A method for fuel supply in the afterburner outer region when a carrier-based aircraft engine encounters temperature distortion during takeoff

Abstract

This application belongs to the field of aero-engine design, and is a method for afterburner outer-zone fuel supply when a carrier-based aircraft engine encounters temperature distortion during takeoff. After it is determined that the engine encounters temperature distortion, the afterburner outer-zone fuel supply law is activated. By separately calculating the outer-zone fuel flow correction coefficient related to the total pressure after the high-pressure compressor, the outer-zone fuel flow at different temperatures related to the correction coefficients of the inlet temperature and throttle lever angle, and the outer-zone fuel flow correction coefficient under different total pressures after the high-pressure compressor, a new afterburner outer-zone fuel supply law is obtained to control the afterburner outer-zone fuel flow under distortion. When exiting the temperature distortion, if the difference in the outer-zone fuel flow between the new law and the original law is large, the outer-zone fuel flow is gradually transitioned from large to small through a transition algorithm to achieve a smooth transition from the afterburner outer-zone fuel flow designed by the present invention to the original designed afterburner outer-zone fuel flow, quickly restoring to the normal working state and ensuring the aircraft takeoff thrust requirement.

Description

Technical Field

[0001] This application belongs to the field of aeroengine design, and particularly relates to a method for supplying fuel to the outer afterburning area when a carrier-based aircraft engine encounters temperature distortion during takeoff. Background Art

[0002] When a carrier-based aircraft takes off from an aircraft carrier, due to the existence of the deflector, the high-temperature exhaust gas (tail jet) discharged by the engine may be inhaled by the aircraft intake duct, resulting in temperature distortion at the engine inlet. In severe cases, it may induce engine instability. To address this problem, previously, only by closing the adjustable vane angle of the compressor, the engine's ability to resist temperature distortion was improved. Through research, it was found that under the condition of ensuring the thrust of the main engine of the engine remains unchanged, reducing the fuel flow rate in the outer area of the afterburner can effectively weaken the unstable combustion pulsation caused by the nozzle being subcritical due to the temperature distortion at the engine inlet, and reduce the pulsation impact through the forward transmission of the engine bypass, thereby improving the overall stability of the engine. In summary, reducing the fuel flow rate in the outer area of the afterburner can also effectively reduce the temperature of the engine tail jet and the intensity of temperature distortion at the engine inlet, which is beneficial to improving the engine stability.

[0003] The current solution mainly reduces the fuel flow rate in the outer area by adjusting the flow coefficient downward. This adjustment method can only achieve an overall downward adjustment of the fuel in the outer area, with a large step compared to the non-distorted state; and when the engine inhales less high-temperature tail jet (smaller temperature rise at the inlet) or when it exits the temperature distortion state, the engine thrust loss is relatively large.

[0004] Therefore, how to control the engine to adopt a method of reducing the fuel flow rate in the outer area when encountering temperature distortion; when inhaling less high-temperature tail jet or when exiting the temperature distortion, reducing the engine thrust loss is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a method for supplying fuel to the outer afterburning area when a carrier-based aircraft engine encounters temperature distortion during takeoff, so as to solve the problem that in the prior art, using the method of reducing the fuel flow rate in the outer area to reduce the temperature distortion intensity will result in a large engine thrust loss when inhaling less high-temperature tail jet or when exiting the temperature distortion.

[0006] The technical solution of this application is: A method for supplying fuel to the outer afterburning area when a carrier-based aircraft engine encounters temperature distortion during takeoff, including:

[0007] Judge whether the engine enters the afterburning state or the "engine encounters temperature distortion" flag is 1. If so, start the fuel supply law for the outer afterburning area; if not, do not start;

[0008] Obtain the total pressure after the high-pressure compressor P 31 parameters and calculate the outer area fuel flow correction coefficient f under different total pressures after the high-pressure compressoro1 ( P 31 ), according to the inlet temperature T 1 and the throttle lever angle correction coefficient f o3 (PLA), calculate the outer zone fuel flow f at different temperatures o2 ( T 1), according to the outer zone fuel flow correction coefficient f under different total pressures after the high-pressure compressor o1 ( P 31 ), the outer zone fuel flow f at different temperatures o2 ( T 1) and the throttle lever angle correction coefficient f o3 (PLA), calculate the afterburner outer zone flow under the new law W fao2 ; the afterburner outer zone fuel flow under the original law is W fao1 ;

[0009] Judge whether to exit the temperature distortion. If so, start timing. If at the moment of exit | W fao1 - W fao2 | ≤ C kg / h, then the afterburner outer zone fuel supply law is in accordance with W fao1 control; if at the moment of exit | W fao1 - W fao2 | > C kg / h, then within T seconds, transition from W fao2 to W fao1 , and the transition algorithm is:

[0010] W faox (n) = W faox (n - 1) + W fao1 (n) - W faox (n - 1)] × ΔT / T

[0011] In the formula, n—the current cycle number, n = 1 when just meeting the exit condition; W faox ——During the transition from W fao2 to W fao1 in the process of W fao , control the engine during the transition. When n = 1 Wfaox = W fao2 ; ΔT - transition time, which is 0 at the moment when the exit condition is just met; both T and C are constants;

[0012] When the time is greater than T seconds, directly adopt W fao1 control.

[0013] Preferably, the specific control formula for the fuel supply law in the afterburner outer region under the new law is:

[0014] f o1 ( P 31 ) = a * P 31

[0015] f o2 ( T 1) = b * T 1^4 - c * T 1^3 + d * T 1^2 - e * T 1 + f

[0016] W fao2 = [f o1 ( P 31 ) * f o2 ( T 1) * g + h] * f o3 (PLA) (kg / h)

[0017] In the formula, a, b, c, d, e, f, g, and h are all constants.

[0018] Preferably, the calculation method of the throttle lever angle correction coefficient is:

[0019] When PLA ≤ A°, f o3 ( PLA ) = 0;

[0020] When A° < PLA ≤ B°, f o3 ( PLA ) = ( PLA -A) / (B - A);

[0021] When PLA > B°, f o3 ( PLA ) = 1;

[0022] In the formula, A and B are both constants.

[0023] A method for afterburner outer-zone fuel supply when a carrier-based aircraft engine encounters temperature distortion during takeoff. After it is determined that the engine encounters temperature distortion, the afterburner outer-zone fuel supply law is activated. By separately calculating the outer-zone fuel flow correction coefficient related to the total pressure after the high-pressure compressor, the outer-zone fuel flow at different temperatures related to the inlet temperature and throttle lever angle correction coefficient, and the outer-zone fuel flow correction coefficient under different total pressures after the high-pressure compressor, a new afterburner outer-zone fuel supply law is obtained to control the afterburner outer-zone fuel flow under distortion. When exiting the temperature distortion, if the difference between the outer-zone fuel flow under the new law and the original law is large, the outer-zone fuel flow is gradually transitioned from large to small through a transition algorithm. When the engine inhales less high-temperature exhaust jet or exits the temperature distortion state, a smooth transition from the afterburner outer-zone fuel flow designed by the present invention to the original designed afterburner outer-zone fuel flow is achieved, quickly restoring to the normal working state to ensure the aircraft takeoff thrust requirement. Brief Description of the Drawings

[0024] To more clearly illustrate the technical solutions provided in this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0025] Figure 1 It is a schematic diagram of the overall process of this application;

[0026] Figure 2 It is a schematic diagram of the afterburner outer-zone fuel supply amount varying with the atmospheric temperature when there is temperature distortion and no temperature distortion at the takeoff moment of this application. Detailed Embodiment

[0027] To make the purpose, technical solutions, and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0028] A method for afterburner outer-zone fuel supply when a carrier-based aircraft engine encounters temperature distortion during takeoff, as Figure 1 shown, includes the following steps:

[0029] Step S100, Engine Temperature Distortion State Judgment

[0030] Judge whether the engine enters the afterburner state or the "engine encounters temperature distortion" flag is 1. Specifically, it is whether there is temperature distortion at the takeoff moment under the afterburner state. If so, activate the afterburner outer-zone fuel supply law; if not, do not activate.

[0031] The initial value of the "temperature distortion exists at takeoff" flag is defaulted to "0". When the inlet temperature rise, throttle lever angle, and aircraft wheel load signal simultaneously meet the relevant conditions, the "temperature distortion exists at takeoff" flag is set to "1". When any of the inlet temperature rise, throttle lever angle, and aircraft wheel load signal does not meet the relevant conditions, the flag is set to "0".

[0032] The value of the "temperature distortion exists at takeoff" flag can be directly obtained through the existing temperature distortion signal, and the details are not elaborated here.

[0033] Through simulation calculations, the afterburner outer-zone fuel supply flow rates in the states of temperature distortion existing and not existing at takeoff are shown in Figure 2 , where the upper curve is the variation of the afterburner outer-zone fuel supply flow rate with temperature when the "temperature distortion exists at takeoff" flag is "0"; the lower curve is the variation of the afterburner outer-zone fuel supply flow rate with temperature when the "temperature distortion exists at takeoff" flag is "1". It can be seen that when the atmospheric temperature is below 15 °C (288 K), the afterburner outer-zone fuel supply flow rates in the two states are basically the same. As the temperature rises, the afterburner outer-zone fuel supply flow rate in the state of temperature distortion existing at takeoff gradually decreases relative to the state of temperature distortion not existing at takeoff, and the decreasing amplitude gradually increases with the increase of the atmospheric temperature.

[0034] Step S200, control of the afterburner outer-zone fuel supply law

[0035] Obtain the total pressure after the high-pressure compressor P 31 parameters and calculate the outer-zone fuel flow correction coefficient f under different total pressures after the high-pressure compressor o1 ( P 31 ), according to the inlet temperature T 1 and the throttle lever angle correction coefficient f o3 (PLA) calculate the outer-zone fuel flow f at different temperatures o2 ( T 1), according to the outer-zone fuel flow correction coefficient f o1 ( P 31 ) under different total pressures after the high-pressure compressor, the outer-zone fuel flow f o2 ( T 1) at different temperatures and the throttle lever angle correction coefficient f o3 (PLA) calculate the afterburner outer-zone flow rate under the new law W fao2 ; the afterburner outer-zone fuel flow rate under the original law is W fao1 ;

[0036] The above different states and different temperatures are different nodes during the engine operation. For example, at a certain typical state point, when calculating, parameters such as the inlet temperature and pressure at the typical state point are taken as a set of parameters for one calculation.

[0037] Preferably, the specific control formula for the fuel supply law in the afterburner outer region under the new law is:

[0038] f o1 ( P 31 ) = a * P 31

[0039] f o2 ( T 1) = b * T 1^4 - c * T 1^3 + d * T 1^2 - e * T 1 + f

[0040] W fao2 = [f o1 ( P 31 ) * f o2 ( T 1) * g + h] * f o3 (PLA)(kg / h)

[0041] In the formula, a, b, c, d, e, f, g, and h are all constants, and the values of these constants can be changed according to different engine types.

[0042] It can be seen that the flow rate in the afterburner outer region under the new law mainly changes with the temperature. When the inlet temperature of the engine exceeds the normal temperature range of the aeroengine by a small amount, the reduced flow coefficient is small. When the inlet temperature of the engine exceeds the normal temperature range of the aeroengine by a large amount, the reduced flow coefficient is large, thus preventing a large step from occurring between the small temperature distortion and the non-distorted state, and the difference in the flow coefficient is small when approaching the exit temperature distortion.

[0043] Preferably, the calculation method for the throttle lever angle correction coefficient is:

[0044] When PLA ≤ A°, f o3 ( PLA ) = 0;

[0045] When A° < PLA ≤ B°, f o3 ( PLA ) = ( PLA -A) / (B - A);

[0046] When PLA > B°, f o3 ( PLA ) = 1;

[0047] Wherein, both A and B are constants and are adjusted according to different engine models.

[0048] Step S300, exiting temperature distortion

[0049] Judge whether to exit temperature distortion. If so, start timing. If at the moment of exiting, | W fao1 - W fao2 | ≤ C kg / h, then the fuel supply law in the afterburner outer zone is controlled according to W fao1 ; If at the moment of exiting, | W fao1 - W fao2 | > C kg / h, then transition from W fao2 to W fao1 within T seconds. The transition algorithm is:

[0050] W faox (n) = W faox (n - 1) + W fao1 (n) - W faox (n - 1)] × ΔT / T

[0051] Wherein, n is the current cycle number, and n = 1 when the exit condition is just met; W faox ——During the transition from W fao2 to W fao1 in the process of W fao , control the engine during the transition. When n = 1 W faox = W fao2 ; ΔT is the transition time, which is the 0 moment when the exit condition is just met; T and C are both constants;

[0052] When the time is greater than T seconds, directly adopt W fao1 control.

[0053] When exiting temperature distortion, according to the absolute value of the difference between the afterburner outer-zone fuel flow rate under the original law and that under the new law, it is divided into three intervals, and each interval is controlled according to different modes. When the difference between the afterburner outer-zone fuel flow rate under the original law and that under the new law is small at the moment of exit, it can be controlled according to the original law; when the difference in fuel flow rate between the two laws is large at the moment of exit, it is divided into multiple cycles, and the outer-zone fuel flow rate is reduced by a certain amount in each cycle until it is reduced to a certain value. If this value is within the normal range of the outer-zone fuel flow rate, there is no need to control the value of the outer-zone fuel flow rate anymore, and it can be controlled according to the normal fuel supply law; if it still exceeds, the outer-zone fuel flow rate has dropped to a certain value, and it can be directly controlled according to the original law.

[0054] The values of n and T are adjusted according to the specific engine type.

[0055] After this application determines that the engine encounters temperature distortion, it activates the afterburner outer-zone fuel supply law. By separately calculating the outer-zone fuel flow correction coefficient related to the total pressure after the high-pressure compressor, the outer-zone fuel flow rate at different temperatures related to the inlet temperature and throttle lever angle correction coefficient, and the outer-zone fuel flow correction coefficient under different total pressures after the high-pressure compressor, a new afterburner outer-zone fuel supply law is obtained to control the afterburner outer-zone fuel flow rate under distortion. When exiting temperature distortion, if the difference between the outer-zone fuel flow rate under the new law and the original law is large, the outer-zone fuel flow rate is gradually transitioned from large to small through a transition algorithm. When the engine inhales less high-temperature exhaust jet or exits the temperature distortion state, a smooth transition from the afterburner outer-zone fuel flow rate designed in the present invention to the original designed afterburner outer-zone fuel flow rate is achieved, quickly restoring to the normal working state, and ensuring the aircraft takeoff thrust requirement.

[0056] Thus, it is possible to reduce the afterburner outer-zone fuel flow rate to different extents according to the actual situation of the inlet temperature rise, and ensure the engine stability on the basis of largely retaining the engine thrust performance.

[0057] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for fuel supply in the afterburner outer region when a carrier-based aircraft engine encounters temperature distortion during takeoff, characterized in that, Including: Judge whether the engine enters the afterburning state or the "engine encounters temperature distortion" flag is 1. If so, start the fuel supply law for the outer afterburning area; if not, do not start. Obtain the total pressure P at the outlet of the high-pressure compressor 31 parameters and calculate the correction coefficient f of the outer-zone fuel flow at different total pressures at the outlet of the high-pressure compressor o1 (P 31 ), calculate the outer-zone fuel flow f at different temperatures according to the inlet temperature T1 and the throttle lever angle correction coefficient f o3 (PLA), calculate the outer-zone fuel flow f at different temperatures according to the correction coefficient f of the outer-zone fuel flow at different total pressures at the outlet of the high-pressure compressor o2 (T1), according to the correction coefficient f of the outer-zone fuel flow at different total pressures at the outlet of the high-pressure compressor o1 (P 31 ), the outer-zone fuel flow f at different temperatures o2 (T1) and the throttle lever angle correction coefficient f o3 (PLA), calculate the afterburning outer-zone flow W under the new law fao2 ; The fuel flow rate in the additional force outer region under the original rule is W fao1 ; Determine whether to exit the temperature distortion. If so, start timing. If at the moment of exit |W fao1 -W fao2 | ≤ C kg / h, then the fuel supply law in the outer afterburning area is controlled according to W fao1 ; if at the moment of exit |W fao1 -W fao2 | > C kg / h, then transition from W fao2 to W fao1 within T seconds, and the transition algorithm is: W faox W(n) = W faox W(n - 1)+[W fao1 (n)-W faox (n - 1)]×ΔT / T Where n is the current cycle number. When the exit condition is just met, n=1. faox ——From W fao2 Transition to W fao1 W in the process fao , control the engine during the transition period, when n = 1 W faox =W fao2 ; ΔT - transition time, when the exit condition is just met, it is time 0; T and C are both constants; When the time is greater than T seconds, directly adopt W fao1 Control.

2. The afterburner outer region fuel supply method for a carrier-based aircraft engine during takeoff when encountering temperature distortion as described in claim 1, characterized in that The specific control formula for the fuel supply law in the outer afterburning area under the new law is: f o1 (P 31 ) = a * P 31 f o2 (T1) = b * T1^4 - c * T1^3 + d * T1^2 - e * T1 + f W fao2 = [f o1 (P 31 ) * f o2 (T1) * g + h] * f o3 (PLA) (kg / h) In the formula, a, b, c, d, e, f, g, and h are all constants.

3. The afterburner outer region fuel supply method for a carrier-based aircraft engine during takeoff when encountering temperature distortion as described in claim 2, characterized in that, The calculation method of the throttle lever angle correction coefficient is: When PLA ≤ A°, f o3 (PLA) = 0; When A° < PLA ≤ B°, f o3 (PLA) = (PLA - A) / (B - A); When PLA > B°, f o3 (PLA) = 1; In the formula, A and B are both constants.

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