JP2977340B2 - gas turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine applied to thermal power generation and the like.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are explanatory views of a conventional gas turbine used for thermal power generation. In the figure,
The compressed air discharged from the axial air compressor 1 flows into the turbine through the combustor 2, but a part of the compressed air is branched and guided to the outside, and flows into the turbine through the filter 4 and the air cooler 5. Then, the turbine disk 6 and the hollow rotor blades 7 are cooled. Usually, the temperature of the compressed air flowing into the turbine via the combustor 2 is 350 to 400 ° C., and the temperature of the cooling air flowing into the turbine via the air cooler 5 is about 100 to 250 ° C. Water is used for cooling the cooling air, and the water flows into the air cooler 5 through the shutoff valve 8. When the water quality is bad and the tube nest of the air cooler 5 is corroded, air is used, and the air is sent to the air cooler 5 through a filter via a damper by a fan.

[0003]

In the above conventional gas turbine, the amount of axial elongation differs between the rotating body and the stationary body of the gas turbine due to differences in metal temperature, heat capacity, and thermal expansion coefficient of the material. . In particular, when the difference in the amount of expansion increases when the load is unsteadily changed, such as when the gas turbine is started or when the load increases, a trouble occurs in which the rotating body and the stationary body come into contact with each other. Is measured and managed, and a gap is provided in the axial direction between the rotating body and the stationary body, which is expected to be in contact, enough to avoid contact in advance. However, this gap contributes to increase the cost by lengthening the rotor of the gas turbine, and may increase the span of the rotor to cause vibration.

[0004]

SUMMARY OF THE INVENTION The gas turbine according to the present invention has an object to solve the above-described problems, and outputs a signal corresponding to a difference in the amount of heat between a rotating body and a stationary body in the axial direction due to heat. And turbine output according to the output signal
Means for controlling the temperature of the gas for cooling the disk and the hollow rotor blades .

[0005]

That is, in the gas turbine according to the present invention,
According to the signal output in accordance with the difference in the amount of elongation in the axial direction due to heat between the rotating body and the stationary body, the turbine disk and
The temperature of the gas that cools the airfoil is controlled, and the inside of the gas turbine is cooled according to the difference in the amount of axial elongation between the rotating body and the stationary body. The peak of the difference in the amount of elongation between the rotating body and the stationary body when the load is unsteady is reduced. Thus, the gap for avoiding contact between the rotating body and the stationary body can be reduced to shorten the rotor.

[0006]

1 to 3 are explanatory views of a gas turbine according to one embodiment of the present invention. In the figure, the gas turbine according to the present embodiment is used for thermal power generation, and the compressed air discharged from the axial flow air compressor 1 flows into the turbine via the combustor 2 as shown in FIG. A part of the compressed air is branched and guided to the outside, flows into the turbine via the filter 4 and the air cooler 5, and cools the turbine disk 6 and the hollow blade 7. Usually, the temperature of the compressed air flowing into the turbine via the combustor 2 is 350 to 400 ° C., and the air cooler 5
The temperature of the cooling air flowing into the turbine through
It is about 50 ° C. Water is used for cooling in the air cooler 5 , and the water flows into the air cooler 5 through the shutoff valve 8. In addition, the water quality is poor, and the tube nest of the air cooler 5 corrodes.
In this case , air is used, and as shown in FIG.
The air is blown to the air cooler 5 through the damper 13 by the fan 12.

The amount of elongation in the axial direction differs between a rotating body and a stationary body of a gas turbine due to differences in metal temperature, heat capacity, and thermal expansion coefficient of the material. In particular, when the difference in the amount of elongation increases when the load is unsteady, such as when starting the gas turbine or when the load rises, a problem may occur in which the rotating body and the stationary body come into contact with each other. A non-contact eddy current type displacement sensor 9 utilizing an electrical characteristic whose displacement is proportional to an output voltage so as to be managed is installed at a rotor shaft end of a gas turbine. The change in the gap S due to the difference in the amount of elongation detected by the displacement sensor 9 is converted into an output signal by the displacement converter 10, transmitted to the control room, and input to the differential elongation adjuster 14. The expansion difference controller 14 compares the set value with the value detected by the displacement sensor 9 and sends air having a pressure corresponding to the difference in the expansion amount to the water flow control valve 15. As this air source, a constant-pressure gas turbine control air is used. When air is used as the cooling medium of the cooling air, the air sent from the differential expansion controller 14 is sent to the fan 12 and the damper 13 for controlling the air volume. In addition,
When the air volume of the fan 12 is controlled by the blade angle control of the fan 12, a signal corresponding to the air sent from the differential expansion controller 14 is transmitted to the variable pitch servomotor of the fan 12 and by the speed control of the fan 12. If
It is sent to the rotation speed control device of the fan 12 respectively.

The difference in elongation between the rotating body and the stationary body of the gas turbine depends on the temperature of the cooling air. That is, when the flow rate of the cooling medium of the cooling air is small, the rotor expands well, and when the flow rate of the cooling medium is large, the expansion amount is small, but the flow rate of the water flow control valve 15 or the damper 13 Is controlled, the amount of water and the amount of air flowing into the air cooler 5 are controlled, and the temperature of the cooling air flowing into the turbine is adjusted. FIG. 3 shows the difference in the amount of elongation between the rotating body and the stationary body in the axial direction after the start of the gas turbine. Significantly decreased. Therefore, in the present gas turbine, the trouble of the rotating body coming into contact with the stationary body is prevented, the length of the rotor of the gas turbine is shortened, the cost is reduced, and the vibration resistance of the rotor is improved.

[0009]

The gas turbine according to the present invention is constructed as described above, and the rotor can be shortened, so that the cost is reduced and the vibration resistance of the rotor is improved.

[Brief description of the drawings]

FIG. 1 is a control system diagram of a gas turbine according to one embodiment of the present invention.

FIG. 2 is a detailed view of a main part thereof.

FIG. 3 is an explanatory diagram of the operation.

FIG. 4 is a control system diagram of a conventional gas turbine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Axial air compressor 5 Air cooler 9 Displacement sensor 10 Displacement converter 13 Damper 14 Differential expansion regulator 15 Flow control valve

Claims (1)

(57) [Claims] 1. A means for outputting a signal corresponding to a difference in the amount of elongation in the axial direction due to heat between a rotating body and a stationary body, and gas for cooling a turbine disk and a hollow rotor blade in accordance with the output signal. Means for controlling the temperature of the gas turbine.