RU2574213C1 - Control over dual-flow turbojet engine with augmenter - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: claimed invention can be used fuel feed control systems of augmented dual-flow turbojet engine. Claimed control procedure consists in the measurement of pressure $$(p_c^{*})$$

behind the compressor and that $$(p_t^{*})$$

behind the turbine and the calculation of the pressure difference at the turbine $$({\pi }_{T\sum }^{*}=p_c^{*}/{р}_t^{*}).$$

Then, pressure difference variation rate $$(\delta {\pi }_{T\sum }^{*})$$

is defined to determine the fuel feed variation rate (δG_TA) at the feed into the combustion augmenter. At augmented conditions the fuel feed into the augmenter is adjusted subject to the ratio between said pressure difference variation rate and said fuel feed variation rate at the turbine $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TA})$$

to make it approximate to zero.

EFFECT: higher accuracy of fuel feed control.

2 cl, 4 dwg

Description

The invention relates to the field of aviation technology, and more specifically relates to the control of a turbojet dual-circuit engine with afterburner (TRDDF). The invention can mainly be used in control systems for fuel supply to the afterburner combustion chamber of a turbofan engine in forced modes.

It is well known that to control the gas turbine engine (GTE) of an aircraft, information obtained from sensors measuring the thermodynamic and dynamic parameters and rotor speed of a GTE is used.

A known method of automatic control of fuel supply, in which the control action of the regulator on the actuator acting on the fuel supply to the afterburner of the engine, is adjusted by an electronic program controller that controls in accordance with the control algorithm built into the control system, including the values of the tuning and control parameters, determining the fuel supply to the engine (RF patent No. 2308605).

, и подают для воздействия на исполнительный орган, определяющий топливоподачу в форсажную камеру сгорания (патент РФ №2464437).Also known is a method of controlling a turbojet dual-circuit engine with an afterburner (FC) in forced modes, in which, based on at least one control quantity and at least one measured quantity characterizing the operation mode of the turbocompressor part of the engine, using a mathematical model determine a value characterizing at least one control signal supplied to the Executive body; in this case, the fuel consumption in the main combustion chamber, the low-speed shaft rotational speed, the total air pressure behind the compressor are used as measured values, the total air temperature at the engine inlet and the angle (α _ores ) characterizing the position of the engine control lever are used as a control quantity (RUD); as a value that characterizes the control signal, use the fuel consumption G _TF supplied to the afterburner in forced modes, which is determined in accordance with the program according to the law $$(G_{t\mathrm{about}\mathrm{to}\mathrm{from}}+G_{tf})/(P_{\mathrm{to}}^{*}{\text{n}}_{\text{at}})=f(T_{\mathrm{at}x}^{*},{\alpha }_{R\mathrm{at}d})$$

, and serves to act on the executive body, which determines the fuel supply to the afterburner of combustion (RF patent No. 2464437).

, где $${Р}_{к}^{*}$$

- давление воздуха за компрессором, $$T_{вх}^{*}$$

- температура воздуха на входе в ГТД, а функция $$f(T_{вх}^{*})$$

- расчетная зависимость, полученная по математической модели из условия поддержания для данного «нового» (соответствующего состоянию на начало эксплуатации) двигателя в стандартных атмосферных условиях (САУ) при использовании «стандартного» топлива наиболее рационального (соответствующего наибольшему значению тяги) коэффициента избытка воздуха в форсажной камере α_Σ (см., например, под ред. Ю.Н. Нечаев, Теория авиационных двигателей, ч. 2, М., 2006, стр. 136-138).There is also a known method of controlling maximum forced modes based on a program of the type $$G_{tf}=R_{\mathrm{to}}^{*}f(T_{\mathrm{at}x}^{*})$$

where $$R_{\mathrm{to}}^{*}$$

- air pressure behind the compressor, $$T_{\mathrm{at}x}^{*}$$

- air temperature at the entrance to the gas turbine engine, and the function $$f(T_{\mathrm{at}x}^{*})$$

- the calculated dependence obtained from the mathematical model from the condition of maintaining for this “new” (corresponding to the state at the beginning of operation) engine in standard atmospheric conditions (ACS) when using “standard” fuel of the most rational (corresponding to the highest thrust value) coefficient of excess air in the afterburner chamber α _Σ (see, for example, under the editorship of Yu.N. Nechaev, Theory of aircraft engines, part 2, Moscow, 2006, pp. 136-138).

However, the law used in the well-known technical solutions, corresponding to the “new” engine as of the beginning of its operation, does not reflect the possible influence of changes (deterioration) in the characteristics of the engine components during its operation, deviation of atmospheric conditions from self-propelled guns, as well as other factors (features of the used fuel grade , air humidity, flow parameters in the afterburner, fuel atomization quality, etc.), due to the influence of which the operation modes of the main engine components are mismatched and, as a result, yours, a change in its characteristics. In this regard, the amount of fuel actually supplied to the FC at maximum forced modes may differ from that “calculated” value that corresponds to the maximum thrust of the turbofan engine. This leads to the fact that control of a gas turbine engine becomes less effective due to the impossibility of ensuring optimal combustion in the entire range of engine operating modes and, as a result, deterioration of the main engine parameters - its thrust and specific fuel consumption. Thus, this and other existing fuel supply systems in the FC provide a predetermined fuel flow that do not take into account the actual combustion process in the FC of a specific turbofan engine. In this regard, the correction of fuel consumption in the FC is required, the value of which depends on various factors, the influence of which can be mutually opposite, and its early determination is extremely difficult.

The determination of the necessary correction of fuel consumption in the FC can theoretically be carried out either by direct measurements capable of showing the efficiency of the combustion process (for example, the temperature of the gas or the composition of the products of combustion at the outlet of the FC), or by indirectly evaluating the combustion process from the dynamics of changes in the parameters available for measurement first of all, changes in pressure behind the turbine (pressure drop across the turbine) due to an increase in the gas temperature at the outlet of the FC with a change in the fuel supply.

As the closest analogue, a control method for a gas turbine engine with an afterburner has been selected (RF patent No. 2389890), in which the pressure and temperature of gases in the FC are measured in steady-state boosted modes. At the same time, a pulsating effect on the fuel consumption in the FC is increasing in frequency and, at the moment of increasing the completeness of combustion of the afterburning fuel, determined by an abrupt increase in the pressure and temperature of the gases in the FC, the frequency of the pulsating effect on the fuel consumption is recorded. Further, the consumption of afterburning fuel is reduced until the temperature of the gases in the FC drops to the initial one. The known method provides an increase in engine efficiency in afterburner modes.

и давления $${р}_{Ф}^{*}$$

газа в ФК при увеличении расхода топлива G_ТФ; при этом достижение температурой $${Т}_{Ф}^{*}$$

исходного значения (определенного по математической модели или в результате испытаний «нового двигателя», соответствующего началу эксплуатации) и свидетельствует о достижении «оптимального» значения расхода топлива G_ТФ.In the known technical solution, the correction of the fuel flow supplied to the FC in forced modes is performed as a result of the assessment of the rate of temperature change $$T_F^{*}$$

and pressure $$R_F^{*}$$

gas in FC with increasing fuel consumption G _TF ; while achieving temperature $$T_F^{*}$$

initial value (determined by a mathematical model or as a result of testing a “new engine” corresponding to the beginning of operation) and indicates the achievement of an “optimal” value of fuel consumption G _TF .

и выше, а также высокой радиальной и окружной неравномерности распределения этих параметров $${Т}_{Ф}^{*}$$

и $$p_{Ф}^{*}$$

.At the same time, measuring the pressure and temperature of the gas in the engine's FC during its operation with a sufficient degree of accuracy is practically impossible due to the high temperature level $$T_F^{*}~2000K$$

and higher, as well as high radial and circumferential uneven distribution of these parameters $$T_F^{*}$$

and $$p_F^{*}$$

.

The basis of the invention is the task of increasing the efficiency of the turbofan engine by obtaining the maximum possible thrust at maximum forced modes by adjusting the program for supplying fuel to the afterburner; the magnitude of this correction is determined by indirectly evaluating the combustion process from the dynamics of changes in the parameters available for measurement, in particular, changes in pressure behind the turbine (differential across the turbine) with a change in the fuel supply speed.

The technical result is an increase in the accuracy of fuel consumption control, which is necessary to maintain maximum thrust at maximum forced modes when changing fuel characteristics, air composition (humidity, etc.), changing the characteristics of its units in operation and changing the flow characteristics in the FC.

и давление за турбиной $$({р}_{т}^{*})$$

, вычисляют перепад давления на турбине $$({\pi }_{T\sum }^{*}=p_{к}^{*}/{р}_{т}^{*})$$

и определяют скорость изменения указанного перепада $$(\delta {\pi }_{T\sum }^{*})$$

, определяют скорость изменения расхода топлива (δG_ТФ), подаваемого в форсажную камеру сгорания, и на максимальных форсированных режимах регулируют подачу топлива в форсажную камеру сгорания в зависимости от величины отношения скорости изменения перепада давления на турбине к скорости изменения расхода топлива $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TФ})$$

.The achievement of the claimed technical result is ensured by the fact that in the method of controlling a turbojet dual-circuit engine with an afterburner, consisting in measuring the forced operation parameters of the engine and adjusting according to the results of measurements of the fuel flow supplied to the afterburner, according to the invention, the pressure is measured after the compressor $$(p_{\mathrm{to}}^{*})$$

and pressure behind the turbine $$(R_t^{*})$$

calculate the pressure drop across the turbine $$({\pi }_{T\sum }^{*}=p_{\mathrm{to}}^{*}/R_t^{*})$$

and determine the rate of change of the specified differential $$(\delta {\pi }_{T\sum }^{*})$$

, determine the rate of change of fuel consumption (δG _TF ) supplied to the afterburner, and at maximum forced modes, regulate the flow of fuel into the afterburner, depending on the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

.

, близким к нулю.It is advisable to regulate the fuel supply to the afterburner, providing the value of the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

close to zero.

в ФК через изменение давления за турбиной (перепада давления на турбине), характеризующего изменение этой температуры. В данном случае косвенное определение температуры газа $${Т}_{ф}^{*}$$

в ФК обеспечивает получение более точного значения этого параметра, поскольку в условиях реальной эксплуатации невозможно с достаточной точностью измерять температуры порядка 2000К и выше. Невысокая точность прямого измерения температуры газа $${Т}_{Ф}^{*}$$

в ФК, например, с использованием термопары обусловлена ее высокой радиальной и окружной неравномерностью распределения.Evaluation of the combustion efficiency with a change (increase) in the relative fuel supply is determined by indirectly determining the change in gas temperature $$T_f^{*}$$

in FC through a change in pressure behind the turbine (pressure drop across the turbine), characterizing the change in this temperature. In this case, the indirect determination of the gas temperature $$T_f^{*}$$

in FC provides a more accurate value of this parameter, since in real-life conditions it is impossible to measure temperatures of about 2000K and higher with sufficient accuracy. Low accuracy of direct measurement of gas temperature $$T_F^{*}$$

in FC, for example, using a thermocouple is due to its high radial and circumferential uneven distribution.

The invention is explained below with reference to illustrations and tables, where in FIG. Figure 1 shows the dependence of the completeness of fuel combustion in the FC on the coefficient of excess air. In FIG. Figure 2 shows the calculated dependences of engine thrust, gas temperature in the FC and the rate of change of pressure behind the turbine, depending on the rate of change of fuel consumption in the FC. In FIG. 3 is a block diagram of a fuel supply control system in the FC. In FIG. 4 shows tables 1 and 2.

и давление за турбиной $$({р}_{т}^{*})$$

. Далее вычисляют перепад давления на турбине $$({\pi }_{T\sum }^{*}=p_{к}^{*}/{р}_{т}^{*})$$

и определяют скорость изменения указанного перепада $$(\delta {\pi }_{Т\sum }^{*})$$

. Обычно расход форсажного топлива (до коррекции) регулируют по давлению за компрессором $$G_{ТФ}/{р}_{к}^{*}=f(T_{вх}^{*})$$

. На максимальных форсированных режимах определяют скорость изменения расхода топлива (δG_ТФ), подаваемого в ФК, и регулируют подачу топлива в ФК в зависимости от величины отношения скорости изменения перепада давления на турбине к скорости изменения расхода топлива $$(\delta {\pi }_{T\sum }^{*}/\delta G_{ТФ})$$

. Причем подачу топлива в форсажную камеру сгорания регулируют, обеспечивая значение отношения скорости изменения перепада давления на турбине к скорости изменения расхода топлива $$(\delta {\pi }_{T\sum }^{*}/\delta G_{ТФ})$$

, близким к нулю.The claimed method of controlling a turbojet dual-circuit engine with an afterburner consists in the fact that the engine operation parameters are measured in forced modes and the fuel flow supplied to the FC is controlled by the measurement results. In this case, the significant measured parameters include the pressure behind the compressor $$(p_{\mathrm{to}}^{*})$$

and pressure behind the turbine $$(R_t^{*})$$

. Next, the pressure drop across the turbine is calculated. $$({\pi }_{T\sum }^{*}=p_{\mathrm{to}}^{*}/R_t^{*})$$

and determine the rate of change of the specified differential $$(\delta {\pi }_{T\sum }^{*})$$

. Typically, afterburner fuel consumption (before correction) is controlled by pressure downstream of the compressor $$G_{TF}/R_{\mathrm{to}}^{*}=f(T_{\mathrm{at}x}^{*})$$

. At maximum forced modes, the rate of change of fuel consumption (δG _TF ) supplied to the FC is determined and the fuel supply to the FC is regulated depending on the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

. Moreover, the fuel supply to the afterburner is regulated, providing the value of the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

close to zero.

в ФК, что вследствие ограничения приведенного расхода через критическое сечение сопла приводит к росту полного давления перед соплом $${р}_{ф}^{*}$$

, а следовательно, за турбиной $${р}_{т}^{*}$$

и уменьшению перепада давления на турбине $${\pi }_{Т\sum }^{*}$$

. Хотя система автоматического управления двигателя в дальнейшем начнет «раскрывать» критическое сечение реактивного сопла для сохранения перепада давления на турбине $${\pi }_{Т\sum }^{*}$$

, но этот процесс гораздо более инерционный, чем рост температуры и давления в ФК. Таким образом, при увеличении подачи топлива в ФК имеет место снижение перепада давления на турбине со скоростью, определяемой инерционностью системы автоматического управления двигателя и изменением температуры вследствие подачи дополнительного топлива.When you change (for example, increase) the relative fuel supply G _TF in FC there is a dynamic change in gas temperature $$T_f^{*}$$

in FC, which, due to the limitation of the reduced flow rate through the critical section of the nozzle, leads to an increase in the total pressure in front of the nozzle $$R_f^{*}$$

and therefore behind the turbine $$R_t^{*}$$

and reducing the pressure drop across the turbine $${\pi }_{T\sum }^{*}$$

. Although the automatic engine control system in the future will begin to “reveal” the critical section of the jet nozzle to maintain the pressure drop across the turbine $${\pi }_{T\sum }^{*}$$

, but this process is much more inertial than the increase in temperature and pressure in the PC. Thus, with an increase in the fuel supply to the FC, there is a decrease in the pressure drop across the turbine at a speed determined by the inertia of the automatic engine control system and the temperature change due to the supply of additional fuel.

) в разных условиях будет неодинаковым. В области более высоких значений коэффициента избытка воздуха α_Σ значение коэффициента полноты сгорания η_ф в ФК также имеет высокий и практически постоянный уровень (см. фиг. 1). Следовательно, при увеличении подачи топлива G_ТФ также увеличивается и температура $$T_{ф}^{*}$$

. Однако по мере приближения к стехиометрическому значению в ядре потока (коэффициент избытка воздуха α_Σядра=1) полнота сгорания топлива начинает резко уменьшаться. При этом темп прироста температуры $$T_{ф}^{*}$$

также падает, а с дальнейшим ростом подачи топлива G_ТФ вследствие уменьшения эффективности его сгорания температура сначала перестает расти, а затем начинает падать.At the same rate of increase in fuel supply, an increase in temperature (hence, a decrease in the differential pressure drop across the turbine $${\pi }_{T\sum }^{*}$$

) under different conditions will be different. In the region of higher values of the coefficient of excess air α _{Σ, the} value of the coefficient of completeness of combustion η _f in the FC also has a high and almost constant level (see Fig. 1). Therefore, with increasing fuel supply G _TF , the temperature also increases $$T_f^{*}$$

. However, as we approach the stoichiometric value in the flow core (air excess coefficient α _{Σ core} = 1), the completeness of fuel combustion begins to decrease sharply. At the same time, the temperature growth rate $$T_f^{*}$$

also decreases, and with a further increase in fuel supply G _TF due to a decrease in the efficiency of its combustion, the temperature first ceases to increase, and then begins to fall.

и будет теоретическим пределом повышения тяги двигателя при форсировании при данных условиях.The moment of termination of temperature rise $$T_f^{*}$$

and will be the theoretical limit for increasing engine thrust during boost under given conditions.

вследствие снижения полноты сгорания топлива, а следовательно, и достижения максимально возможной тяги двигателя (см. фиг. 2).The claimed invention proposes to limit and stop the increase in fuel consumption with a sharp decrease in the pressure gradient behind the turbine (differential on the turbine), which indicates the cessation of temperature increase $$T_f^{*}$$

due to a decrease in the completeness of fuel combustion, and, consequently, the achievement of the maximum possible engine thrust (see Fig. 2).

The adopted control law helps to maintain the required thrust of the turbofan engine in forced modes while deteriorating the performance of its units with operating hours and thereby increases the efficiency of the turbofan engine.

, который, в свою очередь, зависит от фактического изменения температуры газа в форсажной камере $${Т}_{ф}^{*}$$

при изменении относительной величины подачи топлива. Момент достижения величиной $$(\delta {\pi }_{T\sum }^{*}/\delta G_{ТФ})$$

близкого к нулю значения и соответствует наиболее оптимальной величине расхода топлива, подаваемого в форсажную камеру. При указанном расходе топлива горение остается эффективным и обеспечивается получение максимально возможной тяги двигателя независимо от внешних факторов (погрешностей программы управления, изменения характеристик узлов в процессе эксплуатации, отклонения атмосферных условий на входе, теплотворной способности конкретного топлива и т.д.).In the proposed method, the maximum amount of fuel supplied to the FC TRDDF is determined not by a predetermined static dependence of fuel consumption, set by a priori laid down program in order to maintain the coefficient of excess air at the most optimal (minimum) level, but by a dynamic system. The dynamic system adjusts the initial fuel supply program based on feedback depending on the rate of change of the differential pressure (rate of change) of the turbine $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

, which, in turn, depends on the actual change in gas temperature in the afterburner $$T_f^{*}$$

when changing the relative amount of fuel supply. Moment of achievement $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

values close to zero and corresponds to the most optimal value of fuel consumption supplied to the afterburner. At the indicated fuel consumption, combustion remains efficient and provides the maximum possible engine thrust regardless of external factors (control program errors, changes in the characteristics of the units during operation, deviation of atmospheric conditions at the inlet, calorific value of a specific fuel, etc.).

(в блоке 3), давлению за компрессором $${р}_{к}^{*}$$

(в блоке 4) и давлению за турбиной (в блоке 5). По сигналам, поступающим с выходов блоков 3 и 4, в блоке 6 формируется и передается в насос-регулятор 2 сигнал, определяющий расход форсажного топлива G_ТФ по условию $$G_{ТФ}/{р}_{к}^{*}=f(T_{ВХ}^{*})$$

. При этом насос-регулятор 2 подает соответствующий расход топлива в форсажную камеру двигателя 1. Одновременно с этим по сигналам, поступающим с выходов блоков 4 и 5, в блоке 7 формируется сигнал, пропорциональный суммарной степени понижения давления в турбине $${\pi }_{T\sum }^{*}=p_{к}^{*}/{р}_{т}^{*}$$

. Управляющий блок 10, первоначально задавая некоторое приращение расхода форсажного топлива, формирует сигнал, пропорциональный скорости изменения расхода топлива (δG_ТФ), а дозирующее устройство 8 в соответствии с этим сигналом корректирует сигнал блока 6, в результате чего насос-регулятор 2 изменяет расход форсажного топлива, подаваемого в двигатель 1. В блоке 9 формируется сигнал, пропорциональный скорости изменения значения суммарной степени понижения давления в турбине $$(\delta {\pi }_{Т\sum }^{*})$$

, на основании этого сигнала и самого приращения расхода топлива ΔG_тф в блоке 10 формируется сигнал на коррекцию расхода форсажного топлива в зависимости от отношения скорости изменения перепада давления на турбине к скорости изменения расхода топлива $$(\delta {\pi }_{T\sum }^{*}/\delta G_{ТФ})$$

.In FIG. 3 shows a block diagram of a control system that implements the claimed method. In accordance with the block diagram of the fuel supply control system in the FC, the signals proportional to the value of the air temperature at the engine inlet are formed according to the measured parameters of engine 1 $$T_{\mathrm{at}x}^{*}$$

(in block 3), pressure downstream of the compressor $$R_{\mathrm{to}}^{*}$$

(in block 4) and the pressure behind the turbine (in block 5). According to the signals coming from the outputs of blocks 3 and 4, in block 6, a signal is generated and transmitted to the pump-controller 2, which determines the consumption of afterburning fuel G _TF according to the condition $$G_{TF}/R_{\mathrm{to}}^{*}=f(T_{\mathrm{AT}X}^{*})$$

. At the same time, the pump-regulator 2 supplies the corresponding fuel consumption to the afterburner of engine 1. At the same time, a signal proportional to the total degree of decrease in pressure in the turbine is generated from the outputs of blocks 4 and 5, in block 7 $${\pi }_{T\sum }^{*}=p_{\mathrm{to}}^{*}/R_t^{*}$$

. The control unit 10 initially setting some afterburner fuel increment generates a signal proportional to the fuel consumption rate of change (δG _TF) and the metering device 8 in accordance with this signal corrects the signal of the block 6, whereby the pump controller 2 adjusts the flow afterburner fuel supplied to the engine 1. In block 9, a signal is generated proportional to the rate of change of the value of the total degree of pressure decrease in the turbine $$(\delta {\pi }_{T\sum }^{*})$$

, on the basis of this signal and the increment of fuel consumption ΔG _tf in block 10, a signal is generated to correct the afterburner fuel consumption depending on the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

.

As an example illustrating the effect obtained, ALD-31F turbofan engines are considered in flight conditions at an altitude of H = 11 km at maximum speed.

. При этом следует иметь в виду, что одной из причин падения тяги двигателя является снижение степени форсирования (то есть повышение значения коэффициента избытка воздуха в форсажной камере α_Σ=1,13369 до α_Σ=1,15096).In table 1 (see Fig. 4), to simulate the influence of a possible deterioration of the engine parameters during its operation, the change in the main parameters with “1% degraded” values of the efficiency of the main components (KND, KVD, TVD and TND) is compared with the “calculated »The case when using the currently applicable law of fuel supply to the afterburner $$G_{TF}/P_{\mathrm{to}}^{*}=f(T_{\mathrm{AT}X}^{*})$$

. It should be borne in mind that one of the reasons for the drop in engine thrust is a decrease in the degree of forcing (that is, an increase in the coefficient of excess air in the afterburner α _Σ = 1,13369 to α _Σ = 1,15096).

In accordance with the description above, the proposed system for supplying fuel to the afterburner will increase the degree of engine boost (increase fuel supply) to achieve maximum thrust.

от коэффициента избытка воздуха в форсажной камере α_Σ в данных условиях полета без учета возможного изменения полноты сгорания топлива в форсажной камере η_ф (за единицу принято значение тяги двигателя при α_Σ=1,15096, соответствующей исходному закону регулирования подачи топлива в форсажную камеру сгорания.Table 2 (see Fig. 4) presents the calculated dependence of the relative thrust of the engine in question $$\overline{R}$$

from the coefficient of excess air in the afterburner α _Σ in these flight conditions without taking into account the possible change in the completeness of fuel combustion in the afterburner η _f (the unit thrust value is taken at α _Σ = 1.15096, which corresponds to the initial law of regulation of the fuel supply to the afterburner .

To take into account the effect of changes in the completeness of fuel combustion in the afterburner η _f on the dependence R _f = f (α _Σ ), one should use the results of tests of this engine at the TsIAM TsAM P.I. Baranov, who showed that with an increase in engine boost (i.e., a decrease in the coefficient of excess air to α _Σ ≈ 1.05), there was a constant increase in the value of afterburner thrust, and at α _Σ <1.05, its decrease was observed. If we take the value α _Σ ≈1.05 (see Table 2 bold italics) as the optimal value from the point of view of maximum afterburner thrust, then we can assume that the application of the proposed fuel supply control system in the FC will allow one to obtain a thrust gain ΔR = 2.9%.

, позволяет учитывать изменение параметров состояния двигателя и характеристик окружающей среды и обеспечивает прирост тяги.The proposed method of engine control, which consists in regulating the supply of fuel to the afterburner at maximum forced modes in terms of $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

, allows you to take into account changes in the parameters of the state of the engine and environmental characteristics and provides an increase in traction.

Claims (2)

1. The method of controlling a turbojet dual-circuit engine with an afterburner, which consists in the fact that in forced modes measure the parameters of the engine and according to the results of the measurements regulate the flow of fuel supplied to the afterburner, characterized in that they measure the pressure behind the compressor $$(p_{\mathrm{to}}^{*})$$

and pressure behind the turbine $$(R_t^{*})$$

calculate the pressure drop across the turbine $$({\pi }_{T\sum }^{*}=p_{\mathrm{to}}^{*}/R_t^{*})$$

and determine the rate of change of the specified differential $$(\delta {\pi }_{T\sum }^{*})$$

, determine the rate of change of fuel consumption (δG _TF ) supplied to the afterburner, and at maximum forced modes, regulate the flow of fuel into the afterburner, depending on the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

. 2. The control method according to claim 1, characterized in that the fuel supply to the afterburner is controlled, providing a value for the ratio of the rate of change of pressure drop across the turbine to the rate of change of fuel consumption $$(\delta {\pi }_{T\sum }^{*}/\delta G_{TF})$$

close to zero.

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