JPH09303776A - Fuel injection nozzle for gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the retention time by the presence of combustible mixture gas in the main area of an air flow and to avoid the riskiness of a self-ignition by allowing the fuel nozzle hole of a low NOx gas turbine combustor to protrude from a nozzle body wall surface, and disposing its outlet out of the low velocity area of the air flow near the nozzle body wall surface. SOLUTION: The nozzle hole 105 provided at the part of the downstream side from the main swirler 101 of the body wall surface of a main fuel nozzle 102 is projected outward of the body wall surface, and the outlet of the end is disposed out of the low velocity area of the air flow of a velocity boundary layer that the air flow passing the swirler 101 is formed near the body wall surface of the nozzle 102. Since the fuel is injected at the outside of the low velocity area of the air flow formed near the body wall surface of the nozzle 102, combustible premixed gas is formed at the main flow part of the air flow. Accordingly, the fuel concentration in the low velocity area of the air flow can be suppressed to low, and the premixed gas can be effectively prevented from being self-ignited.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel injection nozzle for a gas turbine combustor.

[0002]

2. Description of the Related Art A conventional premixed flame type low NOx combustor capable of burning both gas and liquid fuel, which is conventionally used as a gas turbine combustor, is shown in FIG. 3 shows.

A plurality of pilot combustion nozzles 104 that form a flame portion in the center of the cross section of the combustor, and a cylindrical outer cylinder 106 around the pilot combustion nozzles 104 are provided to form a premixed gas of fuel and air. The main fuel nozzle 102 of is arranged. Pilot combustion nozzle 10
2 is provided with a pilot swirler 103. A main swirler 101, which is arranged around the main combustion nozzle 102 and extends to the outer cylinder 106, is provided at an upstream portion of each main fuel nozzle 102.
A plurality of nozzle holes 105 are formed in the wall surface of the nozzle body on the downstream side of the second main swirler 101.

In this conventional gas turbine combustor, air is supplied from a plurality of main swirlers 101 and one pilot swirler 103, and fuel is supplied to the main fuel nozzles 10.
2. It is supplied from the pilot fuel nozzle 104.

In the main fuel nozzle 102, FIG.
As shown in, the fuel is ejected from the nozzle hole 105 formed in the wall surface of the nozzle body, and is mixed with the air flowing around the outer periphery of the nozzle through the main swirler 101 to form a premixed gas.

The arrows in FIGS. 2 and 3 indicate the flow of fuel and air.

[0007]

In the combustor of the gas turbine as shown in FIGS. 2 and 3, when the fuel whose self-ignition temperature is lower than the combustion air temperature is burned, the vicinity of the wall surface of the nozzle body is If the fuel concentration is in the combustible range in the low velocity region (velocity boundary layer) of the air flow, there is a risk that self-ignition will occur if the residence time is longer than the ignition delay time.

The present invention is intended to provide a fuel injection nozzle for a gas turbine combustor which can solve the above problems.

[0009]

DISCLOSURE OF THE INVENTION In the fuel injection nozzle of a premixed flame type low NOx gas turbine combustor, the present invention has a nozzle hole for fuel projecting from the wall surface of the nozzle body, and its outlet near the wall surface of the nozzle body. It is characterized by being located outside the low speed region of the air flow.

In the present invention, since the outlet of the fuel nozzle hole protruding from the wall surface of the nozzle body is located outside the low speed region of the air flow in the vicinity of the wall surface of the nozzle body, the fuel is jetted directly from the nozzle wall as compared with the conventional case. As a result, the fuel concentration in the velocity boundary layer, which is the low speed region of the air flow, decreases. Therefore, the combustible mixed gas is present in the main flow region of the air flow, the residence time is shortened, and the risk of self-ignition can be avoided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIG. In the present embodiment, in the gas turbine combustor shown in FIGS. 2 and 3, the fuel nozzle hole 105 of the main fuel nozzle is configured as described below, and other parts are not changed, The description is omitted.

That is, in the present embodiment, the nozzle hole 105 provided in the portion of the main wall surface of the main fuel nozzle 102 on the downstream side of the main swirler 101 is provided so as to project outward from the main wall surface, and the outlet at the tip thereof is provided. , Main swirler 10
The air flow passing through No. 1 is located outside the low speed region of the air flow which is the velocity boundary layer formed near the main body wall surface of the main fuel nozzle 102. The arrows in FIG. 1 indicate the flow of fuel and air.

In the present embodiment, the fuel is jetted from the outlet at the tip of the nozzle hole 105 of the main fuel nozzle 102. As described above, the fuel is ejected to the outside of the low speed region of the air flow formed in the vicinity of the main wall surface of the main fuel nozzle 102, so that a combustible premixed gas is formed in the main flow portion of the air flow. Therefore, the fuel concentration in the low speed region of the air flow can be suppressed to a low level, and the premixed gas can be promptly supplied to the flame portion to reliably prevent the premixed gas from self-igniting.

In the embodiment of the present invention, the projecting nozzle hole 105 of the main fuel nozzle 102 is provided on the downstream side of the main swirler 101, but the nozzle hole in the present invention is provided on the upstream side of the main swirler. Alternatively, the fuel concentration in the low speed region (velocity boundary layer) of the air flow near the main body wall surface of the main fuel nozzle can be kept low. However, since it is possible to form a more uniform premixed gas by injecting fuel into the air rectified through the main swirler, as in the embodiment of the present invention, the protruding nozzle holes It is possible to obtain a better effect by providing the downstream side of the main swirler.

[0015]

According to the present invention, the fuel concentration in the low speed region (velocity boundary layer) of the air flow in the vicinity of the wall surface of the nozzle body of the main fuel nozzle is kept low to avoid the risk of self-ignition of the combustible premixed gas. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view of a main fuel nozzle according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a conventional premixed flame type low NOx gas turbine combustor.

FIG. 3 is a cross-sectional view of a main fuel nozzle of a conventional gas turbine combustor.

[Explanation of symbols]

 101 Main Swirler 102 Main Fuel Nozzle 103 Pilot Swirler 104 Pilot Combustion Nozzle 105 Nozzle Hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Nishida 2-1-1 Shinhama, Arai-cho, Takasago-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Takasago Plant

Claims (1)

[Claims] 1. In a fuel injection nozzle of a premixed flame type low NOx gas turbine combustor, a nozzle hole for fuel is projected from a wall surface of a nozzle body, and its outlet is outside in a low speed region of an air flow near the wall surface of the nozzle body. A fuel injection nozzle for a gas turbine combustor characterized by being positioned.