RU2557878C1 - Anti-icing system of gas turbine engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: anti-icing system of the gas turbine engine contains the heat exchanger installed in air-gas channel of the engine upstream the engine compressor. The air tapped downstream the last stage of the compressor is supplied through the heat exchanger into the turbine cooling system. The pressure ratio of the compressor is greater than 25, and flow rate of the air tapped from the compressor amounts δ = (0.05÷0.07)·(1+m), where δ - a share of the air tapped from the compressor; m - engine bypass ratio. Between the heat exchanger and the compressor the protection grid is installed.

EFFECT: anti-icing system protects the engine from penetration of ice and other foreign subjects, improves traction and input-output characteristics of the engine.

4 cl, 2 dwg

Description

The invention relates to aircraft engine manufacturing.

The anti-icing system (POS) of a gas turbine engine (GTE) is designed to minimize the impact of meteorological conditions causing engine icing on safety and regularity of flights.

Known anti-icing system for a gas turbine engine, containing a heat exchanger installed in the engine duct, through which air taken after the last stage of the compressor is supplied to the turbine cooling system, the heat exchanger is installed in front of the compressor (patent US 2812897 A, IPC F02C 7/047, 1957 )

Known cooling systems for gas turbines in which air is taken from the engine compressor (Theory of aircraft engines. Edited by P.K. Kazanjan. - M .: Mechanical Engineering, 1983, p. 189, Fig. 1.11). Their effectiveness with degrees of increase in air pressure in the compressor over 25 decreases due to an increase in the temperature of the cooling air (ibid., P. 196, Fig. 11.10).

A known system for protecting a gas turbine engine from foreign objects, which uses a protective mesh installed at the entrance to the engine compressor. The system is installed on a Su-27 aircraft. The disadvantage of the system is the high probability of icing of the grid, which makes its use unsafe.

The aim of the invention is to increase the safety of operation of gas turbine engines, their gas-dynamic efficiency.

This goal is achieved by the fact that in the flow part of the turbine engine before entering the compressor, the pressure increase of which is more than 25, a heat exchanger is installed through which air, taken after the last stage of the compressor, is supplied to the turbine cooling system. To exclude the possibility of negative temperatures at the engine inlet at outdoor temperatures from plus 5 to minus 25 ° C, at which icing is possible, the air flow taken from the compressor is δ = (0.05 ÷ 0.08) · (1 + m), where δ is the fraction of air taken; m is the bypass ratio of a gas turbine engine.

The essence of the invention lies in the fact that the thermal energy of the air taken from the high-pressure compressor, in the quantities indicated above, is used (sufficient) to protect the engine from icing, and the coolant entering the air engine is used to additionally cool the turbine.

Additionally:

a protective net is installed between the heat exchanger and the compressor inlet to protect the engine from foreign objects;

To regulate (depending on the outdoor temperature) the air flow taken from the compressor, an air flow regulator is installed in its supply line.

In FIG. 1 shows a double-circuit gas turbine engine equipped with a PIC;

in FIG. Figure 2 shows the gas temperatures in front of the turbine and the heating of the air in the heat exchanger for gas turbine engines with various degrees of pressure increase in the compressor.

In the channel of the double-circuit gas turbine engine (Fig. 1), a heat exchanger 1 is installed at the compressor inlet. Air passes through the heat exchanger 1, taken after the last stage of the compressor, which is supplied to the turbine cooling system. An air flow regulator 2 is installed in the air supply line from the compressor to the heat exchanger. A protective net 3 is installed between the heat exchanger 1 and the compressor inlet.

The work of the PIC is as follows. Air is compressed in the compressor, the degree of pressure increase of which is more than 25, is heated. Part of the air δ = (0.05 ÷ 0.08) · (1 + m), where m is the bypass ratio of the gas turbine engine, enters the heat exchanger 1. As a result of heat exchange, the air entering the compressor is heated to a temperature at which the engine icing up ( mesh) does not occur, and the air coming from the heat exchanger into the turbine cooling system is cooled. The value of the relative air flow δ varies in the range indicated above, depending on the temperature of the outdoor air using the controller 2.

At positive outside temperatures, there is no need to protect the engine (grid) from icing. In this case, the air flow regulator 2 is set to the minimum air flow δ, at which the required cooling of the turbine is provided.

In FIG. 2 presents the results of evaluating the effectiveness of PIC. The assessment was performed using the coefficients of air cooling intensity in the heat exchanger υ ₁ and blades in the turbine υ ₂ , which are: a) the ratio of the difference in air temperature behind the compressor and at the inlet of the turbine cooling system to the air temperature difference between the compressor output and the engine inlet; b) the ratio of the temperature difference between the gas and the turbine blade to the temperature difference between the gas temperature in front of the turbine and the air temperature at the inlet to the turbine cooling system (Theory of Aircraft Engines. Edited by P.K. Kazanjan. - M.: Mechanical Engineering, 1983, p. 193).

Initial data: temperature of the turbine blades T _l = 1100 K; intensity coefficient of air cooling in the heat exchanger υ ₁ = 0.5; the coefficient of intensity of cooling of the blades in the turbine υ ₂ = 0.6 ÷ 0.65; relative air flow δ = (0.05 ÷ 0.08) · (1 + m); the degree of pressure increase in the compressor π _to = 20 ÷ 40.

From FIG. Figure 2 shows that the use of PIC (for given coefficients of cooling intensity) provides air heating ΔТ _tep at the engine inlet, at which icing of the engine (mesh) does not occur (at outdoor temperatures, high minus 25 ° С, and π _к , large 25 , the air temperature at the engine inlet remains positive). It is also seen that the use of PIC allows you to increase the gas temperature in front of the turbine T _g * by more than 20% with respect to cooling, in which the air drawn from the compressor is supplied to the turbine directly (without a heat exchanger).

The use of POS can improve the safety of gas turbine engine operation by eliminating the ingress of ice into the engine, and with the net, other foreign objects.

The use of POS makes it possible to increase the efficiency of a gas turbine engine as a heat engine by increasing the gas temperature in front of the turbine to 2000 K and more as a result of cooling the turbine blades with cooler air.

The use of POS makes it possible to improve the traction and flow characteristics of a gas turbine engine at outdoor temperatures of less than minus 15 ° С due to the optimization of the engine control program (there is no need to use a reduced speed limiter, which reduces the physical speed of the turbocharger).

The greatest effect of the use of PIC (δ <0.16) is achieved on engines with bypass degrees less than unity.

Claims (4)

1. An anti-icing system for a gas turbine engine, comprising a heat exchanger installed in the engine flow section before entering the engine compressor, in which the air taken after the last stage of the compressor is supplied through the heat exchanger to the turbine cooling system, characterized in that the degree of pressure increase in the compressor is more than 25 , and the air flow taken from the compressor is δ = (0.05 ÷ 0.07) · (1 + m), where δ is the fraction of air taken from the compressor; m is the bypass ratio of the engine. 2. The anti-icing system of a gas turbine engine according to claim 1, characterized in that a protective mesh is installed between the heat exchanger and the compressor inlet. 3. The anti-icing system of a gas turbine engine according to claim 1, characterized in that an air flow regulator is installed in the air supply line. 4. The anti-icing system of a gas turbine engine according to claim 1, characterized in that the bypass ratio of the engine is less than one.

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