A forced flame signal reconstruction method

Abstract

The application discloses a method for reconstructing afterburner flame signal, comprising the following steps: S1, obtaining engine oil supply time, obtaining reconstruction time according to the engine oil supply time, and setting cancellation reconstruction time; S2, setting signal trigger condition and signal reconstruction condition; S3, obtaining trigger signal, and judging whether the current altitude satisfies the signal trigger condition; S4, obtaining signal reconstruction data, and judging whether the signal reconstruction data satisfies the signal reconstruction condition; S5, reconstructing the afterburner flame signal according to the signal reconstruction data by a controller; and S6, waiting until the cancellation reconstruction time, and cancelling the afterburner flame signal reconstruction. The application adds an afterburner flame signal detection margin, reconstructs the afterburner flame signal, ensures timely and stable generation of the afterburner flame signal, and improves the reliability of the afterburner flame signal generation.

Description

Technical Field

[0001] This invention belongs to the field of aerospace engine afterburner flame detection technology, and particularly relates to a method for reconstructing afterburner flame signals. Background Technology

[0002] The afterburner flame signal is a crucial indicator of whether the engine's afterburner is functioning properly. If this signal is inaccurate, during normal operation, the controller will actively cut off the afterburner fuel supply, causing the engine's afterburner thrust enhancement function to fail. This is particularly problematic when the aircraft requires high thrust; a faulty afterburner flame signal will impact the aircraft's combat performance. During afterburner engagement, the electronic controller may misinterpret the afterburner as failing to ignite, preventing the engine from properly entering afterburner mode and resulting in a degraded thrust capability.

[0003] Flame signal detection in afterburner is usually achieved by an ion flame detector. The ion flame detector senses the flame temperature and generates an ion current. The flow of the ion current forms a potential difference and outputs a voltage. When the voltage exceeds a set threshold, an ion flame signal is generated. This signal is mainly affected by the combined influence of the flame detector's placement and the afterburner flame temperature.

[0004] The optimal location for flame detectors is usually determined within the entire flame envelope; therefore, the main factor affecting flame signal generation is the afterburner flame temperature. Under different engine inlet conditions, the generated flame temperature varies significantly, especially at high altitudes with low inlet temperatures, where the flame temperature is typically lower, resulting in an unstable flame signal. Furthermore, during the transition from start-up to normal stable operation in the afterburner, the flame temperature is unstable and uneven, further contributing to the unstable flame signal.

[0005] To avoid the impact of unstable flame signals on thrust function, a technical solution is needed that can acquire environmental information and reconstruct the afterburner flame signal at the appropriate time. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for reconstructing afterburner flame signals.

[0007] The present invention is achieved through the following technical solutions.

[0008] The present invention provides a method for reconstructing afterburner flame signals, comprising the following steps:

[0009] S1. Obtain the engine fuel injection time, obtain the reconfiguration time based on the engine fuel injection time, and set the cancel reconfiguration time;

[0010] S2. Set signal trigger conditions and signal reconstruction conditions;

[0011] S3. Acquire a trigger signal through a sensor. The trigger signal includes the current altitude and the start time of the afterburner fuel supply. The controller determines whether the current altitude meets the signal triggering conditions. If so, wait until the reconstruction time and proceed to step S4. Otherwise, repeat step S3.

[0012] S4. Obtain signal reconstruction data through sensors. The signal reconstruction data includes the fan boost ratio and the change value of the nozzle throat area. The controller determines whether the signal reconstruction data meets the signal reconstruction conditions. If it does, proceed to step S5; otherwise, end.

[0013] S5. The controller reconstructs the afterburner flame signal based on the signal reconstruction data;

[0014] S6. Wait until the time to cancel reconstruction, then cancel the afterburner flame signal reconstruction.

[0015] Preferably, the reconstruction time is the time after the afterburner fuel supply start-up time plus the engine fuel supply time.

[0016] Preferably, the signal triggering condition includes: reconstructing altitude;

[0017] The step of determining whether the current altitude meets the signal triggering conditions through the controller specifically refers to determining whether the current altitude is higher than or equal to the reconstructed altitude.

[0018] Preferably, the fan boost ratio refers to the ratio of the actual fan pressure ratio to the planned fan pressure ratio.

[0019] Preferably, the change value of the nozzle throat area refers to the actual value of the nozzle throat area minus the planned value of the nozzle throat area.

[0020] Preferably, the signal reconstruction conditions include: fan boost ratio deviation and nozzle throat area remaining unchanged;

[0021] The fan boost ratio deviation specifically refers to: the fan boost ratio being greater than or equal to the fan boost ratio deviation parameter;

[0022] The statement that the nozzle throat area remains unchanged specifically means that the change in nozzle throat area is less than or equal to the nozzle throat area deviation parameter.

[0023] Preferably, the value of the fan boost ratio deviation parameter is 1.01 to 1.3;

[0024] The value of the deviation parameter for the nozzle throat area is 0–70 cm. 2 .

[0025] Preferably, the cancellation time is the time when the afterburner flame signal is successfully reconstructed plus the reconstruction duration.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. Traditional afterburning flame signals only have one afterburning flame signal detection margin from the ion flame detector. This invention adds an additional afterburning flame signal detection margin, reconstructs the afterburning flame signal, ensures timely and stable generation of the afterburning flame signal, and improves the reliability of afterburning flame signal generation.

[0028] 2. Signal triggering conditions, signal reconstruction conditions, and reconstruction exit conditions are set, making the judgment of afterburner flame signals more accurate and avoiding the accidental triggering of afterburner flame signal reconstruction when it is not needed.

[0029] 3. Traditional mechanical flame detection is limited by the spatial constraints of ion flame detectors and temperature field changes, which may lead to inaccurate flame signal detection. This invention makes full use of the fan boost ratio and nozzle throat area parameters. The parameter changes are changes in the entire space and are not affected by physical location, thus having stronger adaptability. Attached Figure Description

[0030] Figure 1 This is a flowchart of the method provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of parameter changes at the moment of successful afterburner ignition provided in an embodiment of the present invention. Detailed Implementation

[0032] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0033] like Figure 1 As shown, the present invention provides a method for reconstructing afterburner flame signals, comprising the following steps:

[0034] S1. Obtain the engine fuel injection time, obtain the reconfiguration time based on the engine fuel injection time, and set the cancel reconfiguration time;

[0035] The reconstruction time is the time after the afterburner fuel supply start-up time plus the engine fuel supply time.

[0036] The afterburner flame is generated by igniting the afterburner start-up fuel in the afterburner I manifold in the ion flame detection zone. Therefore, the afterburner flame signal reconstruction is only performed after the afterburner fuel supply and ignition are successful. Thus, the trigger signal needs to obtain the moment of fuel supply in the jet before the reconstruction of the afterburner flame signal can be triggered.

[0037] After fuel injection, it takes a certain amount of time for ignition to succeed; the reconfiguration time is:

[0038] t = t0 + t cg

[0039] Where t is the reconfiguration time, t0 is the afterburner fuel supply time, and t cg This refers to the engine's fuel injection time. This parameter varies slightly between different engines, typically ranging from 0.3 to 0.5 seconds.

[0040] In this embodiment, the engine fuel injection time is 0.4 seconds, i.e., t cg = 0.4 seconds.

[0041] S2. Set signal trigger conditions and signal reconstruction conditions;

[0042] S3. Acquire a trigger signal through a sensor. The trigger signal includes the current altitude and the start time of the afterburner fuel supply. The controller determines whether the current altitude meets the signal triggering conditions. If so, wait until the reconstruction time and proceed to step S4. Otherwise, repeat step S3.

[0043] The signal triggering conditions include: reconstructing altitude;

[0044] The step of determining whether the current altitude meets the signal triggering conditions through the controller specifically refers to determining whether the current altitude is higher than or equal to the reconstructed altitude.

[0045] The unreliability of traditional afterburner flame signal detection is mainly concentrated under high-altitude, low-inlet pressure conditions. Afterburner flame signals under low-altitude, high-inlet conditions are usually not reconstructed, so it is necessary to set signal triggering conditions.

[0046] In this embodiment, the reconstructed altitude in the signal triggering condition is 8km. The afterburner flame signal reconstruction is only performed when the current altitude is higher than or equal to the reconstructed altitude H≥8km.

[0047] S4. Obtain signal reconstruction data through sensors. The signal reconstruction data includes the fan boost ratio and the change value of the nozzle throat area. The controller determines whether the signal reconstruction data meets the signal reconstruction conditions. If it does, proceed to step S5; otherwise, end.

[0048] The fan boost ratio refers to the ratio of the actual fan pressure ratio to the planned fan pressure ratio.

[0049] The change value of the nozzle throat area refers to the actual value of the nozzle throat area minus the planned value of the nozzle throat area.

[0050] The change in nozzle throat area serves as an intermediate adjustment variable for controlling the fan boost ratio, ensuring that the actual and planned fan pressure ratio values ​​follow each other well.

[0051] The signal reconstruction conditions include: fan boost ratio deviation and nozzle throat area remaining unchanged;

[0052] The fan boost ratio deviation specifically refers to: the fan boost ratio being greater than or equal to the fan boost ratio deviation parameter;

[0053] The statement that the nozzle throat area remains unchanged specifically means that the change in nozzle throat area is less than or equal to the nozzle throat area deviation parameter.

[0054] The value of the fan boost ratio deviation parameter is 1.01 to 1.3;

[0055] Depending on the import conditions, the fan boost ratio will deviate from the parameter to some extent.

[0056] The value of the deviation parameter for the nozzle throat area is 0–70 cm. 2 .

[0057] In this embodiment, the fan boost ratio deviation parameter K πf =1.05, nozzle throat area deviation parameter K A9 =10cm 2 .

[0058] like Figure 2 The diagram shown illustrates the parameter changes at the moment of successful ignition of the afterburner provided in this embodiment. The changes in fan boost ratio and nozzle throat area are suitable as signal reconstruction data and as reference data for afterburner flame signal reconstruction.

[0059] The process of afterburner flame formation is very short, typically on the order of 0.025 to 0.05 seconds. Meanwhile, the response time of the nozzle throat area is typically on the order of 0.5 to 1 second. In other words, during the afterburner flame generation process, the nozzle area usually remains constant, while the engine bypass duct is typically subsonic. Under the condition that the nozzle throat area remains constant, the pressure in the afterburner combustion chamber suddenly increases after successful ignition.

[0060] The pressure will be transmitted to the upstream fan outlet through the outer bypass duct. The fan rear pressure sensor located at this location will sense the change in pressure, causing a sudden increase in the fan pressure ratio, which satisfies the signal reconstruction condition.

[0061] At the moment of successful ignition in the afterburner, the actual fan pressure ratio rises rapidly, while the planned fan pressure ratio remains essentially the same as before successful ignition. When the actual fan pressure ratio is significantly higher than the planned value, and the nozzle throat area remains essentially unchanged, afterburner ignition is considered successful.

[0062] P if / P if_dem ≥K πf And |A8-A 8_dem |≤K A9

[0063] Among them, K πf For the fan boost ratio deviation parameter, KA9 A8 is the nozzle throat area deviation parameter, A8 is the actual value of the nozzle throat area, A 8_dem This is the planned value for the nozzle throat area.

[0064] S5. The controller reconstructs the afterburner flame signal based on the signal reconstruction data;

[0065] Inside the controller, the afterburner flame signal HY is reconstructed based on the signal reconstruction data. cg =1.

[0066] The controller can control the engine based on the afterburner signal.

[0067] S6. Wait until the time to cancel reconstruction, then cancel the afterburner flame signal reconstruction.

[0068] When the afterburner is operating stably, the actual value of the fan pressure ratio P if and fan pressure ratio planned value P if_dem The follow-up is good. At this time, there is no parameter change characteristic of the sudden increase in the actual fan pressure ratio during afterburner ignition. Therefore, the reconstruction signal must be cancelled to avoid affecting the normal operation of afterburner. The flame signal needs to be detected by the actual ion flame detector.

[0069] The cancellation time is the moment when the afterburner flame signal is successfully reconstructed plus the reconstruction duration.

[0070] In this embodiment, the reconstruction duration is 0.25 seconds, that is:

[0071] t s =t1+t dg

[0072] Among them, t s t1 is the time when the reconstruction is cancelled, t1 is the time when the afterburner flame signal is successfully reconstructed, and t dg The duration of the refactoring.

[0073] Traditional afterburning flame signals only have one detection margin for the ion flame detector. This invention adds an additional detection margin for the afterburning flame signal, reconstructs the afterburning flame signal, ensures timely and stable generation of the afterburning flame signal, and improves the reliability of afterburning flame signal generation.

[0074] The system sets signal triggering conditions, signal reconstruction conditions, and reconstruction exit conditions, which makes the judgment of afterburner flame signals more accurate and avoids erroneous triggering of afterburner flame signal reconstruction when it is not needed.

[0075] Traditional mechanical flame detection is limited by the spatial constraints of ion flame detectors and temperature field changes, which may lead to inaccurate flame signal detection. This invention makes full use of the fan boost ratio and nozzle throat area parameters. The parameter changes are changes in the entire space and are not affected by physical location, thus having stronger adaptability.

Claims

1. A method for reconstructing afterburner flame signals, characterized in that, Includes the following steps: S1. Obtain the engine fuel injection time, obtain the reconfiguration time based on the engine fuel injection time, and set the cancel reconfiguration time; S2. Set signal trigger conditions and signal reconstruction conditions; S3. Acquire a trigger signal through a sensor. The trigger signal includes the current altitude and the start time of the afterburner fuel supply. The controller determines whether the current altitude meets the signal triggering conditions. If so, wait until the reconstruction time and proceed to step S4. Otherwise, repeat step S3. S4. Obtain signal reconstruction data through sensors. The signal reconstruction data includes the fan boost ratio and the change value of the nozzle throat area. The controller determines whether the signal reconstruction data meets the signal reconstruction conditions. If it does, proceed to step S5; otherwise, end. S5. The controller reconstructs the afterburner flame signal based on the signal reconstruction data; S6. Wait until the time to cancel reconstruction, then cancel the afterburner flame signal reconstruction; The reconstruction time is the time after the afterburner fuel supply start-up time plus the engine fuel supply time. The signal triggering conditions include: reconstructing altitude; The step of determining whether the current altitude meets the signal triggering condition through the controller specifically refers to: determining whether the current altitude is higher than or equal to the reconstructed altitude. The signal reconstruction conditions include: fan boost ratio deviation and nozzle throat area remaining unchanged; The fan boost ratio deviation specifically refers to: the fan boost ratio being greater than or equal to the fan boost ratio deviation parameter; The phrase "no change in nozzle throat area" specifically means that the change in nozzle throat area is less than or equal to the nozzle throat area deviation parameter. The cancellation time is the time when the afterburner flame signal is successfully reconstructed plus the reconstruction duration; the cancellation time is used to terminate the afterburner flame signal reconstruction.

2. The afterburner flame signal reconstruction method as described in claim 1, characterized in that, The fan boost ratio refers to the ratio of the actual fan pressure ratio to the planned fan pressure ratio.

3. The afterburner flame signal reconstruction method as described in claim 1, characterized in that, The change value of the nozzle throat area refers to the actual value of the nozzle throat area minus the planned value of the nozzle throat area.

4. The afterburner flame signal reconstruction method as described in claim 1, characterized in that, The value of the fan boost ratio deviation parameter is 1.01~1.3; The value of the deviation parameter for the nozzle throat area is 0~70cm. 2 .

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