JPS60219401A - Reheat fuel blow-off blade of gas turbine - Google Patents

Abstract

PURPOSE:To promote the improvement of thermal efficiency, by providing reheat fuel blow-off holes in the trailing edge of a stationary blade and a moving blade to be unevenly distributed in a direction of height of the blade. CONSTITUTION:A gas turbine provides reheat fuel blow-off holes 2 in the trailing edge of a stationary blade and a moving blade to be unevenly distributed in a direction of height of the blade. Reheat fuel is fed into the blade from its inlet 1, and the fuel, after it is allowed to flow in a flow path in the blade so as to cool it, is blown off outside the blade from the blow-off holes 2 and brought into contact with working gas 5, performing combustion and reheating the working gas 5 by combustion heat of the fuel. In this way, thermal efficiency of the gas turbine can be improved by enabling the working gas to be reheated in an optional number of times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reheat cycle gas turbine in which reheat fuel is combusted within the turbine without using a reheater independent of the turbine to reheat working gas. This invention relates to thermal fuel blowing blades.

Conventional reheat cycle gas turbines will not run out unless an independent reheat combustor is provided between the high-pressure turbine and the low-pressure turbine. For this reason, the wind pipe that connects the turbine and the reheat combustor must have a structure that can withstand high temperatures and pressures, and must be arranged to minimize pressure loss. This makes cooling the liner significantly more difficult. Therefore, a reheat cycle gas turbine has to have an extremely complicated structure, and it is virtually impossible for a conventional reheat turbine to perform reheating more than once.

The present invention provides a turbine that can perform reheating an arbitrary number of times without providing a high-temperature, high-pressure gas wind pipe and a reheating combustor that have a complicated structure, and can significantly improve the thermal efficiency and specific output of the gas turbine. The purpose is to obtain an internal reheating device.

The structure and function of this invention will be explained based on the drawings as follows.

In Figures 1 and 2 (cross-sectional views of the blades along line A in Figure 1), high-temperature, high-pressure working gas expands while passing through the blade rows in the turbine from G to J, and its temperature increases. goes down. The combustible gas necessary to reheat the working gas whose temperature has dropped is fed into the blade from the blade entrance, passes through the flow passage 3 provided in the blade, and cools the blade at the same time. After being heated so that it is easily combusted, it is blown out to the blade rows through the blow-off holes provided at the trailing edge of the tail. The blown out flammable gas is a working gas whose temperature is higher than the spontaneous ignition temperature of the combustible gas.
Touch and burn. Since the blow-off holes at the trailing edge of the blade are arranged to be distributed non-uniformly in the height direction of the blade, the amount of reheating fuel gas blown out can be varied in the blade height direction. Therefore, the working fluid can be reheated so as to change the radial temperature distribution of the turbine as required by design.

FIG. 3 shows an example of an embodiment in which the blow-off holes are arranged on the trailing edge of the blade and the blow-off holes are not provided on the inner diameter side near the rotating shaft of the turbine. This figure is a longitudinal cross-sectional view of the blade shown in FIG. 1 along the line ■-■. The flammable gas enters from the inlet of the blade and flows through the flow path 3 to the trailing edge.In order to improve the cooling of the trailing edge of the blade, the combustible gas flows from the inner diameter side toward the outer diameter side in the last flow path A. It is provided so that it flows, and the blowout hole is provided only on the outer diameter side portion of this last flow path B. This structure allows reheating gas to be blown out only from the outer diameter side in the height direction of the blade without impairing the cooling effect of the trailing edge of the blade.

Figures q, 5 and 5 are external views of the trailing edge of the wing, respectively.

FIG. 1 shows an embodiment in which the width of the air outlet holes is varied in the blade height direction and continuous air outlet holes are provided in the blade height direction. Since the blowholes are continuous, the core can be easily handled when manufacturing the blades by precision casting.

FIG. 5 shows embodiment a in which the width of the air outlet holes is constant and the air outlet holes are provided discontinuously in the blade height direction. Since each blowout hole is independent, it is easy to fill the blowholes in order to adjust the blowout amount after manufacturing the blade.

FIG. 6 shows an embodiment in which the width of the air outlet holes is varied and the air outlet holes are discontinuous in the blade height direction. According to this method, it is possible to arbitrarily create the distribution of the amount of flammable gas blown out without changing the pitch of the blowing holes.

When flammable gas is blown out from the blade configured as described above, the area of the blowout hole at the trailing edge of the blade increases. - Since the pitch is unevenly distributed in the height direction of the blade, the required flow rate of combustible gas must be flowed in accordance with the pressure distribution of the working gas in the radial direction (in the height direction of the blade) behind the blade row. I can do it.

In particular, when the working gas j flowing out from the blade row has a velocity component in the circumferential direction of the turbine (the pitch direction of the blade row), that is, when it becomes a swirling flow, the gas behind the blade row has a velocity component equal to the density of the gas and the square of the swirling speed. is subjected to a centrifugal force proportional to the product of Normally, a pressure distribution is generated in the scum behind the blade row that increases from the inner diameter side toward the outer diameter side to balance the centrifugal force of 4tt1. When flammable gas is blown out, its combustion creates a localized high-temperature area in the gas behind the blade row, and the density of this area becomes low. Therefore, the centrifugal force acting on this high-temperature portion is smaller as the density is lower, and there is a difference from the centrifugal force acting on gases other than the high-temperature portion. As a result, 7
The gas in the high-temperature part due to combustion receives a force directed toward the inner diameter side according to the difference in centrifugal force, and the high-temperature gas flows toward the inner diameter side of the turbine. Because of this effect, if the blow-off holes for flammable gas are provided uniformly in the blade height direction, there is a risk that the flame will come into contact with the inner diameter side wall surface of the annular waste flow path at the rear of the blade row and burn out the wall surface. Therefore, by providing the blow-off holes offset toward the outer diameter side and distributing the blow-off holes in the blade height direction as in the embodiment described above, burnout of the inner wall surface of the gas flow path can be prevented and the difference in centrifugal force can be prevented. By using the inward flow generated by this, it is possible to create a desired temperature distribution along the radial direction in the flow behind the row of reheating fuel blowing blades.

As explained above, this invention has a simple structure in which the blow-off holes of the turbine blade for blowing out combustible gas for reheating are unevenly distributed in the height direction of the blade. In the annular gas flow path between the rotor blades or between the rotor blade and the next stage nozzle blade, the required temperature distribution can be changed in the radial direction without overheating the inner diameter side wall surface of the flow path. The working gas can be reheated.

[Brief explanation of drawings]

FIG. 1 is an external view of a reheating fuel blowing blade of a gas turbine constructed according to the present invention, FIGS. 2 and 3 are a cross-sectional view and a vertical cross-sectional view of FIG. 1, respectively, and FIGS. FIG. 1 is an outline view of an embodiment of a trailing edge blow-off hole constructed according to the present invention. / indicates the reheating fuel inlet, λ indicates the fuel gas blowout hole provided at the trailing edge, 3 indicates the fuel gas flow path that also serves as blade cooling, and j indicates the direction of the flow of working gas through the blade row. Arrow B indicates the fuel gas flow path in front of the bottom of the trailing edge blowout hole. Figure 1 Figure 213d Figure 3 Figure 41 Figure 5 Closed 61

Claims (1)

[Scope of Claims] l In a gas turbine capable of reheating by burning reheating fuel within the turbine without guiding working gas to a reheater outside the turbine, a stationary blade that blows out reheating fuel. and a reheating fuel blowing blade 2 characterized in that blowing holes are provided on the trailing edge of the rotor blade and blowing holes are distributed non-uniformly in the blade height direction. Claim 1: No blowing portion is provided on the inner diameter side.
Reheating fuel blowing blade 3 according to Claim 2 Reheating fuel blowing blade according to Claim 2, which has a blowing hole whose width is changed in the blade height direction and which is continuous in the blade height direction Blade 4 A fuel blowing blade 5 for reheating according to claim 2, which has a constant width of the blowing hole in the blade height direction and has blowing holes that are discontinuous in the blade height direction.
The reheating fuel blowing blade according to claim 2, wherein the width of the blowing hole is changed in the blade height direction and the blowing hole is discontinuous in the blade height direction.