Cooling structure of a combustor tail tube

Details Cooling structure of a combustor tail tube Cooling structure of a combustor tail tube

2001-04-12

2003-04-29

Kim, Ted (Department: 3746)

Power plants

Combustion products used as motive fluid

Combustion products generator

C060S757000, C060S760000

Reexamination Certificate

active

06553766

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cooling structure of a combustor tail tube for a gas turbine.
2. Description of the Related Art
As a gas turbine combustor, recently a steam cooling type combustor low in NO
x
emission, even in a gas turbine of 1500° C. class, for example, is drawing attention. By cooling the combustor wall by steam, the air hitherto used for cooling the wall can be used for combustion, and in spite of the high temperature of the gas turbine, the premixed combustion temperature can be suppressed to the level of air-cooled combustor, so that low NO
x
is realized.
Such steam cooling is employed in the cooling of, for example as shown in
FIG. 9
, a tail tube
4
of a multi-nozzle type premixed combustor
3
. Premixed flame forming nozzles
2
for forming and injecting a premixed gas of main fuel and combustion air are divided and disposed in plural positions around a cone
1
for forming a diffusion flame by reaction between pilot fuel and combustion air.
According to this structure, the cooling steam is first supplied into the middle part of the tail tube
4
in the longitudinal direction (see manifold
6
b
) from the cooling jackets
5
(see
FIG. 10
) and manifold
6
b
formed inside the wall of the tail tube
4
. It is divided in the upstream and downstream direction with regard to the gas flow indicated by arrows in the diagram to cool the wall surface, and is collected from the inlet (see manifold
6
a
) and outlet (see manifold
6
c
) of the tail tube
4
. A reverse flow of cooling steam is also known, that is, the cooling steam is first supplied from the inlet (see manifold
6
a
) and outlet (see manifold
6
c
) of the tail tube
4
, then flows into the middle part (see manifold
6
b
) to cool the wall surface, and is collected from the middle part.
The cooling jacket
5
is formed, as shown in
FIG. 10
, by processing a groove (see groove processing part “a”) of width D
1
and depth D
2
in one wall
4
a
of the tail tube
4
of double wall structure, and brazing the groove side to other wall
4
b
(see brazing part “b”).
In this conventional cooling structure of a combustor tail tube, however, although the temperature conditions generally differ locally, with respect to an elevated position of metal temperature at the inner side (rotor side) and lateral side (opposite sides of adjacent tail tubes) from the outer side (casing side) of the tail tube
4
formed in a rectangular shape at the outlet side, the size (passage sectional area) of the cooling jackets
5
is set uniformly on the entire circumference. The flow rate distribution of cooling steam to necessary parts is thus set regardless of the metal temperature, and cracks are likely to be formed at four corners of the outlet of the tail tube
4
due to thermal deformation caused by increases of thermal stress by uneven metal temperatures and a lack of cooling in the outlet (in particular the flange) of the tail tube
4
.
The invention is devised in light of the above background, and it is hence an object thereof to present a cooling structure of combustor tail tube capable of preventing the formation of tail tube cracks by decreasing the thermal stress and preventing thermal deformation, thus extending the service life.
SUMMARY OF THE INVENTION
To solve the above problems, the invention presents a cooling structure of combustor tail tube forming a multiplicity of cooling jackets extending in the longitudinal direction of a tail tube of a gas turbine combustor along the entire circumference of a tail tube wall. The passage sectional area of cooling jackets varies depending on the metal temperature of the tail tube parts.
Preferably, the passage sectional area of the cooling jackets formed at the rotor side wall and the mutually opposite side walls of the adjacent tail tube is formed larger than the passage sectional area of the cooling jackets formed at the casing side wall of the tail tube.
Preferably, the cooling jackets are extended from the root of the flange attached to the peripheral edge of the outlet of the tail tube in the flange height direction, and are pulled back after the cooling medium is supplied in the area.
Preferably, an annular cooling passage is formed to surround the outlet in the front portion of the flange attached to the edge of the outlet of the tail tube, and the cooling medium is directly supplied into the cooling passage without cooling the tail tube wall.
Preferably, the tail tube is formed in a double wall structure, a groove is processed in one wall, the groove side is bonded with the other wall to form a cooling jacket, and the groove side wall is disposed at the inner wall side to be exposed to combustion gas.
Preferably, the cooling medium is supplied from the combustion gas outlet of the tail tube, and the cooling medium is collected from one position at the combustion gas inlet side.


REFERENCES:
patent: 3572031 (1971-03-01), Szetela
patent: 4719748 (1988-01-01), Davis, Jr. et al.
patent: 5647202 (1997-07-01), Althaus
patent: 5724816 (1998-03-01), Ritter et al.
patent: 5822853 (1998-10-01), Ritter et al.
patent: 5906093 (1999-05-01), Coslow et al.
patent: 6018950 (2000-02-01), Moeller
patent: 6220036 (2001-04-01), Inada et al.
patent: 6282905 (2001-09-01), Sato et al.
patent: 0 203 431 (1986-12-01), None
patent: 0 725 253 (1996-08-01), None
patent: 0 815 995 (1998-01-01), None
patent: 0 972 992 (2000-01-01), None
patent: 410288048 (1998-10-01), None
patent: 2984427 (1999-09-01), None
patent: 2000-145479 (2000-05-01), None

Affiliated with

Also associated with

Rating

Cooling structure of a combustor tail tube does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Cooling structure of a combustor tail tube, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cooling structure of a combustor tail tube will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3001180