JPH0559965A - Cooling device for gas turbine blade - Google Patents

Abstract

PURPOSE:To prevent excessive supply of air by controlling a rate of cooling air for turbine blades properly gased on a signal from a measurement means when neither water nor steam is injected. CONSTITUTION:A flow signal from a flow rate detector 9 for water or steam is converted into a control valve opening signal by means of a programmer controller 10 for adjusting an opening of a cooling air control valve 11 based on an injection amount. The flow rate of the cooling air is made to be zero when injection is not carried out. It is thus possible to supply a proper rate of cooling air, and keep the temperature of turbine blade metal constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine rotor blade cooling device, and more particularly to controlling the amount of cooling air.

[0002]

2. Description of the Related Art FIG. 2 is a system diagram of conventional gas turbine blade cooling air.

The high-pressure air compressed by the air compressor 1 burns the fuel flowing into the combustor 2 through the fuel control valve 3,
It becomes hot gas and expands in the turbine 4. Turbine 4
Drives the air compressor 1 and drives the generator 5 as an output. A part of the compressed air is branched, introduced into the turbine 4 through the air cooler 6 and the filter 7, and flows into the hollow turbine moving blade to cool the moving blade. Also,
Water or steam is injected into the combustion region of the combustor 2 via the control valve 8 to lower the combustion temperature and reduce NO _X which is a pollution.

[0004]

1) When steam is mixed in the combustion gas, the heat transfer coefficient on the gas side increases. Therefore, when water or steam is injected into the combustor, the metal temperature of the turbine blades rises as compared with the case where no injection is performed.

2) In the prior art, no control device is installed in the cooling air system. In addition, the design is intended for water or steam injection, which has the most severe blade temperature conditions. Therefore, when the injection is not performed, excessive cooling air bypasses the combustor from the air compressor and flows into the turbine, which deteriorates the performance of the gas turbine.

[0006]

In order to solve the above-mentioned conventional problems, the present invention provides a gas turbine apparatus comprising a compressor, a combustor and a turbine, in which water or steam is supplied to the combustor. Means, bleeding air means for bleeding air from the compressor and sending it to the turbine blades, measurement means provided in the supply means for measuring the flow rate of water or steam supplied, and receiving signals from the measurement means, Comprising: arithmetic means for determining the amount of air supplied to the turbine blade; and flow rate control means provided in the extraction means for adjusting the amount of air supplied to the turbine blade according to a signal from the arithmetic means. The present invention proposes a gas turbine blade cooling device characterized by the following.

[0007]

When water or steam is injected, the injection flow rate is detected by the flow rate measuring means, and the calculating means determines the cooling air flow rate to the turbine blade based on the detection signal and adjusts the flow rate control means. When the water or steam is not injected, the flow rate control means is adjusted so that the cooling air flow rate becomes zero.

[0008]

FIG. 1 is a system diagram of a turbine blade cooling device according to an embodiment of the present invention. A flow rate signal from the flow rate detector 9 for water or steam is converted into a control valve opening degree signal by a programmable controller (calculation means) 10, and the opening degree of the cooling air flow rate control valve 11 is adjusted according to the injection amount. The cooling air flow rate control valve 11 is usually provided with a bypass valve 12.
Generally, current or voltage is used for the flow rate signal, and air pressure is used for the control valve opening signal.

[0009]

According to the present invention, when water or steam is not injected, the turbine blade cooling air that was conventionally supplied excessively is controlled to an appropriate amount, and the performance of the gas turbine is improved accordingly. Further, at the time of injection, cooling air corresponding to the injection amount is supplied, the turbine blade metal temperature is always kept substantially constant, and the life is extended.

[Brief description of drawings]

FIG. 1 is a system diagram of a gas turbine blade cooling device according to an embodiment of the present invention.

FIG. 2 is a system diagram showing an example of a conventional gas turbine rotor blade cooling device.

[Explanation of symbols]

 2 Combustor 4 Turbine 6 Air Cooler 7 Filter 9 Water or Steam Flow Rate Detector 10 Programmable Controller (Computing Unit) 11 Cooling Air Flow Rate Control Valve 12 Bypass Valve

Claims (1)

[Claims] 1. A gas turbine apparatus comprising a compressor, a combustor and a turbine, a supply means for supplying water or steam to the combustor, and a bleed air for bleeding air from the compressor and sending it to turbine blades. Means, measuring means for measuring the flow rate of the supplied water or water vapor provided in the supply means, computing means for receiving a signal from the measuring means and determining the amount of air supplied to the turbine blade, and the drawing-out means. A gas turbine blade cooling device, comprising: a gas control means, which is provided in the air means and adjusts an air supply amount to the turbine blade according to a signal from the arithmetic means.