RU2720059C1 - Control method of gas turbine engine with afterburner combustion chamber - Google Patents

Abstract

FIELD: engine building.

SUBSTANCE: invention relates to aircraft engine building and can be used in electronic-hydromechanical systems for automatic control of multi-mode gas turbine engines (GTE) with afterburner combustion chamber (ACC). In the known method for control of gas turbine engine with afterburner combustion chamber (ACC) additionally measuring area of critical section of jet nozzle, generating a signal F equal to the ratio of the degree of reduction of gas pressure on the turbine to the measured area of the critical cross-section of the jet nozzle, generating a signal Frat equal to the ratio of the deviation of the current value of the signal F from its average value to its average value, preliminary by results of tests determining values Fgr and Fgr2, corresponding to values of signal Frat at start-up and extinction of afterburner respectively, when the signal Frat exceeds the preset positive value Fgr, the combustion in the afterburner combustion chamber is determined and the augmenter of the afterburner combustion chamber is switched off, and at start of afterburner combustion chamber with reduction of signal Frat below lower preset negative value Fgr2, extinguishing of afterburner combustion chamber is determined and supply of fuel into augmenter is stopped.

EFFECT: higher reliability of determination of combustion in afterburner combustion chamber, reduced weight of engine due to exclusion of flame sensors in afterburner combustion chamber and electric wires to them, and also increased speed of reaction of system in part of detection of combustion of fuel in afterburner combustion chamber.

3 cl, 1 dwg

Description

The invention relates to the field of aircraft engine manufacturing and can be used in electronic-hydromechanical systems for automatic control of multi-mode gas turbine engines (GTE) with afterburner combustion chamber (FCC).

Closest to the claimed invention in technical essence and the technical result achieved is a method of controlling a gas turbine engine with afterburner combustion chamber (FCC), which consists in the fact that the measured air temperature at the engine inlet, air pressure behind the compressor, the position of the engine control lever (ORE ), and the fuel consumption in the main combustion chamber (ACS) (main fuel consumption) is controlled by the fuel consumption in the FCC, according to the measured position of the ore and the differential pressure of the gas on the engine turbine unit They are called hydraulic cylinders for driving the shutter of the jet nozzle (PC), according to the measured throttle position, the air pressure behind the compressor and the air temperature at the engine inlet form a set value for the starting fuel consumption in the FCC, the starting fuel consumption of the afterburning fuel is fed to the FCC, the firing track unit is turned on and controlled ignition FKS according to the measured temperature of the gas in the FKS, if the ignition FKS did not occur, turn off the starting fuel consumption of the afterburner fuel and the unit of the fire track, increase the set value of the starting consumption of the afterburner fuel by 5%, feed into the FCC the starting consumption of afterburning fuel, turn on the firing track unit and control the ignition of the FCC according to the measured gas temperature in the FCC, if the FCC does not ignite, reduce the set value of the starting consumption of afterburning fuel by 5%, and submit it to the FCC boost fuel starting fuel, turn on the firing track unit and control the ignition of the FCS according to the measured gas temperature in the FCS, if the FCS is not ignited, increase the set value of the boost fuel starting fuel by 10%, feed the FCS starting flow fossil fuels, turn on the firing track unit and control the ignition of the FCS according to the measured temperature of the gas in the FCC, if the FKS ignition does not occur, reduce the set value of the starting fuel consumption of afterburner fuel by 10%, feed the starting flow rate of the afterburning fuel to the FCC, turn on the firing track unit »And control the ignition of the FCC according to the measured temperature of the gas in the FCC, if the ignition of the FCC did not occur, change the set value of the starting consumption of afterburning fuel with a resolution of 5% and repeat the entire procedure for starting the FCC and do this until Single latches FCC ignition if a predetermined fuel flow rate change exceeded 50% and the FCC ignition has not occurred, start-up attempts carried out is stopped and FCC regulations extraordinary engine (see. RF patent No. 2432478, cl. F02C 9/34, 2006).

As a result of the analysis of this method, it should be noted that in the selected control method, the start of the FCC is controlled by the measured gas temperature in the FCC. The gas temperature in the FCC can reach 2000 K, the measurement of such high temperatures is technically challenging. For example, when using thermocouples to measure them, it is necessary to protect them from high temperatures with a special purged housing that increases the reaction time of the thermocouple to a temperature change in the PCF, which leads to delays in the formation of the combustion signal. Such delays are unacceptable in the take-off and take-off modes of the aircraft. The operation of thermocouples at high temperatures reduces their resource, which leads to an increase in operating costs.

In addition, in the selected control method, the start of the FCC is controlled by the signal of the flame ionization sensor. The disadvantage of this solution is the decrease in the reliability of detection of combustion of the FCC as the resource is depleted. such sensors, when installed directly in the FCC, “burn out” and their sensitivity decreases.

To process this sensor, it is necessary to provide power to the sensor with a voltage of 400 V with a frequency of 2000 Hz. Such requirements lead to a complication of the equipment and an increase in its dimensions, as well as a decrease in reliability.

The technical result of the present invention is to increase the reliability of determining combustion in the FCC, reducing the weight of the engine by eliminating flame sensors in the FCC and electrical wires to them, as well as increasing the reaction rate of the system in terms of detecting fuel combustion in the FCC.

The specified technical result is achieved due to the fact that in the known method of controlling a gas turbine engine with afterburner combustion chamber (FCC), in which the fuel consumption is controlled by the measured air temperature at the engine inlet, air pressure behind the compressor, position of the engine control lever (ORE) FCC, measure the degree of decrease in gas pressure on the engine turbine, control the FCC start-up unit, new is that they additionally measure the critical sectional area of the jet nozzle, form the signal F equal to the ratio of the degree of decrease in gas pressure on the turbine to the measured critical cross-sectional area of the jet nozzle, a signal Frel is generated, which is equal to the ratio of the deviation of the current value of the signal F from its average value to its average value; first, threshold values Fgr and Fgp2 are determined from the results of tests of several engine samples corresponding to the values of the signal Frel when starting and extinguishing the afterburner, respectively, when the signal Frel exceeds the predetermined positive value Fgr before burning in the FCC and turn off the FCC start-up unit, and when the FCC is started, when the signal Frel decreases below the predetermined negative value Fgr2, the FCC extinction is determined and the fuel supply to the FCC is stopped.

In the particular case of the implementation of the claimed method, the value of Fg is reduced with decreasing pressure behind the compressor.

In the particular case of the implementation of the inventive method, the value of Fg2 is increased in absolute value as the degree of boosting the engine increases.

The essence of the claimed invention is illustrated by graphic materials on which a diagram of a gas turbine engine control system is presented.

The fuel consumption control system in the gas turbine engine contains a fuel master 1 in the FCC 2, to the inputs of which a temperature sensor 3 at the engine inlet, an ore control sensor 4, an air pressure sensor 5 behind the compressor are connected. The system also contains the first and second dividers 6 and 7; an air pressure sensor 5 behind the compressor is connected to the first input of the first divider 6, a gas pressure sensor 8 behind the turbine is connected to the second input of the first divider 6, the output of the first divider 6 is connected to the first input of the second divider 7, the critical section sensor 9 is connected to its second input jet nozzle. The output of the second divider 7 is connected to the average value filter 10 and to the first input of the adder 11, the output of the filter 10 is connected to the second input of the same, the output of the filter 10 is connected to the second input of the third divider 12, the output of the adder 11 is connected to the first input of it 12 is connected to the first comparator 13 with a threshold of operation Fgr and through the first key 14 to a second comparator 15 with a threshold of operation Fgr2. The first comparator 13 is connected to the control input of the first key 14 and to the control input of the second key 16. The second comparator 15 is connected to one of the inputs of the fuel master 1 in the FCC 2.

The system contains a third comparator 17, the input of which is connected to the ORE position sensor 4, and the output of the comparator 17 through the key 16 controls the inclusion of the ignition unit 18 of the FCS.

To implement the control method according to claim 2, the output of the air pressure sensor 5 behind the compressor must be connected to the control input of the first comparator 13.

To implement the control method according to claim 3, the system must further comprise a fourth divider 19 and a setter 20 of the value of the throttle position in full boost mode; the output of the fourth divider 19 must be connected to the control input of the second comparator 15, the sensor 4 of the ORE position 4 must be connected to the first input of the fourth divider 19, and the setter 20 to the second input.

The claimed system can be composed of known blocks and elements.

As sensors can be used standard sensors for monitoring the parameters of the gas turbine engine, for example, thermoresistive temperature sensors, resistive pressure sensors, standard linear differential transformers for measuring linear or angular displacements.

The dividers, totalizers, and keys used in the system are standard.

The unit 1 flow in the afterburner can implement the following well-known dependence:

As the average value filter 10, a low-pass filter can be used.

As the ignition unit 18 of the FCC, a known firing track launching unit (AOD) can be used.

The comparator 17 is standard with a pre-selected threshold.

To implement the system according to claim 1, as comparators 13 and 15, comparators with preselected thresholds of operation Fgr and Fgr2, respectively, can be used. To implement the system according to claim 2., the comparator 13 must be with a variable threshold (Fg), which varies depending on the signal at its control input. To implement the system according to claim 3. comparator 15 must be with a variable threshold (Fgr2) that varies depending on the signal at its control input. The thresholds for comparator 13 - Fgr and comparator 15 - Fgr2 can be selected by calculation or by test results.

To select the value of Fgr, a change in the signal Frel is recorded at the time the afterburner starts up at various engine operating modes during engine tests. The value of Fgr is selected by (20 ... 30)% below the minimum signal value recorded during successful starts of the afterburner, which ensures reliable detection of the successful launch of the afterburner. To select the value of Fgr2, the fuel supply to the afterburner is stopped at various modes of boosting the engine and the change in the signal Frel is recorded. The value of Fg2 is selected at least 30% less in absolute value than the maximum in absolute value of the deviation of the signal Frel from the zero value.

Reference 20 is a standard constant reference.

Key 14 is open when a logic zero signal is present at its control input.

Key 16 is closed when a logic zero signal is applied to its control input.

The system operates as follows.

The engine operating mode is set by moving the throttle (not shown in Fig.), The position of which is measured by the sensor 4. The threshold of the comparator 17 is selected so that it is triggered when the throttle is transferred to the afterburner.

The divider 6, according to the readings of the air pressure sensors 5 behind the compressor and the gas pressure sensor 8 behind the turbine, generates the value of the degree of decrease in the gas expansion pressure on the turbine (π _T ).

The divider 7 generates a signal F equal to the ratio π _T to the critical nozzle cross-sectional area (Scr) measured by the sensor 9. The low-pass filter 10 filters the signal F, getting the average signal value - F _cp . The adder 11 generates a deviation of the signal F from its average value F 'as the difference between the current value of the signal F and its average value F _c . The divider 12 generates a signal Frel equal to the ratio of the deviation of the current value of the signal F from its average value to its average value.

Frel = F '/ F _cp .

Changing the signal F is possible in the following cases:

1. Change π _T due to changes in the operating mode of the gas generator,

2. Change in the amount of burning fuel in the FCC.

In this case, the system should work in such a way that the comparators 13 or 15 work only on the second item.

This is achieved by choosing the thresholds for the operation of the comparators and the filter time constant 10 of the average value: a change in π _T due to a change in the operation mode of the gas generator is relatively slow, several times slower than a change due to fuel ignition in the FCS or a change in the critical section area of the jet nozzle. Therefore, with such a change in π _T , the signal value F _cp closely coincides with its current value F.

When the critical cross-sectional area changes, the gas pressure behind the turbine changes, which means the degree of decrease in gas pressure on the turbine, but Frel does not change, because an increase in Scr is proportional to a decrease in π _T.

Therefore, transients not associated with fuel combustion in the FCC do not cause the comparators 13 and 15 to trip.

In this case, while the comparator 13 is not triggered, the key 14 is open and the comparator 15 is turned off of the separator 12.

When the throttle is not in the afterburner, the control unit 1 generates zero total fuel consumption in the FCS 2, there is no combustion in the FCS 2, while a logic zero signal is generated at the output of the comparator 17 in accordance with the selected response threshold and, regardless of the state of the key 16, the ignition unit 18 FCC is off. The comparator 13, generates a logic zero signal, in accordance with this signal, the key 16 is closed.

When transferring the throttle to the afterburner, the fuel inverter 1 in the FCS according to the signals from the sensors 3 (TVX), 4 (ORE) and 5 (Rk), in accordance with dependence 1, starts to generate fuel consumption in the FCS 2 and by means of dispensers (not shown in Fig. ) feeds them to the FCC 2. At the same time, the main loop controller (not shown in Fig.) maintains a constant rotor speed and air pressure behind the compressor.

The transfer of the ore into the afterburner triggers the comparator 17, a logical unit signal is generated at its output, because tripping comparator 13 has not yet occurred, the key 16 is closed and the ignition unit 18 begins to work.

At the moment of filling the fuel collector of the FCC, fuel is sprayed and, as the ignition unit 18 is working, the fuel is ignited.

At the moment of fuel ignition in FCC 2, there is a sharp increase in gas pressure behind the turbine, measured by the sensor 8, as a result of which the degree of decrease in gas pressure on the turbine π _T decreases. During the transient process with respect to the π _T parameter, the average value of Fcp does not change, and the instantaneous value of the signal F decreases. A positive signal Frel arises, which leads to the operation of the first comparator 13, which closes the first key 14 and opens the second key 16.

When the second key 16 is opened, the ignition unit 18 is turned off. The process of launching FCC 2 ends.

When the key 14 is closed, the output of the divider 12 is connected to the second comparator 15, which is configured to operate at the time of extinguishment of the FCC 2.

After a time determined by the time constant of the filter 10, the signal Fcp reaches the value of the signal F, which leads to a decrease in the error F 'and a decrease in the signal Frel to zero.

If the FCC is running, then the second comparator 15 monitors the state of the signal Frel. At the time of the extinction of fuel in FCC 2, a sharp drop in gas pressure behind the turbine occurs, as a result of which the degree of decrease in gas pressure on the turbine π _T increases _. During the transition process, the mean value of Fcp does not change in the π _T parameter, and the instantaneous signal F increases. There is a negative signal Frel, which leads to the operation of the second comparator 15. The comparator 15 generates a signal of a logical unit to the master 1, which stops the dosing of fuel in FKS 2.

When the engine operating conditions change, for example, when the inlet pressure decreases, the air pressure behind the compressor decreases proportionally. Because afterburner controllers are configured to maintain a given degree of decrease in gas pressure on the turbine, the parameter π _T and therefore the value of the criterion F remain constant. With a decrease in pressure, the total fuel consumption in FCC 2 decreases, which leads to a drop in the signal Frel, and during the start of FCC 2 with a constant threshold of comparator 13, it will not work. To ensure the operation of the comparator 13, it is necessary to lower the threshold of its operation, depending on the amount of air pressure decrease behind the compressor, below the nominal value, for which the signal from the sensor 5 is sent to the control input of the comparator 13. The air pressure behind the compressor at the maximum engine operating mode is taken as the nominal value under normal atmospheric conditions.

Fuel is supplied to the FCC via several fuel collectors connected in series. Moreover, each of these collectors has a minimum fuel consumption through it, at which combustion is ensured. With a decrease in the degree of forcing, the total fuel consumption decreases smoothly, and the collectors are switched off discretely. In this case, a signal Frel exceeding (modulo) the value of Frel when the first collector is turned off can be generated, which will lead to the operation of the comparator 15 and a false stop of the dosing of fuel in the FCS, as when the FCS is extinguished.

To counter this factor, it is necessary to increase (modulo) the threshold of the comparator 15, depending on the degree of forcing the camera. In the minimum boost mode, the comparator 15 should be triggered when Frel is formed when 7 ... 10% of the total fuel consumption from the full boost mode is extinguished, and in the full boost mode, the comparator should be triggered when Fot is formed when 30% is extinguished.

The degree of engine forcing is set by moving the throttle. The signal characterizing the current degree of forcing is generated by a divider, the first input of which is connected to the ORE position sensor 4, and to the second - the ORE value setter 20 in the full boost mode:

Kf = RUD / RUDPF

For example, the ORE value at the small gas site is 15%, at the site of maximum operating mode - 65%, minimum forced mode - 70%, full forced 100%. The minimum boost mode will correspond to Kf = 0.7, to full boost - Kf = 1.

Thus, the threshold of the comparator 15 must be increased (modulo) with an increase in Kf above 0.7 and set to the maximum level at Kf = 1.

This control method allows to exclude combustion sensors in the FCC from the engine control system, which simplifies the control and monitoring equipment: excludes the analog processing channels of these sensors, which reduces the weight of the control system and engine and increases the reliability of the system.

This method improves the reliability of the determination of fuel combustion in the FCC, because It is based on the gas-dynamic properties of a gas turbine engine.

It should also be noted that the reaction time of the system is close to the time of ignition or extinction of the fuel and does not exceed 0.05 s.

Claims (3)

1. The method of controlling a gas turbine engine with a boost combustion chamber (FCC), which consists in the fact that according to the measured air temperature at the engine inlet, the air pressure behind the compressor, the position of the engine control lever, the fuel consumption in the afterburner is controlled, the degree of gas pressure decrease is measured on the turbine, control the FCC start-up unit, characterized in that they additionally measure the critical sectional area of the jet nozzle, generate a signal F equal to the ratio of the degree of decrease in gas pressure n and a turbine forms a signal Frel equal to the deviation of the current value of the signal F from its average value to its average value to the measured area of the critical section of the jet nozzle, and the threshold values Fgr and Fgr2 corresponding to the values of the signal Frel are preliminarily determined by the results of tests of several engine samples when starting and extinguishing the afterburner, respectively, then when the signal Frel exceeds the predetermined positive value Fgr, combustion in the afterburner is determined D combustion and shut off the machine run afterburner combustion chamber, and the running afterburner combustion chamber while reducing Fotn signal is below a predetermined negative value beforehand determined extinction Fgr2 afterburner combustion chamber and the fuel supply is stopped in the afterburner combustion chamber. 2. The control method according to claim 1, characterized in that the Fgr value is reduced with a decrease in pressure behind the compressor. 3. The control method according to claim 1, characterized in that the value of Fg2 is increased in absolute value as the degree of engine boosting increases.

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