JPH01234716A - Gas turbine burner - Google Patents

Abstract

PURPOSE:To maintain the temperature of a tail pipe shell surface less than specified, by installing a guide wall which partially covers said tail pipe and an air passage to the rest of the tail pipe within the tail pipe shell surface. CONSTITUTION:A tail pipe guide inner wall 2, which forms a ring-shaped passage 4 to supply air to a liner, is installed around the outside of a tail pipe 1. Air velocity is controlled so that the wall surface of the tail pipe may be kept at a temperature less than specified. The air velocity can be selected by adjusting the clearance between the tail pipe and the tail pipe guide wall so as to enhance cooling performance. An air passage inlet 6 is installed to the parts which are not covered with the tail pipe guide wall 2. While an air passage 5 provided with an air passage outlet 7 is installed to the parts covered with the tail pipe guide wall 2 within the wall surface of the tail pipe 1. The ring-shaped passage 4 formed by the tail pipe 1 and the tail pipe guide wall 2 is provided with a projecting section 8 so as to narrow the passage. This construction makes it possible to accelerate the cooling of the tail pipe, since cooled air is flowing inside the air passage within the tail pipe wall surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas turbine combustor transition piece, and more particularly to a cooling structure for a high-temperature gas turbine combustor transition piece where the combustor exit gas temperature is high.

[Conventional technology]

As shown in FIG. 2, the gas turbine combustor includes a compressor 13.
Air pressurized in the liner 1 and fuel pressurized in a separate system are
1, the gas is combusted to generate high-temperature gas, and the gas is guided to the turbine stationary blade 11 via the transition pipe 1. The temperature of the combustion gas flowing inside the liner 10 and transition piece 1 is equal to or higher than the melting temperature of the metal materials that make up the liner and transition piece. Air is also allowed to flow inside for cooling.

In the figure, 9 is the fuel nozzle, 12 is the compressor diffuser, and the transition piece 1 is, as shown in Figure 3, the gas passage area is the largest at the entrance of the transition piece near the liner 10, and the closer it is to the turbine stationary blade 11, the more the gas passage area is 0 The heat transfer coefficient α of convective heat transfer that governs the heat input to the transition tube wall surface has a relationship with the gas flow velocity U of ααU0・6, and the transition tube inner wall heat transfer coefficient distribution is the fourth It will look like the figure. Therefore, if the heat transfer coefficient of the cooling air around the outer periphery of the transition tube is constant, the wall surface temperature of the transition tube will be highest at the portion near the turbine station R11. In order to lower the temperature of the transition tube wall surface, Japanese Utility Model Application No. 61-34364 provides a guide wall 2 on the outer periphery of the transition tube 1, as shown in FIG. 2, and furthermore, cooling fins 14 are provided on the outer peripheral wall of the transition tube. It is set up.

[Problem to be solved by the invention]

When such a cooling structure is used in the reverse flow multi-can combustor shown in FIG.
covers only the part of the transition piece 1 near the liner 10, and the part near the turbine stationary blade 11 is less likely to restrict the airflow around the transition piece.
This is the part where the M surface temperature tends to be high, and it is
In Japanese Patent No. 4364, cooling fins 14 are provided to enhance the cooling effect. However, the provision of the fins increases the fluid resistance near the wall surface, and there is a sufficient air passage around the fin's outer periphery, and the air flowing into the transition guide wall 2 flows between the fins. It flows easier,
The cooling performance is worse than the calculated value due to a simple increase in surface area.
Even if the fin surface area is increased, the wall surface temperature will not fall below a certain value.

An object of the present invention is to maintain the transition pipe wall surface temperature below a necessary temperature.

[Means to solve the problem]

The above purpose is to provide a guide wall that covers a part of the transition piece at a predetermined distance from the outer peripheral wall of the transition piece, and in the remaining part of the transition piece, air is allowed to flow from the part not covered by the guide wall to the part covered by the guide wall. This is achieved by providing a passage in the wall of the transition piece as required.

[Effect]

The liner supply air that flows between the transition piece and the transition piece guide wall can be adjusted by adjusting the gap between the transition piece and the transition piece guide wall to select the air flow velocity and improve the cooling performance. Additionally, an air passage is provided within the wall of the tail tube.

The entrance of this air passage is provided in a position that is not covered by the transition tube guide wall, and at the position covered by the transition tube guide wall, the transition tube type in-plane air is By providing the passage outlet, cooling air flows through the transition tube-shaped in-plane air passage, and cooling of the transition tube can be promoted.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. A transition tube guide wall 2 forming an annular passage 4 for flowing air to be supplied to the liner 10 is provided around the outer periphery of the transition tube 1 of the reverse flow multi-can combustor. , that is, adjust the air passage area. Here, the gap between the transition tube and the adjacent transition tube gradually narrows from the liner 10 side to the turbine stationary blade 11 side, and providing the transition tube guide wall 2 that completely covers the transition tube 1 is structurally necessary. Because it would be difficult, if the transition tube guide wall 2 is moved halfway, the range in which the cooling effect of the transition tube can be adjusted is the part covered by the transition tube guide wall 2 and its vicinity, and other Particularly in the part corresponding to the outer circumferential side of the turbine, the air flow velocity around the transition piece is low and the combustion gas flow velocity inside the transition piece is high, so the temperature of the wall surface of the transition piece becomes high. Therefore, an air passage 6 is provided in a portion not covered by the transition piece guide wall 2, and an air passage 5 having an air passage outlet lower is provided within the wall surface of the transition piece 1 in a portion covered by the transition piece guide wall 2. A protrusion 8 is provided on the upstream side of the air passage outlet 6 to narrow the annular passage 4 formed by the transition piece 1 and the transition piece guide wall 2. In order for air to flow through the air passage 5 provided in the transition tube wall surface, a pressure difference is required between the inlet 6 and the outlet lower, but since the output lower is in a position covered by the transition tube guide wall 2, this Since the air supplied to the liner 10 flows at high speed and in large quantities on the surface, the external pressure on the transition piece surface is low, and the air flows inside the air passage 5 from the inlet 6 to the outlet lower. Providing the protrusion 8 on the transition piece 1 promotes this effect. air passage 5
When air flows through the air, the heat transfer coefficient αゎ has the following relation to the air flow velocity U: ahex: U''. When the surface area of the air passages is a, the cooling performance due to the provision of the air passages is expressed as 1 + a□ α 0 , and the cooling performance can be selected depending on the number and cross-sectional area of the air passages 5.

FIG. 6 shows a modification of the present invention. The wall thickness of the transition tube wall at the portion where the air passage 5 is provided in the wall surface of the transition tube is increased as a whole, and the plate thickness is suddenly decreased from the lower air passage ratio. Air from the air passage 5 is made to flow approximately parallel to the cylinder wall surface. FIG. 7 shows another modification. This example is a case where there is no protrusion 8 shown in FIG.
The area of the annular passage formed by the transition piece 1 and the transition piece guide wall 2 is not changed suddenly. FIG. 5 is a cross-sectional view of the transition piece 1 having the air passage 5, showing a state in which the transition piece 1 and the cover plate 3 are completely joined. Note that the air passage 5 can also be provided in the transition piece 1.

〔Effect of the invention〕

According to the present invention, since the entire amount of air after cooling the transition piece can be supplied to the liner, the transition piece can be cooled with almost no effect on the overall performance of the combustor.

[Brief explanation of the drawing]

Fig. 1 is a partial longitudinal cross-sectional view of a transition piece according to an embodiment of the present invention;
The figure is a vertical cross-sectional view of the entire combustor section of a conventional example, Figure 3 is a transition tube cross-sectional area distribution diagram showing changes in the area of the gas passage inside the transition tube, and Figure 4 is a diagram showing the heat transfer coefficient of combustion gas flowing inside the transition tube. The transition pipe inner wall heat transfer coefficient distribution diagram, Figure 5 is a cross-sectional view taken along the ■-■ arrow in Figure 1,
FIG. 6 is a vertical sectional view of the tail tube part of the second embodiment of the present invention, and FIG.
The figure is a longitudinal cross-sectional view of the tail tube portion of a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Transition tube, 2... Transition tube guide wall, 3... Cover plate, 4... Annular passage, 5... Air passage, 6... Air passage entrance, 7... Air Passage exit, 8...Protrusion, 9
...Fuel nozzle. Fig. 1 Fig. 2 Fig. 3 A big problem with the entrance of the tail tube or 5 (-) Fig. 4 left

Claims (1)

[Claims] 1. Air pressurized by a compressor and fuel pressurized by a separate system are guided to a combustor liner, combustion is allowed to proceed within the combustor liner, and the combustion gas generated here is In a gas turbine that obtains output by being guided to a turbine via a transition piece, a guide wall is provided surrounding a part of the transition piece at a predetermined distance from an outer peripheral wall of the transition piece, and the guide wall and the transition piece are connected to each other. All or part of the air supplied to the combustor liner flows through a passage formed by a passageway having an inlet in a portion of the transition piece not surrounded by the guide wall, and having an inlet in a portion of the transition piece that is not surrounded by the guide wall. A gas turbine combustor characterized in that a plurality of air passages each having an outlet on the guide wall side of the enclosed portion are provided inside the wall surface of the transition piece.