RU2260134C1 - Gas-turbine engine starting method - Google Patents

Abstract

FIELD: aircraft engineering; aircraft engines.

SUBSTANCE: invention relates to methods of starting of gas-turbine engine. Proposed method includes delivery of working medium from auxiliary power plant to air turbine of starting device and following cranking of engine rotor by starting device. Used as working medium is gas from combustion chamber of auxiliary power plant, of mixture of gas and air from compressor of auxiliary power plant added to gas before its delivery to air turbine of starting device.

EFFECT: improved reliability of engine starting and reduced and time taken for starting without considerable changing of overall dimensions and weight of initial auxiliary power plant.

2 cl, 1 dwg

Description

The invention relates to the field of aircraft engine manufacturing, in particular to methods for starting a gas turbine engine.

A known method of starting a gas turbine engine (hereinafter - GTE), comprising supplying a working fluid from an auxiliary power plant (hereinafter - APU) to the air turbine of the starting device and the subsequent unwinding of the engine rotor with the starting device (1).

In the known method, an air starter is used as a starting device, mechanically connected to the shaft of the rotor of the engine. The starting device spins the engine rotor until the moment when the turbine begins to develop power sufficient to independently spin the engine rotor with a given acceleration, after which it turns off.

The main disadvantage of this method is to reduce the level of power supplied to the rotor of the engine due to the low level of energy efficiency of the APU, which leads to an increase in the start time of the engine and a decrease in its reliability. However, to ensure the required characteristics of the launch of a gas turbine engine, it is necessary to increase the power of the APU, while increasing its dimensions, weight and cost.

The problem to which the claimed invention is directed, is to increase the reliability of starting the engine and reducing the time it starts without significant changes in dimensions and weight of the original APU.

The problem is solved in that in the method of starting a gas turbine engine, which includes supplying a working fluid from the APU to the air turbine of the starting device and subsequent spinning of the engine rotor by the starting device, gas from the combustion chamber of the APU is used as the working fluid, while gas is supplied to the gas from the combustion chamber of the APU before feeding it can be mixed into the air turbine of the starting device from the APU compressor.

An increase in the temperature of the working fluid supplied to the air turbine significantly increases its specific power. This increases the level of power supplied to the rotor of the engine. The use of hot gas from the combustion chamber of the APU as a heated working fluid makes it possible to more fully use the potential capabilities of the APU itself. In this case, there is no need to change the design of the APU by introducing any elements of the heating of the working fluid.

In some cases, when a large power of the APU is not required, for example, at low ambient temperatures, in order to increase the resource and reliability of the structural elements of the APU, it is advisable to mix air from the APU compressor to the hot gas from the combustion chamber, while supplying a working fluid to the launch turbine’s air turbine lower temperature.

The proposed method is illustrated in the drawing, which shows a diagram of the launch system of a gas turbine engine.

The diagram shows the APU 1 with a compressor 2 and a combustion chamber 3 and an air turbine 4 of the starting device, the shaft of which is mechanically connected to the rotor shaft of the engine 5. The turbine 4 is connected by a pipe 6 to the compressor 2 of the APU 1 and the pipeline 7 with the internal cavity of the combustion chamber 3. Mixing air to gas is carried out in the mixer 8.

The method is as follows.

To increase the power transmitted to the rotor of the engine 5 from the starting device of the engine starting system, an APU 1 is turned on and hot gas is directed from the internal cavity of the combustion chamber 3 through the internal cavity of the mixer 8 through a pipe 9 to the air turbine 4 of the starting device.

In those cases when the increased power of the starting device is not required, compressed air is supplied to the mixer 8 from the compressor 2 of the APU 1, which is mixed in it with the hot gas supplied from the combustion chamber 3. Next, the mixture of gas with air through the pipeline 9 enters the air turbine 4 of the starting device. In this case, the selection of hot gas from the combustion chamber 3 is reduced compared with the same selection in the case of supplying to the starting device only gas. A decrease in gas extraction from the combustion chamber leads to a decrease in the operating temperature in front of the APU 1 turbine, which generally reduces the heat intensity of the APU.

The invention allows without significant changes in the dimensions and weight of the original APU to increase the reliability of engine start-up, as well as reduce its time.

Sources of information

1. B.M. Katz, E.S. Zharov, V.K. Vinokurov. Starting systems for aircraft gas turbine engines, - M.: Mechanical Engineering, 1976, p. 7-9.

Claims (2)

1. A method of starting a gas turbine engine, comprising supplying a working fluid from the auxiliary power unit to the air turbine of the starting device and subsequent spinning of the engine rotor by the starting device, characterized in that gas is used as the working medium from the combustion chamber of the auxiliary power unit. 2. The method according to claim 1, characterized in that the air from the auxiliary power compressor is mixed with gas from the combustion chamber of the auxiliary power unit before it is fed to the air turbine of the starting device.