JPH01125526A - Cooling air introducing device for gas turbine - Google Patents

Abstract

PURPOSE:To supply stably cooling air without pressure losses by constituting a cooling air flow path for introducing cooling air into a center hole in a turbine rotor from a plurality of slant introducing holes, a rotary cavity flow path and a plurality of inducer flow path rows disposed sequentially from the radial outside. CONSTITUTION:A distance piece 1 interconnecting a compressor rotor 10 and turbine rotor 8 is provided on the radial inside in the central portion with a disk 2 to which an inducer 12 is bolt fixed 4. The inducer 12 is provided with groove-like inducer flow paths 3 radially directed to the center of rotor. The radial outside and inside of the flow path 3 are respectively connected to a plurality of circular skew introducing holes 11 provided in the distance piece 1 and the center hole 5 of rotor. The inner peripheral side outlets of a plurality of said holes 11 are connected to a rotary cavity flow path 13 extending circumferentially and the inner peripheral side of the flow pat 13 is connected to the same number of inducer flow paths 3 as the introducing circular holes 11.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cooling air introduction device for a gas turbine, and particularly to a cooling air introduction device for a gas turbine suitable for supplying cooling air from the outside of the gas turbine into the rotor. Regarding the introduction device.

[Conventional technology]

A conventional cooling air introduction device for a gas turbine is described, for example, in Japanese Patent Application No. 56-62678.

A nozzle is placed at the front of a curved flow path (connected to the rotor center hole) that is directly attached to the turbine rotor, and the cooling air accelerated by the nozzle is diverted through the curved flow path to flow through the rotor center hole. is leading to

With this device, the swirling speed of the cooling air entering the rotor center hole can be controlled to be low, and the temperature of the cooling air can also be lowered.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology is mainly aimed at a system that directly guides cooling air from the compressor outlet into the rotor.

Therefore, when cooling air is extracted from the compressor, cooled in an intercooler installed separately from the gas turbine body, and then returned to the inside of the gas turbine rotor, or when there is no space to install a nozzle in front of a curved flow path, cannot be applied as is.

An object of the present invention is to provide a cooling air introduction device for a gas turbine that can introduce cooling air to a rotor center hole without causing a large pressure loss.

[Means for solving problems]

The above purpose is to connect the cooling air flow path that leads cooling air to the center hole of the turbine rotor to the rotor center hole and the rotating cavity flow path, which is connected in the circumferential direction to multiple diagonal circular introduction holes in order from the outside in the radial direction. This is achieved by constructing multiple rows of inducer channels.

Further, it is preferable that the number of the plurality of oblique circular introduction holes and the number of inducer channels be the same.

Furthermore, it is preferable to set the radial length of the rotary cavity flow path so that the inlet angle of the inducer flow path and the flow angle of the cooling air closely match.

[Effect]

Among the cooling air flow paths up to the rotor center hole, the circular introduction hole is
The introduction hole is opened circumferentially so that the swirling speed of the cooling air at the outlet is smaller than the circumferential speed at that radial position. This makes it possible to reduce the pressure drop of the cooling air in the 1-turn cavity flow path, making it easier to guide the cooling air into the 6-turn cavity flow path.Since the 6-turn cavity flow path is connected in the 5 circumferential direction, multiple It has the function of making the cooling air coming out of the circular introduction hole uniform in the circumferential direction, and can prevent pressure pulsations within the inducer flow path. Since the inducer flow path is a flow path toward the center of the rotor, the cooling air entering the rotor center hole does not have an excessive swirling speed, and pressure loss can be reduced.

Furthermore, since the number of circular introduction holes and the number of inducer channels are the same, unevenness in flow rate and pressure activation in each inducer channel are reduced.

Furthermore, since the angular momentum of the cooling air is conserved in the rotating cavity flow path connected in one circumferential direction, the radial length of the rotating cavity flow path can be adjusted by adjusting the inlet angle of the inducer flow path and the cooling air outlet of the rotating cavity flow path. Set so that the air flow angle matches. Therefore, the pressure loss of the cooling air at the inducer inlet is reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In Fig. 1, 1 is a daystand piece, which connects the compressor rotor 10 and the turbine rotor 8, and has a disk 2 in its center extending radially inward. 12 is fixed with bolt 4. The inducer 12 is provided with a groove-shaped inducer flow path 3, and the radially outer side of the inducer 12 is connected to the circular introduction hole 11 provided in the day stand piece 1, and the radially inner side is connected to the rotor center hole 5. has been done. Although not shown, the cooling air 6 is guided from an intercooler to the rotor center hole 5 via an inducer 12.

The structure of the inducer 12 will be explained in more detail using FIG. 2. FIG. 2 is a partial sectional view taken along line AA in FIG. 1. A plurality of diagonal circular introduction holes 11 are provided on the outer circumferential side of the inducer 12, and the inner circumferential outlet of the circular introduction holes 11 continues to a rotating cavity flow path 13 connected in the circumferential direction. The same number of inducer channels 3 as the circular introduction holes 11 continue on the inner peripheral side of the rotating cavity channel 13 .

The inner peripheral side outlets of the plurality of rows of inducer channels 3 are all connected to the rotor center hole 5. In this embodiment, the inducer channels 3 are arranged radially toward the center of the rotor.

Next, the operation of the present invention will be explained.

Air cooled by the intercooler is guided to the outer circumferential side of the day stand piece 1 through piping. The cooling air 6 is supplied through an oblique circular introduction hole 1 provided on the outer circumferential side of the day stand piece 11.
Enter the rotating body from 1.

At this time, since the circular introduction hole 11 is inclined in the direction of rotation, the cooling air 6 can easily flow in, and there is little pressure loss at the inlet. The cooling air 6 exiting the circular introduction hole 11 flows into the rotary cavity flow path 13. The flow inside the rotating cavity 13 will be explained using FIG. 3.

Figure 3 shows the velocity triangle at the entrance and exit of the rotating cavity flow path.One rotation cavity entrance (radius r = r
In 1), the cooling air flows in the same direction as the inclination angle θ1 of the circular introduction hole 11 at a relative speed w1. The turning speed Vul corresponding to the absolute speed v1 is the circumferential speed u as shown in FIG.
It is smaller than i (=rx·ωω; angular velocity). The angular momentum of the cooling air is conserved in the rotating cavity, so when the exit radius is rZ, Vul Il rl=Vu! '0 for which rZ holds true
In this embodiment, the exit radius rz is determined so that the turning speed Vu2 at the exit of the rotating cavity satisfies Vu2='Vu1=r2ω=uz.

That is, rz=G=τf; Therefore, the rotation speed does not become excessive in the rotating cavity flow path 13, so the pressure drop is reduced, and the flow angle θ2 of the cooling air at the outlet of the rotating cavity is directed toward the center of the rotor.

The cooling air 6 then flows into the inducer flow path 3,
Since all of the inducer channels 3 are radially directed toward the center of the rotor, the flow angle of the cooling air and the inlet angle of the inducer channel 3 match, and the cooling air at the inlet of the inducer channel 3 is pressure loss is smaller. Furthermore, since the cooling air is kept in a uniform state in the circumferentially connected rotating cavity flow paths 13, deviations in the cooling air flow rate and pressure fluctuations in the multiple rows of inducer flow paths 3 are also reduced.

Since the inducer flow path 3 is directed towards the center of the rotor,
At the inducer outlet, the difference between the swirling speed of the cooling air and the circumferential speed of the rotor center hole 5 is small, and the pressure loss at the rotor center hole can also be suppressed to a small value. Furthermore, since the number of inducer flow paths 3 and the number of circular introduction holes 11 are the same, the pressure fluctuation at the inducer flow path inlet is further reduced.

In this embodiment, since the inducer flow path has a linear shape, it is easy to process the inducer flow path.

Furthermore, the inducer flow path only needs to have the inlet angle of the flow path coincident with the flow angle of the cooling air, and there is no need for the inducer flow path to have a particularly linear shape as in this embodiment.

Further, in this embodiment, the cooling air is introduced into the rotor from the stand piece between the compressor rotor and the turbine rotor, but the same effect can be obtained even if the cooling air is introduced after the turbine rotor.

Furthermore, it is desirable that the corners of the inlet of the inducer channel and the inlet of the circular introduction hole be rounded and rounded, as shown in FIG.

Furthermore, although this embodiment describes a case in which cooling air is introduced from an intercooler outside the system to the rotor center hole, it can also be introduced directly into the rotor center hole without bleeding air from the compressor to the outside of the system. Can be applied.

〔Effect of the invention〕

According to the present invention, the pressure loss at the inlet of each cooling air flow rate and the pressure loss at the rotor center hole can be reduced, so cooling air can be stably supplied to the gas turbine with little pressure loss. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along the line AA' in the figure, and is a diagram showing the velocity triangle of the cooling air at the inlet and outlet of the rotating cavity flow path. 3... Inducer flow path, 5... Rotor center hole, 6
...Cooling air flow, 8...Turbine rotor, 11
...Circular introduction hole, 13...Rotating cavity. Figure 1 Figure 2 Figure 3 ′;Koichi 1ko

Claims (1)

[Scope of Claims] 1. A cooling air introduction device for a gas turbine comprising a turbine rotor of a gas turbine and a cooling air passage that guides cooling air to a center hole of the turbine rotor, wherein the cooling air passage is arranged in a radial direction. A gas turbine comprising, in order from the outside, a plurality of oblique introduction holes, a rotating cavity flow path connected in the circumferential direction, and a plurality of rows of inducer flow paths connected to the center hole of the turbine rotor. cooling air introduction device. 2. Cooling air for a gas turbine according to claim 1, characterized in that the number of the introducing holes of the cooling air flow path and the number of the inducer flow paths connected to the center hole of the turbine rotor are the same. Introduction device. 3. In claim 1, the radial length of the rotary cavity flow path is set so that the inlet angle of the inducer flow path of the cooling air flow path and the flow angle of the cooling air substantially match. A cooling air introduction device for a gas turbine, characterized in that: