RU2637153C1 - Method of operation of three-circuit turbojet engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: compressed air from the adaptive fan is divided into three streams. The stream of the first circuit is fed to the gas generator, the exhaust gases from which are fed into the low pressure turbine, and from it through the mixer and the afterburner into the main jet nozzle. The stream of the second circuit is fed through the afterburner into the main jet nozzle. The stream of the third circuit is fed to the nozzle of the third circuit. The operation of the engine is controlled by switching from a three-circuit operation scheme to a two-circuit operation scheme and back, and also by changing the degree of the two-circuit engine by switching the direction of the compressed air streams by means of the distribution devices and engaging the afterburner. In the maximum and transient operation modes with engine forcing, the compressed air stream of the third circuit is fed directly from the third circuit channel through the afterburner into the main jet nozzle. Opening and closing of switchgears for connecting and disconnecting the channel of the third circuit is carried out according to the values of the reduced low pressure rotor speed.

EFFECT: increase of the maximum flight thrust of the turbojet engine in maximum and transient modes with engine forcing while maintaining fuel consumption parameters.

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Description

The invention relates to the field of aviation technology and can be used in control systems of an aircraft power plant equipped with a three-circuit turbojet engine with afterburner.

One of the requirements for power plants of transport and civil aviation is the efficiency of the engine in conditions of long flights while ensuring the required levels of flight thrust, taking into account restrictions on overall dimensions. One of the main directions of increasing the fuel efficiency of turbojet engines is to reduce specific fuel consumption by increasing the bypass ratio of engines. However, the implementation of high values of the bypass ratio in turbojet engines is limited by a significant increase in overall characteristics. Therefore, the most promising direction for improving turbojet engines is the creation of a multi-circuit engine with regulation of the bypass ratio depending on the mode of its operation.

A known method of operation of a three-circuit turbojet engine, which consists in the fact that the compressed air from the adaptive fan is divided into three streams, the flow of the primary circuit is supplied to the combustion chamber, the exhaust gases from which are fed to high and low pressure turbines and then to the main jet nozzle, flow the second circuit is mixed in the mixer with the flow of the primary circuit, fed to the combustion chamber and the main jet nozzle, the flow of the third circuit through the switchgear is fed to the nozzle of the third circuit, new and transient engine operation modes, control engine operation parameters and regulate engine operation by switching from a three-circuit operation scheme to a two-circuit operation scheme and vice versa, as well as by changing the degree of the bypass engine by switching the direction of compressed air flows by distribution devices (application WO 2011/038188).

In the known method of operation, the control of the third circuit with a separate input and a two-tier fan stage is carried out using adjustable fan guides that are independent for each tier. The air of the third circuit in the proposed scheme is directed into the flow path for a critical section of the main nozzle. The main disadvantage of the proposed scheme is the use of a separate entrance to the channel of the third circuit and a two-tier fan blade, which in modes with the third circuit turned off creates additional power take-off from the low-pressure rotor, reduces the efficiency of the engine and limits the possibility of using the third circuit in various modes of engine operation.

A known method of operation of a three-circuit turbojet engine with an afterburner, which consists in the fact that the compressed air from the adaptive fan is divided into three flows, the flow of the primary circuit is supplied to a gas generator, exhaust gases from which are fed to a low pressure turbine, and from it to the main jet nozzle, the flow of the second circuit is fed through the afterburner to the jet nozzle, the flow of the third circuit is fed to the nozzle of the third circuit, the main and transient modes of the engine are set, as the parameters of the engine To control the fuel consumption in time and the rotational speed of the gas generator rotor and low pressure rotor and regulate the operation of the engine by switching from a three-circuit operation scheme to a two-circuit operation scheme and vice versa, as well as by changing the degree of a two-circuit engine by switching the direction of compressed air flow to the switchgear and turning it on afterburner (patent US 4080785).

In the known method of operation using an adjustable mixer, the air flow in the channels of the second and third circuits is controlled to obtain the required engine characteristics. The disadvantage of this method is the use of the third circuit only at subsonic speeds, which does not allow to increase the efficiency of the engine in forced modes of operation.

There is also known a method of operating a three-circuit turbojet engine with an afterburner, which consists in the fact that the compressed air from the adaptive fan is divided into three streams, the primary circuit flow is fed to a gas generator, the exhaust gases from which are fed to a low pressure turbine, and from it through a mixer and afterburner the chamber into the main jet nozzle, the flow of the second loop is fed through the afterburner to the main jet nozzle, the flow of the third loop is fed into the nozzle of the third loop, the main and transition modes of operation are set You, as the engine operation parameters, control the braking temperature of the air flow at the engine inlet, the fuel consumption in time and the values of the turbine rotor speed and regulate the engine operation by switching from a three-circuit operation scheme to a two-circuit operation scheme and vice versa, as well as by changing the degree of the bypass engine by switching the direction of the compressed air flow by the switchgear and turning on the afterburner into the operation (patent US 9279388).

In the known method of operation, the problem of regulating the operation of the fan is solved in such a way as to ensure a constant flow of compressed air at the engine inlet when the engine thrust changes in different modes of operation. For this, control is carried out of such parameters characterizing the operation of the engine as the air flow at the engine inlet, the stability margin of the high-pressure compressor. These parameters cannot be measured in flight; they can be obtained by estimation using additional input data. The disadvantages of this method include the fact that there is no possibility of supplying a compressed air stream of the third circuit through the afterburner to the main jet nozzle, which significantly limits the possibility of increasing the efficiency of the engine.

The closest analogue of the invention is a method of operating a turbojet engine with an afterburner, which contains features that match the essential features of the described invention, namely: compressed air from an adaptive fan is divided into three streams, the flow of the primary circuit is supplied to a gas generator, the exhaust gases from which are fed into low pressure turbine, and from it through the mixer and afterburner to the main jet nozzle, the secondary circuit flow is fed through the mixer and afterburner to the main react main nozzle, the flow of the third circuit through the switchgear is fed either to the nozzle of the third circuit or through the afterburner to the main jet nozzle, the main and transient modes of engine operation are set, the braking temperature of the air flow at the engine inlet is controlled as engine operation parameters, in time and frequency of rotation of the rotor of the gas generator and the low-pressure rotor, and regulate the engine by switching from a three-circuit operation scheme to a two-circuit operation scheme and It is clear, as well as by changing the degree of the bypass of the engine by switching the direction of compressed air flows by the switchgear and turning on the afterburner, and in the small, take-off and maximum modes, as well as in transition modes without boosting the engine, it operates according to the double-circuit, and the flow of compressed the air of the third circuit is sent to the channel of the second circuit, and in cruising mode without boosting the engine, the flow of compressed air of the third circuit through the channel of the third circuit round served in the nozzle of the third circuit (patent US 4064692).

In the known method, the compressed air stream of the third circuit is used only for bypassing from the middle of the adaptive fan to the main jet nozzle without the ability to direct the air of the third circuit into the afterburner directly from the channel of the third circuit. Moreover, the use of the channel of the third circuit in the known method is limited to subsonic throttle modes of the engine and does not allow to expand the capabilities of the engine in the main and transition modes with boosting its operation, which significantly reduces the efficiency of the engine in these modes and does not allow to increase flight thrust at maximum modes with engine boost.

The technical result of the invention is to increase the maximum flight thrust at maximum and transient modes of operation with boosting the engine while maintaining fuel consumption.

This technical result is achieved due to the fact that when implementing the method of operation of a three-circuit turbojet engine with afterburner, which consists in the fact that the compressed air from the adaptive fan is divided into three streams, the flow of the primary circuit is supplied to a gas generator, the exhaust gases from which are fed to a low turbine pressure, and from it through the mixer and afterburner to the main jet nozzle, the flow of the second circuit is fed through the mixer and afterburner to the main jet nozzle, the flow of the third loop either a third circuit nozzle or through an afterburner into the main jet nozzle are fed through a switchgear, the main and transient engine operating modes are set, the braking temperature of the air flow at the engine inlet, the fuel consumption in time and the rotation speed are controlled as engine operation parameters the rotor of the gas generator and the rotor of low pressure and regulate the operation of the engine by switching from a three-circuit operation scheme to a two-circuit operation scheme and vice versa, as well as by changing the degree of engine contour by switching distributors of the direction of compressed air flow and turning on the afterburner, and in small, take-off and maximum modes, as well as in transition modes without boosting the engine, it operates according to a two-circuit scheme, and the compressed air flow of the third circuit is sent to the channel the second circuit, and in cruising operation without boosting the engine, the compressed air stream of the third circuit through the channel of the third circuit is fed into the nozzle of the third circuit pa

According to the invention, at maximum and transient modes of operation with boosting the engine, the third circuit compressed air flow is supplied directly from the third circuit channel through the afterburner to the main jet nozzle, and the opening and closing switchgears for connecting and disconnecting the third circuit channel are carried out according to the values of the reduced rotor speed low pressure.

The significance of the distinguishing features of the method of operation of a three-circuit turbojet engine with an afterburner is confirmed by the fact that only the totality of all actions and operations describing the invention allows to obtain the technical result of the invention - increasing the maximum flight thrust of a turbojet engine at maximum and transient conditions with boosting the engine while maintaining fuel consumption parameters .

An example implementation of a three-circuit turbojet engine with afterburner is illustrated by drawings, where

in FIG. 1 shows a general view of a three-circuit turbojet engine with a variable working process;

in FIG. 2 shows a diagram of the engine in dual-circuit mode;

in FIG. 3 shows a diagram of the engine in three-circuit mode with the flow of compressed air of the third circuit into the afterburner;

in FIG. 4 presents a diagram of the engine in three-circuit mode with the supply of a compressed air stream of the third circuit to the nozzle of the third circuit.

A three-circuit turbojet engine contains an adaptive two-stage fan 1, the output of the second stage 2 communicated by the channel of the first circuit 3 with a gas generator 4, consisting of a high pressure compressor 5, a main combustion chamber 6 and a high pressure turbine 7. A low pressure turbine 8 is connected in series to the output of the gas generator 4, the mixer 9, the afterburner 10 and the main jet nozzle 11.

Also, the adaptive fan 1 by the output of the second stage 2 through the channel of the second circuit 12 is connected in series with the mixer 9, the afterburner 10 and the main jet nozzle 11, and the output of the first stage 13 is communicated through the switchgear 14 with the channel of the third circuit 15 connected through the switchgear 16 to the jet nozzle of the third circuit 17, as well as to the mixer 9, the afterburner 10 and the main jet nozzle 11.

The adaptive fan 1 is driven by a low pressure turbine 8 using a low pressure rotor 18. The high pressure compressor 5 is driven by a high pressure turbine 7 using a high pressure rotor 19.

To control the operating parameters in the engine, a sensor 20 for braking the air flow at the engine inlet, a fuel consumption sensor 21, and rotational speed sensors 22 and 23 of the gas generator rotor and low pressure rotor, respectively, are installed. Sensors 20, 21, 22 and 23 are connected to a comparator 24 connected to a control unit 25.

The operation of a three-circuit turbojet engine is as follows. Compressed air from the adaptive two-stage fan 1 is divided into three streams, the compressed air stream of the first circuit through the channel of the first circuit 3 is supplied to a gas generator 4, the exhaust gases from which are supplied to a low pressure turbine 8, and from it through a mixer 9 and afterburner 10 to the main the jet nozzle 11, the compressed air stream of the second circuit is fed through the channel of the second circuit 12 through the mixer 9 and the afterburner 10 to the main jet nozzle 11, and the compressed air stream of the third circuit through the distribution device 14 is fed into the channel of the third circuit 15. Through the channel of the third circuit 15, a stream of compressed air is supplied through a switchgear 16 either to the nozzle of the third circuit 17 or through the afterburner 10 to the main jet nozzle 11.

The engine is regulated by switching from a three-circuit operation scheme to a two-circuit operation scheme and vice versa, as well as by changing the degree of the bypass engine by switching distributors 14 and 16 to the direction of compressed air flow and turning on afterburner 10. In small, take-off and maximum modes, as well as in transient conditions without boosting the engine, its operation is carried out according to the two-circuit scheme, and the compressed air flow of the third circuit through the distributor 14 and the second stage 2 of the adaptive Ntilator 1 is sent to the channel of the second circuit 12, and in cruising operation without boosting the engine, the compressed air flow of the third circuit through the channel of the third circuit 15 is fed into the nozzle of the third circuit 17. At maximum and transient modes of operation with boosting the engine, the compressed air flow of the third circuit is fed directly from the channel of the third circuit 15 through the afterburner 10 to the main jet nozzle 11.

The operator sets the main and transient modes of engine operation, as the engine operation parameters, the sensor 20 controls the braking temperature of the air flow at the engine inlet, using the sensors 21 determines the fuel consumption by time, the sensors 22 and 23 control the values of the rotational speed of the gas generator rotor and low pressure rotor .

Opening and closing of switchgears 14 and 16 for connecting and disconnecting a third-circuit channel is carried out according to the values of the reduced rotational speed of the low-pressure rotor N _{I pr} , determined by the physical frequency of rotation of the low-pressure rotor, calculated at the full temperature at the engine inlet:

,

,

where N _{I physical} - physical frequency of rotation of the low pressure rotor;

T ₀ is the standard temperature value to which the value of the rotational speed is given (according to GOST 4401-81 T ₀ = 288 K);

T ^* _in - the braking temperature of the air flow at the inlet to the engine.

In take-off mode, the engine operates as a conventional double-circuit turbojet engine, since the parameter N _{I pr is} higher than the limit value of switching the operating mode of the third circuit. Under these conditions, the control units of the adaptive fan 1 and switchgears 14 and 16 minimize the air flow in the channel of the third circuit 15, and the nozzle of the third circuit 17 is closed, as shown in FIG. 2 schematically illustrating a configuration of an engine without bleeding into a third circuit. The air stream entering the engine inlet passes through both stages 2 and 13 of the adaptive fan 1.

In the "low gas" mode, the engine is controlled as a conventional double-circuit turbojet engine with the afterburner 10 turned off (configuration without air sampling into the channel of the third circuit 15). Switchgears 14 and 16 minimize airflow in the third circuit channel, the third circuit nozzle 20 is closed, there is no compressed air supply from the third circuit channel 15 to the afterburner 10, as shown in FIG. 2. The entire air flow entering the engine inlet passes through both stages 2 and 13 of the adaptive fan 11.

The same engine operation pattern is maintained in modes with engine boosting in the conditions of subsonic flight, providing the maximum possible engine thrust. Under these conditions, the adaptive fan 1 operates at the maximum mode, thereby preventing a decrease in the parameter N _{I pr} due to a decrease in its rotation frequency, and the incoming air flow has a low full temperature.

At throttle cruising modes, characterized by lower speeds of the gas generator 4, with the afterburner 10 turned off, the adaptive fan operates at a low physical speed N _{I physical} , the value of the parameter N _{I pr} becomes lower than the specified value. Distribution devices 14 and 16 through the channel of the third circuit 15 direct the air flow into the nozzle of the third circuit 17, there is no air supply to the third circuit in the afterburner 10, as shown in FIG. 4. An increase in the bypass ratio of the engine with such a scheme is ensured by a higher air flow through the entire engine, the parameters of the working process in the engine are higher, and the total losses of the power plant are lower than in a power plant with a dual-circuit turbojet engine, which leads to a decrease in the effective specific fuel consumption in a turbojet engine.

At the maximum throttle operation, with forcing of the engine in supersonic flight conditions the fan 1 is operated at deep throttling modes due to a substantial rise in temperature T ^* _Rin braking air flow entering the engine. Switchgears 14 and 16 further direct the third circuit compressed air flow to the afterburner 17 directly from the third circuit channel 15, as shown schematically in FIG. 3. The supply of compressed air of the third circuit to the nozzle of the third circuit 17 is blocked by the switchgear 16, and the nozzle of the third circuit 17 remains closed. The operation of the engine is carried out according to the scheme characteristic of a supersonic ramjet engine. This increases the maximum flight thrust of the engine and, accordingly, ensures maximum flight speed.

In the case when the parameter N _{I pr} increases and its value exceeds a predetermined value without an operator's command to change the engine operating mode in a configuration with a compressed air flow of the third circuit into the afterburner 10 shown in FIG. 3, switchgears 14 and 16 shut off the supply of compressed air through the channel of the third circuit 15 to the afterburner 10, reduce the air flow in the third circuit to a minimum, thereby automatically transferring the engine to a dual-circuit operation (Fig. 2).

In transient modes of operation, the engine is controlled as follows.

When switching the motor from the maximum operation mode (FIG. 2) at the maximum with the forcing of the engine after the combustion of the afterburner 10 is first motor operates as a conventional turbojet engine enabled afterburner, but due to the increasing temperature T ^* _Rin airflow deceleration inlet into the engine, the value of the parameter N _{I pr} decreases and when it reaches the set boundary value, the distribution units 14 and 16 additionally direct the flow of compressed air of the third circuit into the afterburner 17 directly from the channel of the third circuit 15 (Fig. 3). At the same time, an increase in the flow rate of compressed air through the afterburner while maintaining its operating mode (the temperature of the gases after the afterburner does not change) allows to increase the engine thrust.

The engine adapts to the operating conditions characteristic of the deep throttle mode, approaching the appearance of a ramjet engine. As the engine is running in this mode, acceleration stops and the engine continues to work in this configuration, but at maximum speed with boosting the engine, providing a higher flight speed than in the configuration without taking compressed air into the channel of the third circuit 15.

Upon receipt of an operator’s command to change the operating mode to the maximum mode without forcing the engine, switchgears 14 and 16 reduce the air flow of the third circuit by blocking its supply to the afterburner 10, the fuel stops flowing into the afterburner 10. The engine goes into the configuration without flow compressed air into the channel of the third circuit 15 is again controlled as a dual-circuit turbojet engine with the afterburner 10 turned off.

When switching from the maximum operating mode with boosting the engine to cruising mode, the engine first goes into the configuration without taking compressed air into the channel of the third circuit 15. As the engine is operating in this mode, the speed of the low pressure rotor N _{I physical} decreases due to throttling of the engine, which leads to a decrease in the parameter N _{I pr}

When parameter N _I overcome the limit value, the distributors 14 and 16 increase the flow rate of compressed air in the channel of the third circuit 15, directing it to the nozzle of the third circuit 17 and turning the engine into a configuration with air intake into the third circuit and supplying it to the nozzle of the third circuit (Fig. . four). The air supply of the third circuit in the afterburner of the combustion chamber 10 is absent. The engine adapts to new operating conditions, acquiring the appearance of a dual-circuit turbojet engine with a higher degree of dual-circuit.

Thus, controlling the engine according to the parameters N _{I pr} and N _{I physical} at maximum and transient conditions with boosting the engine and supplying a stream of compressed air directly from the channel of the third circuit through the afterburner to the main jet nozzle allows to increase the flight thrust of the engine while maintaining fuel consumption.

Claims (1)

The method of operation of a three-circuit turbojet engine with an afterburner, which consists in the fact that the compressed air from the adaptive fan is divided into three streams, the stream of the primary circuit is fed into a gas generator, the exhaust gases from which are fed to a low pressure turbine, and from it through a mixer and afterburner to the main jet nozzle, the flow of the second circuit is fed through the mixer and the afterburner to the main jet nozzle, the flow of the third circuit through the switchgear is either supplied to the nozzle of the third circuit, or about through the afterburner into the main jet nozzle, set the main and transitional modes of the engine, as parameters of the engine control the braking temperature of the air flow at the inlet of the engine, the fuel consumption in time and the speed of the rotor of the gas generator and low pressure rotor, and regulate the work engine by switching from a three-circuit operation scheme to a two-circuit operation scheme and vice versa, as well as by changing the degree of the bypass engine by switching to switchgears directions of compressed air flows and the inclusion of the afterburner in the operation, and at low, take-off and maximum modes, as well as in transient modes without boosting the engine, its operation is carried out according to a two-circuit scheme, and the compressed air stream of the third circuit is sent to the secondary circuit channel, and to the cruising the mode of operation without boosting the engine, the compressed air stream of the third circuit through the channel of the third circuit is fed into the nozzle of the third circuit, characterized in that at maximum and transient modes of operation with force Engine Hovhan compressed airflow third circuit is supplied directly from the channel of the third circuit via the afterburner in the main jet nozzle, and the opening and closing of switching devices for connecting and disconnecting the channel of the third circuit is carried out according to the values of the relative frequency of low pressure rotor.

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