JPH03264703A - Gas turbine cooling moving blade - Google Patents

Abstract

PURPOSE:To enhance cooling efficiency and simplify manufacture of a cooling blade for a high temperature turbine of a return flow type where steam is used as a cooling medium by additionally disposing a separator for separating a supply port and a recovery port of the cooling medium on upstream and downstream sides respectively. CONSTITUTION:A steam cooling moving blade 30 of a gas turbine is constituted in a return flow type with the planted portion thereof arranged in a rotor. A steam supply port 32 and a steam recovery port 33 are disposed upstream and downstream of a blade bottom portion, respectively. A sealing projection 34 as a separator for separating supplied steam from recovered steam is provided in the bucket bottom portion. In the bucket 30, a passage B is disposed outside of another passage A inside the blade 30, and both ends of each channel passage A, B are separated by the sealing projection 34 for the use as the steam supply port 32 and the steam recovery port 33. Therefore, the blade 30 can be convectively cooled with the steam passing through the passages A, B, and further, the blade 30 can be easily manufactured by precision casting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a gas turbine cooling rotor blade that uses steam as a cooling medium for the cooling blade of a high-temperature turbine.

(Prior Art) Generally, a gas turbine used in a power generation plant is configured as shown in FIG. This gas turbine uses a compressor 1 to compress air taken in from an air suction passage 7 to high pressure, and guides this compressed air to a combustor 2. In the combustor 2, the flow rate is adjusted by the flow rate control device 6, and the fuel and compressed air supplied from the fuel supply path 8 are mixed and combusted. High-temperature, high-pressure combustion gas generated by combustion in the combustor 2 is sent to the turbine 3, where it performs work while expanding, and is then discharged to the outside through an exhaust flow path 9 and a chimney 5. Note that the rotating shaft of the turbine 3 is connected to a driven machine 4 such as a generator.
is connected to the load via a coupling (not shown).

It is known that in this type of gas turbine, increasing the turbine inlet temperature increases the thermal efficiency of the gas turbine. In order to increase the turbine inlet temperature, it is necessary that the turbine components be designed to withstand high temperature combustion gases. For this reason, a great deal of effort has been put into developing heat-resistant materials and cooling techniques. In addition to air cooling, liquid cooling, steam cooling, and combinations thereof have been devised for cooling turbine rotor blades, but only air-cooled blades are currently in practical use.

Here, a conventional return flow type air cooling blade is shown in FIG. This air cooling blade 10 supplies cooling air from the bottom and performs convection cooling by passing through the blade leading edge side flow path 11 and the trailing edge side flow path 12, and all the air used for cooling is in the mainstream of the passage. It is designed to be released into gas. This air cooling vane 10 does not take any consideration to the recovery of cooling air.

Incidentally, in recent years, as combined cycle power generation and cogeneration, which combine a gas turbine and a steam turbine, have been put into practical use due to their high efficiency, expectations are high for the development of steam-cooled gas turbines. Although steam has a higher specific heat than air and is an excellent cooling medium, research into its practical application has lagged until now, partly because it requires a lot of incidental equipment to generate steam.

However, the situation has completely changed with the advent of combined cycle power generation and cogeneration. This is because combined cycle power generation and cogeneration plants not only already have steam generation equipment, but also can make the power plant even more efficient by recovering the steam used for cooling. Figure 5 shows air cooling and steam cooling in combined cycle power generation (steam is recovered)
A comparison of power generation efficiency is shown below.

Among the steam-cooled rotor blades that have been proposed in the past, those with a steam recovery function are disclosed in, for example, U.S. Patent No. 3,443.790.
(1969), and this steam-cooled rotor blade is shown in FIG. This steam cooled rotor blade 2
0 is a porous blade having a chamber 22 in the tip part 21, and the steam introduced into the root part 23 passes through the pores 24, is guided to the chamber 22 of the tip part 21, and then returns to the pore 2.
5 and return to the route section 26 to be collected. Here, the steam cools the rotor blades 20 when passing through the pores 25.

(Problems to be Solved by the Invention) Problems with conventional steam-cooled rotor blades include poor cooling efficiency and manufacturing difficulties. first,
Regarding the poor cooling efficiency, firstly, the flow velocity in the chamber of the chip section is low, and the chip section cannot be sufficiently cooled. Second, convection cooling with only pores on the leading edge side of the blade cannot adequately cope with high temperatures.

Thirdly, convection cooling using perforated blades itself has low cooling performance, and the number of holes needs to be increased in order to cope with higher temperatures, but there is a limit to increasing the number of holes due to strength reasons.

Regarding manufacturing difficulties, the first problem is the supply of steam and
Advanced casting and processing techniques are required to connect the cut holes in the blades for recovery with the cooling holes. Second, manufacturing costs are high because many drill holes are required to install the rotor and blades in order to supply and recover steam. Thirdly, increasing the number of holes for strengthening cooling is limited by precision casting technology and processing technology.

Therefore, the present invention has been made in consideration of the above circumstances.
The purpose is to provide a gas turbine cooling rotor blade that has high cooling efficiency, allows steam recovery, and is easy to manufacture.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the gas turbine cooling rotor blade of the present invention employs a return flow method for gas turbine cooling using steam as a cooling medium for cooling blades of a high-temperature turbine. The rotor blade is characterized by being provided with a separator that separates the cooling medium supply port and recovery port into an upstream side and a downstream side of the blade.

(Function) In the present invention having the above configuration, the return flow type rotor blade can be easily manufactured by precision casting, so it is possible to easily manufacture one having steam supply and recovery functions, and furthermore, these functions allow steam cooling. It is also possible to achieve high temperatures and high efficiency through steam recovery, as well as high efficiency through steam recovery.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a first embodiment of a gas turbine cooling rotor blade according to the present invention. The steam-cooled rotor blades 30 of this gas turbine adopt a return flow method, and the implanted portion 31 is connected to the rotor 4.
0 (see Figure 3). The steam supply port 32 is provided on the upstream side of the blade bottom, and the steam recovery port 33 is provided on the downstream side of the blade bottom, and a seal as a separator is installed at the blade bottom to separate and cut off the supplied steam and the recovered steam. A projection 34 for use is provided.

This steam-cooled rotor blade 30 has a flow path B arranged outside the flow path A in the rotor blade, and sealing protrusions 34 at both ends of each flow path A and H.
It is separated and used as a steam supply port 32 and a steam recovery port 33. Here, when increasing the number of channels,
A similar function can be obtained by further arranging a channel C1, a channel D, etc. outside the channel B. Seal protrusion 3
4 can be provided directly on the rotor 40 side, but in consideration of workability, it is better to provide it on the rotor blade 30 side.

In this embodiment, steam was supplied from the upstream bottom and recovered at the downstream bottom, but the reverse is of course possible.

Further, a steam exhaust hole 35 is provided at the leading edge of the steam-cooled rotor blade 30.
A large number of holes are provided to effect convection cooling at the front edge, and a bottle fin 36 is provided at the rear edge to effect bottle fin cooling.

Next, the operation of this embodiment will be explained.

Cooling steam is supplied from the supply port 32 of the rotor blade 30, and this steam passes through channels A and B and is recovered from the recovery port 33. Therefore, in this embodiment, most of the rotor blades 30 are in the flow path A.
and the steam passing through channel B causes convection cooling. If turbulence promoters are provided in the flow paths A and B, the cooling effect will be further enhanced.

Further, as shown in FIGS. 1 and 2, blowout convection cooling is used at the leading edge, and bottle fin cooling is used at the trailing edge. Incidentally, since the leading edge has a particularly high heat transfer coefficient on the blade surface and requires enhanced cooling, we used blowout convection cooling with high cooling efficiency, and the trailing edge is thin due to the requirements for the fluid performance of the blade. Since it is difficult to form a flow path, bottle fin cooling is used. In addition, when a flow path can be formed to the trailing edge using a thick-walled blade, or when cooling the leading edge is not required, efficiency can be improved by collecting the entire amount of steam from the bottom instead of discarding it into the mainstream. It is better to aim for it.

According to this embodiment, both ends of the flow paths A and B are separated by the sealing protrusion 34 and used as the steam supply port 32 and the steam recovery port 33, so that the steam can be supplied and recovered. The structure is significantly simplified. In addition, these structures can be manufactured at once by precision casting, which greatly facilitates manufacturing.

FIG. 4 shows a second embodiment of a gas turbine cooling rotor blade according to the present invention, and the same parts as in the first embodiment will be described with the same reference numerals. In this embodiment, the blade bottom is separated by a separation protrusion 38 serving as a separator, and a steam supply port 32a and a steam recovery port 033a are arranged on both the front and rear surfaces of the blade bottom. Therefore, according to the gas turbine cooling rotor blade of this embodiment, the same effects as those of the first embodiment can be obtained. The other configurations and operations are the same as those of the first embodiment, so their explanation will be omitted.

〔Effect of the invention〕

As explained above, according to the gas turbine cooling rotor blade according to the present invention, the return flow method is adopted, and the steam supply and recovery ports are separated into the upstream and downstream sides of the blade to form the steam supply/recovery flow path. With this structure, it is possible to easily manufacture the device by precision casting, and it is also possible to achieve high temperature and high efficiency through steam cooling, and high efficiency through steam recovery.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a first embodiment of a gas turbine cooling rotor blade according to the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG.
Fig. 3 is a view taken in the direction of arrow ① in Fig. 1, Fig. 4 is a vertical cross-sectional view showing a second embodiment of the gas turbine cooling rotor blade according to the present invention, and Fig. 5 is a diagram showing the turbine inlet temperature and the airflow power generation. A graph showing the relationship with plant efficiency, Fig. 6 is a schematic diagram showing the general configuration of a gas turbine, Fig. 7 is a vertical cross-sectional view showing a conventional return flow type air-cooled rotor blade, and Fig. 8 is a conventional return flow type air-cooled rotor blade. FIG. 2 is a perspective view showing a steam-cooled rotor blade. 30...Steam cooling rotor blade, 32...Steam supply port, 3
3... Steam recovery port, 34... Seal protrusion (separator) 35... Steam exhaust hole, 36... Pin fin, 8... Separator protrusion (separator)

Claims (1)

[Claims] A return flow type gas turbine cooling rotor blade that uses steam as a cooling medium in the cooling blades of a high-temperature turbine, and includes a separator that separates the cooling medium supply port and recovery port into the upstream side and downstream side of the blade. A gas turbine cooling rotor blade characterized in that: