JPH0674415A - Flame holder cooling structure for premixed combustor - Google Patents

Abstract

PURPOSE:To utilize a cooling medium after cooling for the premixed combustion effectively by a method wherein a cooling medium passage is provided in a flame holder of a premixed combustor, and the cooling of a heated part is performed by making the cooling medium flow through the passage. CONSTITUTION:A flame holder 1 with a bag-shaped hollow structure of a flame holder with a bag-shaped double hollow structure is provided at a premixed gas outlet, and a cooling medium 7 is continuously made to flow in the hollow part. After exchanging the heat of a heated part (1c) by the cooling medium 7, the cooling medium 7 is discharged from a cooling medium discharge port 4 which is provided at a more upstream side than a discharge port 11 of a premixed fuel nozzle 10, and is mixed with a fuel which is jetted from the premixed fuel nozzle 10 and air for combustion to create a premixed gas 8. A premixed flame 5 is formed by the flame holder 1 with a bag-shaped hollow structure or a flame holder with a bag-shaped double hollow structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame holder cooling structure for a premixed combustor.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Patent Laid-Open No. 59-12 is available.
As described in 9330, a flame holder (vortex generator) is provided at the outlet of the premix combustor to stabilize the premix flame. Since this flame stabilizer generates a high-temperature circulating flow on the wake side, the flame stabilizer is heated to a high temperature, but its cooling is not taken into consideration, so there is a problem in terms of reliability.

On the other hand, for cooling the combustor liner other than the flame stabilizer, a film cooling method by air or an impingement cooling method is mainly used. Even if this method is used for cooling the flame stabilizer, the heated portion is not heated. The cooled air does not have a structure that can be directly used as combustion air, and a large amount of air is supplied to the premixing section to perform low-temperature combustion with the lean premixed fuel gas to generate nitrogen oxides (NOx). We could not reduce it. Further, the air after cooling the heated portion of the flame stabilizer has a structure in which it is discharged into the combustion chamber and affects the premixed flame, and NOx reduction cannot be achieved. , Sufficient consideration was needed.

[0004]

Even when the conventional film cooling method or impingement cooling method is applied to the flame stabilizer of the premixed combustor, the air after cooling the heated portion is exhausted into the combustion chamber, There was a problem that excess air required for premixed combustion could not be obtained, and lean combustion for low NOx combustion could not be achieved sufficiently.

According to the present invention, the air or fuel necessary for cooling the flame holder of the premixed combustor is used as a cooling medium, and after the flame stabilizer of the premixed combustor is cooled, it is mixed with the premixed fuel to produce an excess amount. An object of the present invention is to obtain a premixed combustor that can obtain air or fuel and can effectively perform premixed combustion, and further reduce NOx.

[0006]

In order to achieve the above object, the present invention has a bag-shaped hollow or bag-shaped double hollow structure having a heated portion at the tip thereof as the internal structure of the flame stabilizer, and the hollow part is Cooling the heated part of the flame stabilizer as a cooling medium flow path,
In addition, a cooling medium discharge port is provided on the upstream side of the fuel injection port of the premixing nozzle to discharge the air or fuel after cooling the heated portion into the premixing flow path, effectively making the cooling medium after cooling the heated portion. It is characterized in that it can be used for premixed combustion.

[0007]

According to the above means, the following functions and functions are exhibited.

(1) The internal structure of the flame holder of the premixed combustor is formed into a bag-shaped hollow or double hollow structure having a heated portion at the tip, and the hollow portion is used as a cooling medium flow passage, and cooling is performed in the flow passage. By continuously flowing the medium, heat exchange is performed to reduce the temperature deviation of the heated portion, the thermal stress due to the temperature change can be relaxed, and the burnout can be prevented.

(2) When the cooling medium after cooling the heated portion is discharged from the cooling medium discharge port provided on the upstream side of the fuel injection port of the premixing nozzle into the premixing passage, and air is used as the cooling medium. In addition, low temperature combustion can be performed due to lean fuel, and effective low NOx is achieved. Alternatively, when a fuel is used as the cooling medium, it can be used as the premixed fuel and can be the same fuel source as the premixed fuel, and the structure does not become complicated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention is shown in FIGS.
1 is a cross-sectional view of a bag-shaped hollow flame stabilizer 1 in a premix combustor, and FIG. 2 is a side view of FIG. The bag-shaped hollow structure
It is composed of an inner wall 1a and an outer wall 1b, and the hollow portion between them is cooling medium flow paths 3a and 3b through which the cooling medium 7 flows. The cooling medium 7 that has continuously flowed through the flow path 3a in the same direction as the premixed gas 8 flows while eliminating the temperature deviation due to heat exchange with the heated portion 1c, and alleviates thermal stress. After the heat exchange, the cooling medium 7 passes through the flow path 3b and is discharged into the premixing flow path 9 from the cooling medium discharge port 4 opened upstream of the jet port 11 of the premixing nozzle 10. Premixed gas 8 mixed with fuel and combustion air in 9
And the premixed flame 5 is formed.

Another embodiment is shown in FIG. FIG. 3 is a cross-sectional view of the flame stabilizer 2 having a bag-shaped double hollow structure in the premixed combustor. The bag-shaped double hollow structure has a double hollow portion constituted by an inner wall 2a and an outer wall 2b, the inner hollow portion of which serves as an inner cooling medium passage 3a, and the outer hollow portion of which serves as an outer cooling medium passage. It also has two channels 3b. The cooling medium 7 that has continuously flowed from the inner cooling medium passage 3a in the same direction as the premixed gas has holes 6 formed in the inner side wall 2a that constitutes the inner cooling medium passage 3a facing the heated portion 1c.
It is discharged to the outer side cooling medium flow path 3b and flows while eliminating the temperature deviation due to heat exchange with the heated portion 1c, thereby alleviating thermal stress. After the heat exchange, the cooling medium 7 passes through the outer cooling medium passage 3b and the cooling medium discharge port 4 opened upstream of the jet port 11 of the premixing nozzle 10 to the premixing passage 9
Is discharged to a premixed gas 8 by mixing with fuel and combustion air in the premixed flow path 9 to form a premixed flame 5.

EXAMPLE Air or fuel can be used as the cooling medium in FIGS. Note that FIG. 4 is an example of a case where the flame stabilizer of the premixed combustor shown in FIG. 3 is adopted as a gas turbine combustor.

[0013]

According to the present invention, the flame stabilizer has a bag-shaped hollow structure or a bag-shaped double-hollow structure to provide a cooling medium passage to flow the cooling medium, and the cooling medium is heated. After part cooling, the cooling medium is discharged into the premixing passage from the cooling medium discharge port provided on the upstream side of the premixing nozzle, and the cooling medium can be effectively used for premixing combustion and mixed with the premixing fuel. As a result, excess air can be obtained and premixed combustion can be performed, thereby achieving low NOx.
When a fuel is used as the cooling medium, the same fuel source as the premixed fuel can be used, and the structure does not become complicated.

Further, by making the structure of the flame stabilizer a bag-shaped hollow or a bag-shaped double hollow structure, it is possible to reduce the thickness of the heated portion, thereby reducing the temperature deviation of the heated portion. In addition, since the amount of free expansion and contraction due to heat is larger than that of the one with a large plate pressure, fatigue fracture due to thermal stress can be reduced. Further, by continuously flowing the cooling medium through the cooling medium flow passage inside the flame stabilizer, it is possible to lower the temperature of the heated portion and further reduce the temperature deviation, so that the thermal stress can be reduced. It is possible to prevent heat loss. Due to the two effects of thinning the heated portion and continuously flowing the cooling medium, it is possible to operate the gas turbine combustor for a long time.

[Brief description of drawings]

FIG. 1 is a sectional view of a bag-shaped hollow flame stabilizer.

FIG. 2 is a side view of the bag-type hollow flame stabilizer shown in FIG.

FIG. 3 is a sectional view of a bag-type double hollow flame stabilizer.

FIG. 4 is an overall cross-sectional view when the embodiment of FIG. 3 is adopted in a gas turbine combustor.

[Explanation of symbols]

1: Bag-shaped hollow flame stabilizer, 1a: inner wall, 1b: outer wall, 1c: heated part, 2: bag-shaped double hollow flame stabilizer,
3a: inner cooling medium channel, 3b: outer cooling medium channel,
4: Cooling medium discharge port, 5: Premixed flame, 6: Inner wall hole, 7: Cooling medium, 8: Premixed gas, 9: Premixed flow path,
10: Premixed fuel nozzle, 11: Premixed fuel nozzle ejection port.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Sato 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Tomio Kuroda 3-chome, Saiwaicho, Hitachi, Ibaraki No. 1 Hitachi Ltd. Hitachi factory (72) Inventor Shigeru Shodohata 4026 Kujimachi, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Yoshikazu Moritomo 3-chome, Saiwaicho, Hitachi City, Ibaraki Prefecture No. 1-1 Hitachi Ltd., Hitachi Works (72) Inventor Kei Ikeda, Keiichi Ikeda 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd. (72) Inventor, Naohiko Iwata Hitachi, Ibaraki Prefecture 3-1, 1-1 Sachimachi Hitachi Ltd. Hitachi factory (72) Inventor Masayuki Taniguchi 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi, Ltd. (72) inventor Iizuka Hitachi City, Ibaraki Prefecture Nobuyuki Saiwaicho Third Street No. 1 No. 1 stock company Hitachi, Ltd. Hitachi in the factory

Claims (4)

[Claims] 1. A premixing combustor having a premixing nozzle and a flame stabilizer provided at a premixing outlet end thereof, wherein the flame stabilizer has a bag-shaped hollow structure having a heated portion at its tip, and the hollow A cooling medium flow passage is formed by a flow passage leading to a heated portion by a portion and a flow passage leading to a discharge port provided upstream of the fuel injection port of the premixing nozzle from the heated portion. Flame stabilizer cooling structure for mixed combustor. 2. A premixing combustor having a premixing nozzle and a flame stabilizer provided at the premixing outlet end thereof, wherein the flame stabilizer has a double hollow structure having a heated portion at its tip, and the inside thereof. The hollow part formed the cooling medium flow path to the heated part, and the outer hollow part formed the cooling medium flow path to the discharge port provided upstream of the fuel injection port of the premix nozzle from the heated part. A flame holder cooling structure for a premixed combustor, which is characterized in that 3. A flame holder cooling structure for a premixed combustor according to claim 1, wherein air is used as a cooling medium. 4. A flame holder cooling structure for a premixed combustor according to claim 1, wherein a fuel is used as a cooling medium.