JP2003014233A - Fuel injection nozzle for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve ignition property and low fuel cost property in a fuel injection nozzle for gas turbine by promoting the atomization of a fuel. SOLUTION: A fuel injection nozzle for gas turbine has first air nozzle cylinder 10 disposed at the center thereof and a fuel nozzle cylinder 11, a secondary air nozzle cylinder 12, and a third air nozzle cylinder 13 disposed in order coaxially on an outer periphery of the cylinder. An inner surface of an injection hole 11a of the fuel nozzle cylinder 11 is formed into a cylindrical rectifying surface 21 such that a fuel injected from the injection hole 11a is formed into a cylindrical film. Further an injection hole 10c of the first air nozzle cylinder 10 is formed such that an air stream from the injection hole 10c collides against the foregoing cylindrical film shaped film injected from the injection hole 11a of the fuel nozzle cylinder 11. A twisting direction of swirler means 29a in the fuel nozzle cylinder 11 is set oppositely to that of swirler means 17 in the first air nozzle cylinder 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection nozzle for a gas turbine, and more particularly, a first air nozzle cylinder is arranged at a central portion, and a fuel nozzle cylinder, a second air nozzle cylinder and a third air nozzle are provided on the outer periphery thereof. The cylinders are sequentially arranged concentrically, and
The nozzle holes of the first air nozzle cylinder, the fuel nozzle cylinder, the second air nozzle cylinder, and the third air nozzle cylinder that open to the combustion chamber are offset in that order along the axial direction toward the combustion chamber side, A fuel manifold is connected to the inlet, the inlets of the first to third air nozzle cylinders are opened to the compressed air chamber, and a swirler means for imparting a swirling flow to the fuel or air passing through each fuel and air nozzle cylinder And a tapered narrowed portion located immediately before each injection hole.

[0002]

BACKGROUND OF THE INVENTION Fuel injection nozzles for such gas turbines are already known, for example as disclosed in US Pat. No. 5,417,054.

[0003]

In the gas turbine, it is extremely important to atomize the fuel ejected from the fuel injection nozzle in order to improve the ignitability and the fuel economy. Further, stabilizing the fuel spray pattern in an optimum conical shape for a desired combustion method or combustion chamber shape is important for ensuring ignitability, flame holding property, and low emission property.

In view of the above points, the present invention aims to improve the ignitability, the fuel economy and the flame retention by atomizing the fuel and stabilizing the conical spray pattern. A fuel injection nozzle for a vehicle is provided.

[0005]

In order to achieve the above-mentioned object, the present invention has a first air nozzle cylinder arranged at the center,
A fuel nozzle cylinder, a second air nozzle cylinder, and a third air nozzle cylinder are sequentially arranged concentrically on the outer periphery thereof, and a first air nozzle cylinder, a fuel nozzle cylinder, a second air nozzle cylinder, and a third air nozzle cylinder that open to the combustion chamber The injection holes of the air nozzle cylinder are offset in that order toward the combustion chamber along the axial direction, the fuel manifold is connected to the inlet of the fuel nozzle cylinder, and the inlets of the first to third air nozzle cylinders are compressed air chambers. For gas turbines, each of the fuel and air nozzle cylinders is provided with swirler means for imparting a swirl flow to the fuel or air passing therethrough and a tapered narrowing portion located immediately before each injection hole. In the fuel injection nozzle, the inner surface of the injection hole of the fuel nozzle cylinder is formed as a cylindrical straightening surface for forming the fuel ejected from the injection hole into a cylindrical film shape.
The nozzle hole of the air nozzle cylinder is formed so that the air flow from the nozzle hole collides with the cylindrical film-like fuel ejected from the nozzle hole of the fuel nozzle cylinder, and the twisting direction of the swirler means in the fuel nozzle cylinder is formed. The first feature is that the twisting direction of the swirler means in the first air nozzle cylinder is set to be opposite to each other.

According to the first feature, in the fuel nozzle cylinder, while the fuel passing therethrough is swirled by the swirler means, it is rectified into a cylindrical film-like flow by the rectification surface of the injection hole. On the other hand, the first air nozzle cylinder swirls the high-pressure air flowing from the compressed air chamber by the swirler means to straighten it by the straightening surface of the nozzle hole and directs it toward the nozzle hole of the fuel nozzle cylinder. Of the cylindrical film-like fuel ejected from the fuel nozzle cylinder is opposite to the swirling direction, the fuel ejected from the fuel nozzle cylinder and the air ejected from the injection hole of the first air nozzle cylinder violently collide with each other. Thus, atomization of fuel and mixing of fuel and air can be effectively performed. The second
The atomization of the fuel can be further promoted by the air ejected from the air nozzle cylinder, and the ignitability and the fuel economy can be improved.

In addition to the first feature, the present invention has a second feature.
The twisting direction of the swirler means in the air nozzle cylinder and the twisting direction of the swirler means of the third air nozzle cylinder are set to be the same direction, and the twisting angle of the swirler means of the second air nozzle cylinder is set to be larger than the twisting angle of the swirler means. The second characteristic is that the twist angle of the swirler means is set large and the taper angle of the narrowing portion of the third air nozzle cylinder is set to be larger than the taper angle of the narrowing portion of the second air nozzle cylinder. To do.

According to the second feature, it is possible to promote the mixing of the outer peripheral portion of the spray pattern of the air-fuel mixture mainly by the air ejected from the third air nozzle cylinder, and to improve the ignitability and the flame holding property. it can.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a main part of a gas turbine equipped with a fuel injection nozzle of the present invention, FIG. 2 is an enlarged vertical sectional view of the fuel injection nozzle, and FIG. 3 is a first air nozzle cylinder of the fuel injection nozzle. A side view and FIG. 4 are sectional views taken along line 3-3 of FIG.

First, in FIG. 1, a compressed air chamber 2 is formed in an engine case 1 of a gas turbine and communicates with an outlet of a compressor (not shown), and an annular combustion chamber 3 is arranged in the compressed air chamber 2. It This combustion chamber 3
Is composed of a cylindrical inner casing 4 and a cylindrical outer casing 5 surrounding the inner casing 4. One end of the outer casing 5 has an annular end wall connected to one end of the inner casing 4. 5a are integrally connected. A plurality of fuel injection nozzles N arranged in an annular shape are attached to the end wall 5a via nozzle supporting means 6, respectively. The nozzle supporting means 6 is provided with the end wall 5
The support base 7 has a funnel-shaped support base whose inner end is fixed to a, and a holding ring 8 attached to a flange portion 7a formed on the outer end of the support base 7. The holding ring 8 has a holding ring. Is held from the outer peripheral side.

As shown in FIG. 2, the fuel injection nozzle N is
A first air nozzle cylinder 10, a fuel nozzle cylinder 11 fitted on the outer periphery of the first air nozzle cylinder 10, a second air nozzle cylinder 12 surrounding the fuel nozzle cylinder 11, and a second air nozzle cylinder 12 And a third air nozzle cylinder 13 that surrounds each of the injection holes 10c to 13c concentrically with the injection holes 10c to 13c facing the combustion chamber 3.
Are arranged in the order of the first air nozzle cylinder 10, the fuel nozzle cylinder 11, the second air nozzle cylinder 12 and the third air nozzle cylinder 13 along the axial direction toward the combustion chamber 3 side.

As shown in FIGS. 2 to 4, a fuel / air distribution block 15 is fitted to the upstream ends of the first air nozzle cylinder 10 and the fuel nozzle cylinder 11. First air nozzle cylinder 10
The upstream side of the air passage 16 extends to the fuel / air distribution block 15, and a plurality of air inlet holes 17 (swirl means) connected to the upstream portion of the air passage 16 are provided in the air passage 16.
Is provided in the fuel / air distribution block 15 along the tangential direction of, and when the high pressure air of the compressed air chamber 2 is supplied to the air passage 16 through these air inlet holes 17, a swirling flow of air is generated in the air passage 16. It is like this. Airway 16
Is a tapered narrowing portion 10 in front of the injection hole 10c.
The inner peripheral surface of the injection hole 10c is formed by the cylindrical straightening surface 20 which is continuous with the small diameter end of the narrowed portion 10b.

The fuel / air distribution block 15 has a fuel chamber 25 and a plurality of (two in the illustrated example) fuel passages extending from the fuel chamber 25 and opening at the front end surface of the fuel / air distribution block 15. And a hole 26 is provided in the fuel chamber 25.
A branch pipe 28a of a fuel manifold 28 that distributes the fuel discharged from the fuel pump 27 is connected.

In each of the fuel through holes 26, the front end is formed on the outer peripheral surface of the first air nozzle cylinder 10 and the fuel nozzle cylinder 11 facing each other, that is, the outer peripheral surface of the first air nozzle cylinder 10 in the illustrated example. A fuel groove 29 (see FIG. 3) that opens inside is provided. The fuel groove 29 has a thread groove portion 29a (swirler means) inclined in the circumferential direction at least on the downstream side, and imparts a swirling flow to the fuel passing through the thread groove portion 29a. At this time, the thread groove portion 29a and the air inlet hole 17 are formed so that the swirling direction of the fuel and the swirling direction of the air in the air passage 16 are opposite to each other.

The fuel nozzle cylinder 11 is the first air nozzle cylinder 1
Cylindrical surface 11a fitted to the outer peripheral surface of 0, and the cylindrical surface 11a
tapered portion 11 connected to the end of the combustion chamber 3 side of a
b and the injection hole 1 connected to the small diameter end of the narrowed portion 11b
1c, and the thread groove portion 29a opens toward the taper portion 11c. The inner peripheral surface of the injection hole 11c is formed into a cylindrical straightening surface 21, and the inner diameter D2 thereof is set to be equal to or slightly larger than the inner diameter D1 of the injection hole 10c of the first air nozzle cylinder 10.

The injection hole 12c of the second air nozzle cylinder 12 is formed to have a diameter smaller than that of the cylindrical inlet portion 12a thereof, and they are connected by a tapered narrowed portion 12b.
The inlet portion 12a is provided with a plurality of swirler walls 32 (swirler means) for giving the air passing therethrough a swirling flow in the same direction as the swirling flow of the air in the first air nozzle cylinder 10, and the injection hole 12c. The inner peripheral surface of is formed on the rectifying surface 22 having a cylindrical shape or on the upstream side thereof.

Further, the injection hole 13c of the third air nozzle cylinder 13
Are formed to have a diameter smaller than that of the cylindrical inlet portion 13a, and they are connected by a tapered narrowed portion 13b. The taper angle β of the narrowed portion 13b is set to be larger than the taper angle α of the narrowed portion 12b of the second air nozzle cylinder 12. The inlet portion 13a of the third air nozzle cylinder 13 is also provided with a plurality of swirler walls 33 (swirler means) that imparts to the air passing therethrough a swirl flow in the same direction as the swirl flow of air in the first air nozzle cylinder 10. The twist angle of the swirler wall 33 is set to be larger than the twist angle of the swirler wall 32 of the second air nozzle cylinder 12. Also this third
The inner peripheral surface of the injection hole 13c of the air nozzle cylinder 13 is also formed on the cylindrical straightening surface 23.

Next, the operation of this embodiment will be described.

During operation of the gas turbine, the high-pressure fuel distributed from the fuel manifold 28 to the fuel chamber 25 of the first air nozzle cylinder 10 sequentially passes through the fuel through hole 26 and the fuel groove 29, and then the injection hole of the fuel nozzle cylinder 11. 11c, but fuel groove 2
When passing through the screw groove portion 29a of 9, the turning is forced.
The fuel thus swirled is the fuel nozzle cylinder 1
After increasing the flow velocity while moving the narrowed portion 11b of 1,
The flow is rectified by the flow regulating surface 21 of the injection hole 11c into a cylindrical film-like flow, and jets toward the combustion chamber 3.

On the other hand, the high-pressure air pressure-fed from the compressor (not shown) to the compressed air chamber 2 is used for the air inlet hole 17 of the first air nozzle cylinder 10 and the second and third air nozzle cylinders 12, 1.
3 into the inlet portions 12a and 13a.

Thus, the high-pressure air that has flowed into the air inlet hole 17 of the first air nozzle cylinder 10 travels in the air passage 16 while swirling as described above, and increases in flow velocity at the narrowing portion 10b,
After being rectified by the rectifying surface 20, it is jetted at high speed toward the injection hole 11c of the fuel nozzle cylinder 11. Moreover, since the swirling direction of the jet air is opposite to the swirling direction of the cylindrical film-like fuel flow jetting from the fuel nozzle cylinder 11, the swirling flow of the air jetted from the first air nozzle cylinder 10 is It violently collides with the cylindrical film-like fuel flow ejected from the nozzle cylinder 11, and while effectively atomizing the fuel, it mixes with it to produce a good air-fuel mixture.

The high-pressure air flowing into the second air nozzle cylinder 12 is swirled when passing through the swirler wall 32, the flow velocity is increased at the narrowing portion 12b, and the flow is rectified by the rectifying surface 22, and then is diverted into the combustion chamber 3. The swirling flow of the air jetting and strengthening the swirling force while colliding from the outer peripheral side of the air-fuel mixture, further mixes the fuel in the air-fuel mixture while further atomizing it. As a result, the air-fuel ratio of the air-fuel mixture in the combustion chamber 3 is made uniform, which can contribute to the improvement of ignitability and fuel economy.

By the way, the air having a high swirling velocity ejected from the second air nozzle cylinder 12 tries to spread to a wide angle by the action of centrifugal force, and if left unattended, the mixture spray pattern becomes a wide angle. However, the air ejected from the third air nozzle cylinder 13 suppresses the spray pattern of the air-fuel mixture into a predetermined conical shape.

That is, the high-pressure air flowing into the third air nozzle cylinder 13 is swirled when passing through the swirler wall 33 of the inlet portion 13a, the flow velocity is increased at the narrowing portion 13b, and after being rectified at the rectifying surface 23. , Is jetted into the combustion chamber 3, but the twist angle of the swirler wall 33 is larger than the twist angle of the swirler wall 32 of the second air nozzle cylinder 12, and the narrowed portion 13b
The taper angle β of is the narrowed portion 1 of the second air nozzle cylinder 12.
Since it is larger than the taper angle α of 2b, it is possible to promote the mixing of the outer peripheral portion of the spray pattern of the air-fuel mixture mainly by the air ejected from the third air nozzle cylinder 13, and to improve the ignitability and flame holding property.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, the combustion chamber 3 can be configured as a can type or a cannula type.

[0027]

As described above, according to the first feature of the present invention, the first air nozzle cylinder is arranged in the central portion, and the fuel nozzle cylinder, the second air nozzle cylinder and the third air nozzle are provided on the outer periphery thereof. The cylinders are sequentially arranged concentrically, and the first chamber opens in the combustion chamber.
The nozzle holes of the air nozzle cylinder, the fuel nozzle cylinder, the second air nozzle cylinder and the third air nozzle cylinder are offset in that order toward the combustion chamber along the axial direction, and the fuel manifold is connected to the inlet of the fuel nozzle cylinder. However, the inlets of the first to third air nozzle cylinders are open to the compressed air chamber, and the swirler means for imparting a swirl flow to the fuel or air passing through the fuel and air nozzle cylinders and immediately before each injection hole. In a fuel injection nozzle for a gas turbine, which is provided with a tapered narrowed portion, a cylindrical straightening surface is formed on the inner surface of the injection hole of the fuel nozzle cylinder so as to form the fuel ejected from the injection hole into a cylindrical film shape. That is, the injection hole of the first air nozzle cylinder is formed so that the air flow from the injection hole collides with the cylindrical film-like fuel ejected from the injection hole of the fuel nozzle cylinder, and The twist direction of the swirler means and the Since the twisting directions of the swirler means in the cylinder are set to be opposite to each other, the fuel ejected from the fuel nozzle cylinder and the air ejected from the injection hole of the first air nozzle cylinder violently collide with each other, and the fine particles of fuel are And the mixture of fuel and air can be effectively performed, and the atomization of the fuel can be further promoted by the air ejected from the second air nozzle cylinder, which can improve the ignitability and the fuel economy. Can contribute to improvement.

According to the second feature of the present invention, in addition to the first feature, the twist direction of the swirler means in the second air nozzle cylinder and the twist direction of the swirler means in the third air nozzle cylinder are defined. In the same direction, the twist angle of the swirler means in the third air nozzle cylinder is set to be larger than the twist angle of the swirler means of the second air nozzle cylinder, and the taper angle of the narrowing portion of the second air nozzle cylinder is set. Since the taper angle of the narrowed portion of the third air nozzle cylinder is set to be larger than that of the third air nozzle cylinder,
It is possible to promote the mixing of the outer peripheral portion of the spray pattern of the air-fuel mixture and improve the ignitability and flame holding property.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a gas turbine including a fuel injection nozzle of the present invention.

FIG. 2 is an enlarged vertical sectional view of the fuel injection nozzle.

FIG. 3 is a side view of a first air nozzle cylinder in the fuel injection nozzle.

4 is a sectional view taken along line 3-3 of FIG.

[Explanation of symbols]

2 ... Compressed air chamber 3 ... Combustion chamber 10 ... First air nozzle cylinder 10b ... First air nozzle cylinder narrowing portion 10c ... First air nozzle cylinder jet Hole 11 ... Combustion nozzle cylinder 11b ... Narrowing portion of combustion nozzle cylinder 11c ... Injection hole 12 of combustion nozzle cylinder ... Second air nozzle cylinder 12b ... Narrowing of second air nozzle cylinder Portion 12c ... Injection port 13 of second air nozzle cylinder ... Third air nozzle tube 13b ... Narrowing portion of third air nozzle tube 13c ... Injection hole 17 of third air nozzle tube ... ..Swirl means (air inlet hole) of the first air nozzle cylinder 20 ..... Straightening surface 21 of the injection hole of the first air nozzle cylinder ..... Straightening surface 22 of the injection hole of the combustion nozzle cylinder .. Nozzle straightening surface 23 of the second air nozzle cylinder ... Nozzle straightening surface 28 of the third air nozzle cylinder -Fuel manifold 29a: swirler means for the fuel nozzle cylinder (thread groove)

Claims (2)

[Claims] 1. A first air nozzle cylinder (10) is arranged in the central portion, and a fuel nozzle cylinder (11), a second air nozzle cylinder (12) and a third air nozzle cylinder (13) are sequentially arranged on the outer periphery thereof. Each of a first air nozzle cylinder (10), a fuel nozzle cylinder (11), a second air nozzle cylinder (12) and a third air nozzle cylinder (13) which are arranged concentrically and open to the combustion chamber (3) The injection holes (10c to 13c) are offset in that order along the axial direction toward the combustion chamber (3) side, and the fuel manifold (28) is connected to the inlet of the fuel nozzle cylinder (11). Three
The inlet of the air nozzle cylinder (10, 12, 13) is opened to the compressed air chamber (2), and each fuel and air nozzle cylinder (10-1)
3), a swirler means (17, 29a, 32, 33) for imparting a swirl flow to the fuel or air passing through it, and a tapered narrowing portion (10b) located immediately before each injection hole (10c to 13c). To 13b), a fuel injection nozzle for a gas turbine, in which the fuel injected from the injection hole (11c) is formed into a cylindrical film on the inner surface of the injection hole (11c) of the fuel nozzle cylinder (11) The air flow from the injection hole (10c) passes through the injection hole (11c) of the fuel nozzle cylinder (11) through the injection hole (10c) of the first air nozzle cylinder (10) without forming the cylindrical straightening surface (21). The twisting direction of the swirler means (29a) in the fuel nozzle cylinder (11) and the swirler means (17) in the first air nozzle cylinder (10) are formed so as to collide with the jetted cylindrical film-like fuel. Set the twist direction of Wherein the fuel injection nozzle for a gas turbine. 2. The fuel injection nozzle for a gas turbine according to claim 1, wherein the twisting direction of the swirler means (32) in the second air nozzle cylinder (12) and the third air nozzle cylinder (1).
The twisting direction of the swirler means (33) of 3) is set to the same direction, and the twisting angle of the swirler means (32) of the second air nozzle tube (12) is larger than the twisting angle of the third air nozzle tube (1).
3), the twist angle of the swirler means (33) is set to be large, and the narrowing portion (1) of the second air nozzle cylinder (12) is set.
2b) taper angle (α), the third air nozzle tube (1
A fuel injection nozzle for a gas turbine, characterized in that the taper angle (β) of the narrowed portion (13b) of 3) is set to be large.