
[0012]
The inside of the inner pipe 57 becomes the first supply passage 29 extending in the axial direction, and communicates with the first fuel supply port 25. The gap between the inner pipe 57 and the outer pipe 55 becomes the second supply path 33 and communicates with the second fuel supply port 27. The spiral chamber 31 is fixedly provided at the tip of the outer tube 55. A first supply path 29 is coaxially connected to the spiral chamber 31, and a second supply path 33 is connected to a side surface thereof through a communication hole 63. The tip of the spiral chamber 31 serves as a fuel injection port 35 and is opened to the inner cylinder 65 of the combustor 9.
[0013]
The liquid fuel supplied from the first fuel supply port 25 flows down the first supply path 29 and reaches the conical spiral chamber 31. The liquid fuel supplied from the second fuel supply port 27 passes through the second supply path 33 and is supplied from the side surface of the spiral chamber 31. Therefore, the liquid fuel that has merged in the swirl chamber 31 is provided with a swirling component, and is sprayed and supplied at a predetermined injection angle from a fuel injection port 35 opened in the combustor 9. The liquid fuel sprayed and supplied in this manner is atomized by centrifugal force.
[0014]
An enclosing pipe 67 is inserted at the tip of the outer pipe 55 with a gap. By externally inserting the surrounding pipe 67 with a gap around the outer periphery of the nozzle tip 37, a scavenging air outlet 41 is formed at the tip of the pipe body 23 so as to form a concentric annular gap with the fuel injection port 35. You.
[0015]
The inner cylinder 65 of the combustor 9 is covered by an outer cylinder lid 71 of the combustor 9 via a ventilation path 69. The fuel injection nozzle 51 has the flange portion 19 fixed to the outer cylinder lid 71 and the fuel injection port 35 opened in the inner cylinder 65 of the combustor 9, so that the surrounding pipe 67, which is an intermediate portion thereof, is formed. The outer peripheral wall 73 is exposed to the ventilation path 69. The encircling pipe 67 exposed to the ventilation path 69 is provided with a swirl applying means 75.
[0016]
In the present embodiment, the swirl applying means 75 is constituted by a scavenging air inlet 77 formed in the outer peripheral wall 73. As shown in FIG. 3, the scavenging air introduction port 77 is formed in the outer peripheral wall 73 at a predetermined angle α with respect to an imaginary radial line 81 passing through the center 79 of the surrounding pipe 67. The outer periphery of the distal end of the outer tube 55 is a small-diameter portion 82 having a reduced diameter. The space between the small-diameter portion 82 and the surrounding tube 67 extrapolated to the outer tube 55 forms an annular gap 83. The air in the ventilation path 69 which is at a positive pressure is introduced from the scavenging air introduction port 77 into the annular gap 83. In FIG. 2, reference numeral 85 denotes a swirler (spiral blade).
[0017]
In the fuel injection nozzle 51 configured as described above, for example, positive pressure air (for example, high-temperature high-pressure air or combustion air compressed by the compressor 5) is passed through the ventilation path 69 and is exposed to the ventilation path 69. This air is introduced into the inside of the surrounding tube 67 from the scavenging air introduction port 77 of the surrounding tube 67. A gap (annular gap 83) that forms an annular space is formed between the nozzle tip 37 (small diameter section 81 of the outer pipe 55) inside the enclosing pipe 67, and the annular gap 83 is connected to the scavenging air outlet 41. Thus, the fuel injection port 35 is surrounded and opened. The air introduced into the inside of the surrounding pipe 67 through the scavenging air inlet 77 has a predetermined angle α with respect to the radial virtual line 81 passing through the center 79 of the surrounding pipe 67. As a result, the gas flows down while rotating around the axis of the surrounding pipe 67, and is supplied into the combustor 9 as a swirling scavenging air flow from the scavenging air outlet 41.
[0018]
Therefore, according to the above fuel injection nozzle 51, the scavenging air supplied from the scavenging air outlet 41 is supplied as a swirling flow that comes into contact with the nozzle tip 37, so that carbon adhesion to the nozzle tip 37 is prevented and the swirling air is swirled. The scavenging air of the component induces a gas flow toward the outside in the radial direction, and widens the injection angle of the liquid fuel. This promotes atomization of the liquid fuel, makes it difficult to generate an excess fuel region, and reduces soot. Further, the scavenging air swirled by introducing in the vicinity of the fuel injection port 35, the mixing of the liquid fuel and air is promoted to CO in the exhaust gas, the effect of reducing the NO _x obtained.
[0019]
Figure fuel injection nozzle after measures fabricated in the configuration of the above embodiment, using a fuel injection nozzle before measures conventional configuration to the gas turbine, the exhaust smoke level, the result of comparison NO x _-CO level 4 Shown in FIG.
As is apparent from FIG. 4, it is recognized that the gas turbine using the fuel injection nozzle after the countermeasure reduces the exhaust smoke level at all the load ratios as compared with the gas turbine using the fuel injection nozzle before the countermeasure. Was. Further, as apparent from FIG. 5, in the gas turbine using a fuel injection nozzle after the measures, compared with a gas turbine using a fuel injection nozzle before measures reduced to the NO x _-CO levels in the exhaust gas Was observed.
[0020]
【The invention's effect】
As described above, according to the fuel injection nozzle of the gas turbine engine according to the present invention, the scavenging air supplied from the scavenging air outlet is swirled in the fuel injection nozzle that supplies scavenging air from the scavenging air outlet to the nozzle tip. Since the swirl applying means is provided in the enclosure pipe, scavenging air supplied from the scavenging air outlet can be supplied as a swirling flow contacting the nozzle tip, preventing carbon adhesion to the nozzle tip and having a swirl component. The scavenging air can induce the gas flow toward the outside in the radial direction to widen the injection angle of the liquid fuel. As a result, the atomization of the liquid fuel can be promoted, the generation of an excess fuel region can be prevented, and soot can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view showing the appearance of a fuel injection nozzle according to the present invention.
FIG. 2 is a cross-sectional view of a fuel injection nozzle attached to a combustor.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is an explanatory diagram comparing exhaust smoke levels of a fuel injection nozzle according to the present invention and a conventional nozzle.
FIG. 5 is an explanatory diagram comparing the NO x _-CO levels of the fuel injection nozzle and the conventional nozzle in accordance with the present invention.
FIG. 6 is a sectional view of a gas turbine engine provided with a single-cylinder can combustor.
FIG. 7 is a front view showing the appearance of a conventional fuel injection nozzle.
FIG. 8 is an enlarged view of a part A of FIG. 6;
FIG. 9 is a sectional view taken along line BB of FIG. 8;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Gas turbine engine 9 ... Combustor 35 ... Fuel injection port 37 ... Nozzle tip 41 ... Scavenging air outlet 51 ... Fuel injection nozzle 67 ... Enclosure pipe 69 ... Ventilation path 83 ... Annular gap 73 ... Outer peripheral wall 75 ... Turning Means 77: scavenging air introduction port 79: center 81 of the enclosure tube: virtual imaginary line α in the radial direction: predetermined angle

Claims (2)

A fuel injection port at a nozzle tip is opened to a combustor, and liquid fuel is sprayed and supplied from the fuel injection port to the combustor at a predetermined injection angle, and an enclosing pipe having a gap at an outer periphery of the nozzle tip. Is a fuel injection nozzle of a gas turbine engine, which forms a scavenging air outlet which is a concentric annular gap with the fuel injection port by supplying the scavenging air from the scavenging air outlet to the nozzle tip. hand,
A fuel injection nozzle for a gas turbine engine, wherein a swirl applying means for swirling scavenging air supplied from the scavenging air outlet is provided in the enclosure pipe. The fuel injection nozzle for a gas turbine engine according to claim 1, wherein
The turning imparting means,
An outer peripheral wall of the enclosing pipe exposed to the air ventilation path,
A scavenging air inlet that is bored in the outer peripheral wall at a predetermined angle with respect to an imaginary line in the radial direction passing through the center of the enclosure pipe and that introduces air from the ventilation path into the annular gap. A fuel injection nozzle for a gas turbine engine.

Images