Power plants – Combustion products used as motive fluid – Combustion products generator
Reexamination Certificate
1999-11-10
2001-09-04
Thorpe, Timothy S. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combustion products generator
C060S754000, C060S756000, C060S757000, C060S760000
Reexamination Certificate
active
06282905
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a cooling structure of gas turbine combustor and more particularly to a cooling structure in which a high temperature portion to be cooled of gas turbine combustor, such as a wall portion and a pilot cone, is made in a double structure of an outer plate and an inner plate so that cooling medium, such as air or steam, flows therein with enhanced cooling efficiency.
2. Description of the Prior Art
FIG. 17
is a schematic cross sectional side view showing structure of a gas turbine combustor and a cooling system thereof in the prior art, wherein FIGS.
17
(
a
) and
17
(
b
) show examples of air cooled system and FIG.
17
(
c
) shows an example of steam cooled system. If description thereon is outlined, in FIG.
17
(
a
), numeral
100
designates a pilot nozzle, which injects pilot fuel for combustion thereof, numeral
101
designates a main nozzle, which, being called an annular nozzle type, is arranged in plural pieces around a pilot inner tube
102
and injects main fuel to be ignited by combustion of the pilot fuel in the pilot inner tube
102
. Numeral
103
designates a main inner tube, numeral
104
designates a connecting tube and numeral
105
designates a tail tube, and combustion gas of high temperature produced by combustion of the main fuel flows through these portions to be led into a combustion gas path of gas turbine. Numeral
106
designates an air by-pass valve, which causes surplus air coming from a compressor at a low load time to enter the tail tube
105
via a by-pass duct and to escape into the combustion gas path. In said type of combustor, there is employed a cooling structure using air in a wall of the tail tube
105
, as described later with reference to FIG.
18
.
In a combustor of FIG.
17
(
b
), which is called a multiple nozzle type, numeral
107
designates a pilot nozzle, and a main nozzle
108
is arranged in plural pieces therearound. Main fuel is injected from the main nozzle
108
into an inner tube
109
to be ignited by combustion of pilot fuel injected from the pilot nozzle
107
. Numeral
110
designates a tail tube and numeral
106
designates an air by-pass valve. In this type of combustor also, wall interior of the tail tube
110
is cooled by air, as described later with reference to FIG.
18
.
Combustor of FIG.
17
(
c
) is an example where a steam cooled system is employed in the multiple nozzle type combustor.
In FIG.
17
(
c
), numeral
111
designates a pilot nozzle, numeral
112
designates a main nozzle, which is arranged in plural pieces around the pilot nozzle
111
, and numeral
113
designates a swirler holder. Numeral
114
designates a tail tube, which is made integrally with an inner tube and is connected to the swirler holder
113
so that combustion gas of high temperature is led therethrough into the combustion gas path of gas turbine. In a wall of the tail tube
114
, there are provided a multiplicity of steam passages for cooling therearound. Numeral
115
designates a steam supply passage and numerals
116
,
117
designate steam recovery passages, respectively. Steam
200
for cooling flows through the steam supply passage
115
to be supplied into the steam passages in the wall of the tail tube
114
for cooling of wall interior thereof and is then recovered into the steam recovery passages
116
,
117
provided at respective end portions of the tail tube
114
as steam
201
,
202
to be returned to a steam producing source for an effective use thereof.
FIG. 18
is a partially cut away perspective view of the wall of the combustor tail tubes
105
,
110
shown in FIGS.
17
(
a
) and
17
(
b
). In
FIG. 18
, the wall is made in a double structure in which an outer plate
120
and an inner plate
123
are jointed together being lapped one on another. The outer plate
120
constitutes an outer surface of the tail tube and has a multiplicity of grooves
121
, each having a common cross sectional shape, provided therein substantially along a flow direction of the combustion gas. The outer plate
120
is jointed together with the inner plate
123
so that opening faces of the grooves
121
of the outer plate
120
are closed in the jointed plane. Also, in the outer plate
120
, there are bored a multiplicity of air inlet holes
122
, each communicating with the grooves
121
and being arranged with a predetermined interval between the air inlet holes
122
along each of the grooves (
2
).
The inner plate
123
has a multiplicity of air outlet holes
124
bored therein so as to communicate with the grooves
121
of the outer plate
120
, when the outer plate
120
and the inner plate
123
are so jointed together. Each of the air outlet holes
124
is provided so as to be arranged in a mid position of two mutually adjacent air inlet holes
122
along each of the grooves
121
. The outer plate
120
and the inner plate
123
are made of a heat resistant material, such as Hastelloy X, Tomilloy and SUS material, and the jointing thereof is done by diffusion welding in which a hot pressure welding is done under heat and pressure.
In the mentioned wall structure, air
300
for cooling entering the air inlet holes
122
from around the tail tube flows into the respective grooves
121
for cooling of the wall interior and flows out of the air outlet holes
124
of the respective grooves
121
to enter the tail tube as air
301
. Such grooves
121
, and air inlet holes
122
and air outlet holes
124
both communicating with the grooves
121
, are provided in plural pieces in the entire circumferential wall of the tail tube and the air outside of the tail tube is supplied thereinto to flow in the wall interior for cooling of the entire portion of the tail tube wall and flows out of the respective air outlet holes
124
to be mixed into the combustion gas in the tail tube.
FIG. 19
is an enlarged cross sectional side view of the steam cooled type combustor shown in FIG.
17
(
c
). As shown there, the swirler holder
113
of combustor, which is fitted to a turbine cylinder
130
, is coupled with the tail tube
114
which is made integrally with the inner tube. In an entire circumferential wall of the tail tube
114
, there are provided a multiplicity of steam passages
118
,
119
substantially along a flow direction of the combustion gas. Each of the steam passages
118
,
119
has a common cross sectional shape and communicates with the steam supply passage
115
. A portion of the steam
200
in the steam supply passage
115
is supplied toward the nozzle side through the steam passages
118
for cooling of the wall to be recovered into the steam recovery passage
116
as the steam
201
. Remainder of the steam
200
is supplied toward the downstream side through the steam passages
119
for cooling of the wall to be recovered into the steam recovery passage
117
as the steam
202
.
FIG. 20
is a cross sectional side view of an upper half portion of a pilot cone fitted to an end each of the pilot nozzles of the combustors shown in FIGS.
17
(
b
) and
17
(
c
). In
FIG. 20
, the pilot nozzle is provided in the central portion of the combustor inner tube and a pilot cone
130
is fitted to an end of the pilot nozzle. The pilot cone
130
opens in a funnel-like shape, as shown there, and a guide ring
131
is provided around the pilot cone
130
for support thereof. For supporting the pilot cone
130
fixedly, welding is applied to around a connecting portion
132
between the pilot cone
130
and the guide ring
131
with a predetermined interval between the welded places.
In the central portion of the pilot cone
131
, pilot fuel injected from the pilot nozzle burns and combustion gas
140
of high temperature flows there. A portion of the combustion gas
140
flows along a tapered wall inner surface of the pilot cone
130
and this wall inner surface is continuously exposed to the high temperature gas. Further, as mentioned above, the plural main nozzles are arranged around the pilot cone
130
and fuel injected therefrom is igni
Nishida Koichi
Sato Yoshichika
Hayes Eric D.
Mitsubishi Heavy Industries Ltd.
Thorpe Timothy S.
Wenderoth , Lind & Ponack, L.L.P.
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