JPS63143422A - Gas turbine combustor - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency of a gas turbine and to hold the metal temperature of each of tail pipes and combustor liners at an allowable value or less, by a method wherein a flow sleeve having a given gap outside of the tail pipe is mounted throughout except both sides located down a line from the tail pipe, and impinge cooling and convection cooling are effected according to a metal temperature. CONSTITUTION:An opening part 16 of a tail pipe flow sleeve 4 is mounted in a range where a velocity of flow of main flow gas in a tail pipe 4 is high and the metal temperature of the wall of the tail pipe 3 is increased. A portion in this range has a structure where fluid for cooling being injected through a plurality of injection nozzles formed in the tail pipe flow sleeve 4 is made to collide against the wall surface of the tail pipe 3 to effect impinge-cooling. An opening part 15 of the tail pipe flow sleeve 4 introduces a remaining amount of the fluid for cooling to the tail pipe flow sleeve 4 in association with an opening part 17 of the side of the tail pipe. The fluid for cooling through the opening parts 15 and 17 is joined with the fluid for cooling through the opening part 16, and flows through a gap between the tail pipe 3 and the tail pipe flow sleeve 4 toward the upper stream side. The tail pipe 3 in this range is convection-cooled by the flow to hold the metal temperature of the wall of the tail pipe 3 at an allowable temperature or less.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a gas turbine combustor, and relates to a flow sleeve structure provided for cooling a transition piece, so as to minimize pressure loss and improve thermal efficiency. This invention relates to an improved combustor structure.

[Prior art]

The cooling structure of the conventional gas turbine combustor transition piece was
4-11443, a cooling sleeve is provided in a part of the combustor transition piece, and cooling is achieved by colliding jets of cooling fluid from a plurality of holes arranged in the cooling sleeve against the surface of the transition piece. The structure was such that the cooled fluid merged with the mainstream gas through a through hole provided downstream of the transition piece.

In the conventional structure described above, a portion of the cooling fluid is consumed to cool the combustor transition piece, so the flow rate of the cooling fluid used to cool the combustor liner decreases, which increases the combustion temperature. You will not be able to do so. Furthermore, after cooling the transition piece, the cooling fluid that flows into the mainstream gas does not mix with the high-temperature part of the mainstream gas, but instead flows into the turbine part while remaining in the two-layered state of the low-temperature part.

This will have a negative effect on the rotor blades and stationary blades of the turbine section.6Furthermore, in order to improve cooling efficiency, the cooling sleeve is fixed to the transition piece by welding, but due to the temperature difference between the transition piece and the cooling sleeve, Thermal stress increases, causing a decline in snobbery.

As an improvement plan to the above conventional example, in the case of a single improvement plan in which a flow sleeve is provided on the entire outer surface of the transition tube and a structure is provided in which one transition tube is cooled by impingement or convection, there are problems in terms of cooling efficiency and reliability. It's good, but it has the following problems.

In the case of a multi-can combustor, multiple combustors are arranged in one circumferential direction.9 In a normal gas turbine, 6 to 14 combustors are arranged in consideration of the ease of assembly and disassembly9. There are many examples of arrays. For this reason, the structure must be such that the circumferential gap between the combustors is limited.

A portion of the cooling fluid from the compressor enters the inside through the flow sleeve on the ventral side and cools the transition piece on the ventral side. The other part passes through the gap between the combustors, wraps around the outer circumference of the flow sleeve, enters the interior through the flow sleeve on the back side, and cools the tail piece on the back side.

The gap between the combustors is further narrowed by adopting a full-surface flow sleeve structure, and due to the pressure loss that occurs when the cooling fluid passes through this gap, the outer and inner circumference of the flow sleeve This will result in a large pressure difference. This pressure difference causes an imbalance in the flow rate of the cooling fluid flowing in from the flow sleeve, creating a high temperature area on the back side. Although it is possible to eliminate this unbalanced inflow of cooling fluid by making the area of the cooling fluid inlet of the flow sleeve in the inner periphery smaller than that in the outer periphery, the pressure loss of the combustor as a whole is increases, and the thermal efficiency of the gas turbine decreases.

[Problem that the invention seeks to solve]

In the above conventional technology, the cooling fluid flows from a plurality of arranged holes in the cooling sleeve attached to the trailing end of the transition piece.
After colliding with the outer wall of the transition tube and cooling the transition tube, the gas flows into the mainstream gas through a through hole provided in the wall of the transition tube. Consuming a part of the cooling fluid for the cold part of the combustor transition piece means that the cooling fluid available for cooling the entire combustor liner is reduced, so the combustor liner metal In order to maintain the temperature at an acceptable level, the combustion gas temperature has to be lowered.

Furthermore, in order to flow the cooling fluid into the transition piece through the cooling sleeve at a predetermined flow rate, it is necessary to create a certain pressure difference between the outside of the cooling sleeve and the inside of the transition piece.
The efficiency of the gas turbine decreases by this amount.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to minimize the loss due to the pressure difference described above, improve the thermal efficiency of the gas turbine, and further improve the thermal efficiency of the transition piece and combustor. The objective is to provide a combustor that can maintain the liner metal temperature below a permissible value.

[Means for solving problems]

The above purpose is to provide a slow sleeve with a certain gap from the outer wall of the transition tube around the entire circumference except for both downstream side surfaces of the transition tube, and to use this flow sleeve to cool the transition tube. The dorsal and ventral parts of the trailing part of the tail piece, where the metal temperature of the tail piece is particularly high due to the large temperature, are cooled by impingement cooling by jets of cooling fluid from multiple holes arranged in the flow sleeve. The area on the side where the metal temperature does not become relatively high is cooled by convection by flowing cooling fluid at a predetermined flow rate between the flow sleeve and the transition piece, and the area on both downstream sides of the transition piece where there is no flow sleeve is This is achieved by providing convective cooling by the flow of discharge air from the compressor.

[Effect]

In the above configuration, the cooling fluid, which is the discharge air from the compressor, can be used most effectively and effectively for cooling the combustor liner and transition piece while maintaining the minimum combustor pressure loss. 1. Since the structure has a flow sleeve with a predetermined gap on the outside of the transition tube around the entire circumference except for both downstream sides of the transition tube, the cooling fluid is controlled by the structure of the transition tube and the temperature of the mainstream gas inside the transition tube. - Impingement cooling and convection cooling are performed together according to the metal temperature determined by the flow velocity.

As a result, the combustion air from the compressor can be used as a cooling fluid for the two transition tubes with minimum pressure loss, resulting in a highly efficient transition tube cooling structure.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The combustor chamber of the gas turbine consists of a combustor liner 1, a combustor liner flow sleeve 2, a combustor tail@3° transition pipe flow sleeve 4, a combustor outer cylinder cover 5. Combustor outer cylinder 6, discharge casing 7, combustor casing 8, turbine casing 9, fuel nozzle 10, spark plug 11, inner barrel 12
It consists of

After the discharge air from the compressor 13 flows into the combustor chamber, it flows between the transition piece 3 and the transition piece flow sleeve 4 through an opening provided in the transition piece flow sleeve 4, cools the transition piece 3, and flows upstream. It flows to the side, is guided by the combustor liner flow sleeve 2, and flows into the interior through an opening provided in the combustor liner 1.

Combustion from the fuel nozzle 10 is ignited and combusted in the combustor liner 1 by the ignition plug 11, and the generated high-temperature gas passes through the combustor liner 11 and the inside of the transition piece 3, and is floated to the turbine 14.
Since the transition piece 3 serves as a transition member between the combustor line 1 and the turbine 14, it has a smooth curved surface that connects the circular shape of the joint with the combustor line 1 to the fan shape of the joint of the turbine 14. It becomes a three-dimensional shape. Therefore, as shown in FIG. 2, the cross-sectional area of the transition piece 3 decreases and changes as it moves from the combustor liner 1 side to the turbine 14. As a result, the flow velocity of the high-temperature mainstream gas inside the transition piece 3 changes greatly due to the change in cross-sectional area shown in Figure 2 and the change in direction due to the shape, and the heat transfer coefficient to the wall inside the transition piece 3 changes. It will have an impact. The relationship between this heat transfer coefficient and the position of the transition piece 3 is shown in FIG. This difference in heat transfer coefficient on the internal mainstream gas side is
This appears as variations in the temperature of the wall metal of transition tube 3. In order to keep the wall metal temperature of the transition piece 3 at a uniform value below the allowable temperature, it is necessary to further strengthen cooling from the outside compared to the upstream side on the downstream side.

FIG. 4 is an enlarged sectional view showing details of a transition piece portion of the combustor chamber shown in FIG. 1. FIG. Cooling fluid from the compressor flows through openings 15, 16, 17 provided in the transition piece flow sleeve 4 to the transition piece 3 and the transition piece flow sleeve 4 for cooling the transition piece 3.
The opening 16 of the single transition tube flow sleeve 4, which is structured to flow between the transition tube 3 and the transition tube 3, is provided in a range where the flow velocity of the mainstream gas in the transition tube 3 is high and the temperature of the transition tube 3 wall metal is particularly high. In this range, cooling fluid from a plurality of nozzle holes arranged in the transition piece flow sleeve 4 collides with the wall surface of the transition piece 3 to perform impingement cooling.

The opening 15 of the transition piece flow sleeve 4, together with the opening 17 on the side of the transition piece, introduces the remaining amount of the cooling fluid into the transition piece flow sleeve 4. The cooling fluid from the openings 15 and 17 merges with the cooling fluid from the opening 16 to form the transition tube 3.
and the transition piece flow sleeve 4 toward the upstream side (upper left in the figure). The transition piece 3 in this range is convectively cooled by this flow, and the temperature of the wall metal of the transition piece 3 is kept below the permissible temperature.

After the cooling fluid from the compressor 13 enters the combustor chamber, it directly flows into the openings 15 and 16 on the ventral side of the transition piece flow sleeve 4, and the cooling fluid flows directly into the openings 15 and 16 on the ventral side of the transition piece flow sleeve 4.
7, the fluid flows through gaps between the transition pipe flow sleeves arranged in the circumferential direction. It flows into the openings 15 and 16 on the back side of the transition piece flow sleeve 4 after passing through the gaps between the transition piece flow sleeves 4 and wrapping around the outer periphery. Fifth
The figure shows the flow of cooling fluid from the compressor to the transition piece flow sleeve 4 and a conceptual diagram of the transition piece flow sleeve 4,
(A) is a cross-sectional side view, (B) is a perspective view, and (c) is a plan view.

The turbine side portions on both sides of the transition piece flow sleeve 4 have a notched structure. Since the transition piece 3 is cooled in this notch by the flow of cooling fluid from the compressor, convection cooling is performed. Furthermore, in this embodiment, the gap between the circumferential transition piece flow sleeves 4, which serves as a flow path through which the cooling fluid from the compressor flows to the outer periphery of the transition piece flow sleeve 4, can be widened. The pressure difference between the outer peripheral part and the inner peripheral part of the transition tube flow sleeve 4 in the combustor chamber can be reduced by iJz, and the pressure loss as a combustor can be minimized accordingly.

Figure 6 shows a comparison of pressure loss in the combustor liner between the case where the transition piece flow sleeve 4 is installed around the entire circumference of the transition piece 3 and the case where both sides of the transition piece flow sleeve 4 are cut out. According to the diagram (Figure 6).

It is understood that the double-side notch structure can reduce the pressure loss from the vehicle compartment to the transition piece flow sleeve 4 by half compared to the full circumferential structure.

〔Effect of the invention〕

According to the present invention, it is possible to minimize the pressure loss of the cooling fluid in a gas turbine whose temperature has become high in order to improve efficiency, and to maintain the metal temperature of the transition piece and combustor liner within an allowable value. This has an excellent practical effect of improving the efficiency of the gas turbine.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a combustor chamber in one embodiment of the present invention. FIG. 2 is a chart showing changes in the cross-sectional area of the transition piece, and FIG. 3 is a chart showing changes in the heat transfer coefficient of the transition piece. Figure 4 is a partial sectional view showing details around the transition piece, Figure 5 is a conceptual diagram of the transition piece,
FIG. 6 is a chart showing the pressure loss of the flow sleeve structure inside the combustor. 1... Combustor liner, 2... Combustor liner flow sleeve, 3... Transition piece, 4... Transition piece flow sleeve,
5... Combustor outer cylinder cover, 6... Combustor outer cylinder, 7.
...Discharge casing, 8...Combustor casing, 9.
... Turbine casing, 10 ... Fuel nozzle, 11
...Spark plug, 12...Inner barrel, 13...
Compressor, 14... Turbine, 15, 16.17...
Tail tube flow sleeve opening.

Claims (1)

[Claims] 1. In a gas turbine combustor having a structure in which a flow sleeve is installed facing and spaced apart from the outer circumferential side of the transition piece in order to cool the transition piece that connects the combustor liner and the turbine section, (a) Nozzle holes are arranged in the flow sleeve in a portion facing the dorsal side and the ventral side in the downstream area, and the cooling fluid jetted from the nozzle holes collides with the wall surface of the transition tube to perform impingement cooling. At the same time, the collided cold section fluid flows downstream to perform convection cooling, and (b) the flow sleeves at the portions facing both downstream sides of the transition piece are cut out to perform convection cooling by the cooling fluid. The structure is such that
(c) A gas turbine combustor characterized in that a portion of the flow sleeve other than the above is structured to allow cooling fluid to flow between the flow sleeve and the transition piece.