Air engine air super temperature early warning method and system

Abstract

This application provides a method and system for early warning of bleed air overheating in aero-engines, belonging to the field of health monitoring and control technology for aero-engine bleed air systems. The method includes: S1, constructing a dynamic prediction model for the hot-side outlet temperature of the aero-engine precooler; S2, introducing the rate of change of ambient temperature to correct the cold-side inlet temperature and substituting the corrected cold-side inlet temperature into the dynamic prediction model for the hot-side outlet temperature of the aero-engine precooler to calculate the hot-side outlet temperature of the aero-engine precooler; S3, introducing a first-order inertial delay to filter the hot-side outlet temperature of the aero-engine precooler to obtain the filtered hot-side outlet temperature of the aero-engine precooler; S4, dynamically calculating the precooler thermal load overload coefficient; S5, constructing a dynamic early warning trigger logic to optimize the engine bleed air overheating early warning. The method of this application solves the problem of false alarms or unnecessary bleed air cutoff caused by precooler thermal load overload and decreased heat exchange efficiency during the descent phase in existing bleed air overheating early warning methods.

Description

Technical Field

[0001] This application relates to the field of health monitoring and control technology for aero-engine bleed air systems, specifically to a method and system for early warning of overheating of aero-engine bleed air. Background Technology

[0002] The bleed air system of civil aircraft engines is a core secondary energy system, providing compressed air for critical airborne systems such as cabin air conditioning and pressurization, wing anti-icing, fuel tank inerting, and hydraulic tank pressurization. Its reliability directly affects flight safety. During the descent phase of flight, the bleed air system is prone to overheating warnings and triggering unplanned bleed air cutoff, including single-engine bleed air failure and dual-engine bleed air failure modes. Although bleed air failure itself does not directly cause an aircraft crash, it can trigger a series of chain safety problems such as cabin depressurization, loss of wing anti-icing capability, and malfunction of the fuel tank inerting system, forcing the crew to execute emergency descent procedures, seriously affecting flight safety and flight regularity.

[0003] In existing technologies, engine bleed air systems typically employ a combination of high-pressure and low-pressure bleed air supply. During aircraft descent, the engine operates at low speeds or near idle. At this time, the outlet pressure of the low-pressure compressor is insufficient to meet the air requirements of the onboard systems, and the bleed air system automatically switches to high-pressure bleed air mode. The bleed air temperature at the high-pressure compressor outlet can reach over 500°C, and must pass through a precooler to exchange heat with the cold-side air from the engine fan, reducing the temperature to below 200°C before being supplied to downstream users.

[0004] However, a unique thermodynamic contradiction exists during descent: as the flight altitude decreases, the ambient atmospheric temperature increases linearly, causing the cold-side inlet temperature of the precooler to rise accordingly. This reduces the heat exchange temperature difference in the precooler, significantly decreasing its heat exchange efficiency. Simultaneously, during descent, the aircraft is typically decelerating, with engine fan speeds at lower speeds and insufficient airflow to the cold side, further deteriorating the precooler's heat exchange effect. The combined effect of these factors makes it highly likely that the hot-side outlet temperature of the precooler will reach the system's set over-temperature protection threshold, triggering a bleed air over-temperature alarm and automatically cutting off the bleed air supply.

[0005] It is important to note that most of these overheating alarms and bleed air cutoffs are non-intrinsic malfunctions, meaning they are not caused by hardware damage or functional failure of the bleed air system itself. Instead, they are false alarms or protective malfunctions resulting from the specific flight conditions during descent and the inherent heat transfer characteristics of the precooler. These malfunctions not only increase the operational burden and flight risks for the crew but also lead to unnecessary flight diversions and engine return for maintenance, resulting in significant economic losses. Currently, existing technologies have not proposed an effective solution for the non-intrinsic overheating problem of engine bleed air during descent. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of this application is to provide an aero-engine bleed air overheat warning method and system, which can solve the problem of false alarms or unnecessary bleed air cut-off caused by precooler heat load overload and heat exchange efficiency reduction during the descent phase of the existing bleed air overheat warning method.

[0007] Specifically, on the one hand, this application provides a method for early warning of bleed air overheating in an aircraft engine, which includes the following steps: S1. Construct a dynamic prediction model for the hot-side outlet temperature of an aero-engine precooler: ; in, The hot-side outlet temperature of the aircraft engine precooler; This refers to the hot-side inlet temperature of the aero-engine precooler. This refers to the cold-side inlet temperature of the aero-engine precooler. For the heat exchange efficiency of the aircraft engine precooler; S2. The ambient temperature change rate is introduced to correct the cold side inlet temperature, and the corrected cold side inlet temperature is substituted into the dynamic prediction model of the hot side outlet temperature of the aero-engine precooler to calculate the hot side outlet temperature of the aero-engine precooler. S3. Add precooler thermal inertia delay correction, introduce a first-order inertia delay to filter the hot edge outlet temperature of the aero-engine precooler, and obtain the filtered hot edge outlet temperature of the aero-engine precooler. The calculation formula is as follows: ; in, t represents the thermal inertia time constant of the aero-engine precooler, in seconds; S4. Dynamically calculate the precooler heat load overload factor : ; in, The bleed air overheat warning threshold, when When the temperature at the hot edge outlet of the aero-engine precooler exceeds the bleed air overheat warning threshold, there is a risk of thermal overload. S5. Construct dynamic early warning trigger logic: During the descent phase, when the precooler heat load overload condition, the descent phase judgment condition and the engine low speed condition are met simultaneously, the bleed air over-temperature early warning optimization logic is triggered, an early warning message is issued and the precooler cold side flow adjustment or bleed air load adjustment is executed. If the heat load overload continues to increase, the bleed air cut-off protection is triggered.

[0008] Preferably, in step S5, the precooler heat load overload condition is: Duration exceeding the preset time threshold ; The descent phase is determined by the current altitude change rate. ; The low-speed operating conditions of the engine are: the low-pressure rotor speed of the aero engine. Set a threshold.

[0009] Preferably, the dynamic correction of the cold edge inlet temperature by introducing the rate of change of ambient temperature in step S2 is specifically as follows: ; in, Current flight altitude Due to localized ambient temperature deviation, The ambient temperature at the current altitude is calculated based on the international standard atmospheric model.

[0010] Preferably, in step S4 It is at least one of 260℃, 280℃ or other over-temperature warning thresholds.

[0011] Preferably, the precooler cold side flow rate adjustment in step S5 includes increasing the fan air valve opening; the bleed air load adjustment includes temporarily shutting down non-critical air supply systems.

[0012] Preferably, the condition for triggering the bleed air cutoff protection in step S5 is: after performing cold side flow regulation or bleed air load regulation, the thermal load overload factor is [value missing]. The temperature continues to rise and remains above the preset threshold or the filtered hot-side outlet temperature of the aero-engine precooler. The outlet temperature threshold has been exceeded.

[0013] Preferably, in step S3, the thermal inertia time constant of the aero-engine precooler is determined by the precooler structural parameters and airflow characteristics.

[0014] Preferably, the preset time threshold in step S5 According to the air intake overheat warning threshold Configure matching settings.

[0015] Preferably, after adjusting the cold side flow rate of the precooler or the bleed air load in step S5, if If the temperature drops below 0, the warning will be lifted.

[0016] On the other hand, this application provides an aero-engine bleed air overheat warning system for an aero-engine bleed air overheat warning method, which includes a precooler hot side outlet temperature dynamic prediction model construction unit, a cold side inlet temperature correction unit, a thermal inertia delay correction unit, a precooler thermal load overload coefficient calculation unit, and a dynamic warning triggering logic construction unit. The precooler hot edge outlet temperature dynamic prediction model building unit is used to build a dynamic prediction model for the hot edge outlet temperature of aero-engine precoolers. The cold-side inlet temperature correction unit is used to correct the cold-side inlet temperature by incorporating the ambient temperature change rate, and then substitutes the corrected cold-side inlet temperature into the dynamic prediction model for the hot-side outlet temperature of the aero-engine precooler to calculate the hot-side outlet temperature of the aero-engine precooler. The thermal inertial delay correction unit introduces a first-order inertial delay to filter the outlet temperature of the aero-engine precooler hot edge outlet temperature, thus obtaining the filtered aero-engine precooler hot edge outlet temperature. The precooler heat load overload factor calculation unit dynamically calculates the precooler heat load overload factor. The dynamic early warning triggering logic construction unit constructs dynamic early warning triggering logic to optimize the engine bleed air over-temperature early warning logic.

[0017] Compared with the prior art, the beneficial effects of this application are as follows: (1) The air bleed air overheat warning method provided in this application can reduce the false alarm rate. When the air engine state changes abruptly or the valve operates, an abnormal high temperature spike with a very short duration, such as 280°C lasting for 1 second, or a temperature peak exceeding 260°C lasting for 30 seconds, may be generated. Traditional logic may misjudge this. The method in this application avoids false alarms caused by instantaneous temperature fluctuations by introducing a precooler thermal load overload coefficient and thermal inertia delay correction.

[0018] (2) The air bleed air overheating early warning method provided in this application can improve the robustness of the system. This application can dynamically identify the air engine precooler thermal load overload condition during the descent phase, thereby intervening in advance, reducing unnecessary air bleed air cut-off, optimizing the early warning, and improving the robustness of the system.

[0019] (3) The air bleed air overheating early warning method provided in this application can adapt to complex environments. This application can combine the rate of change of ambient temperature and altitude changes to improve the adaptability of the model during descent and ensure the accuracy of the early warning.

[0020] (4) The air bleed air overheating early warning method provided in this application is easy to implement in engineering. The method in this application is based on existing sensor data, requires no additional hardware, is easy to embed into existing air bleed air control systems, and has a very wide range of engineering application scenarios. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall process of the aircraft engine bleed air overheat warning method of this application; Figure 2 This is a schematic diagram of the structure of the aircraft engine bleed air overheat warning system in the embodiments of this application; Figure 3 This is a schematic diagram of the heat exchange principle of the precooler in the embodiments of this application; Figure 4 This is a flowchart of the optimization method for early warning of bleed air overheating in an embodiment of this application; Figure 5 This is a schematic diagram illustrating the change of atmospheric ISA ambient temperature with altitude during the descent phase, as defined in this application embodiment. Figure 6 This is a schematic diagram illustrating the dynamic prediction and filtering effect of the precooler hot edge outlet temperature in an embodiment of this application; Figure 7 This is a schematic diagram of the triggering and adjustment timing of the exhaust gas overheat warning optimization logic in the embodiments of this application. Detailed Implementation

[0022] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings.

[0023] Specifically, on the one hand, this application provides a method for early warning of bleed air overheating in aero-engines, such as... Figure 1 As shown, it includes the following steps: S1. Construct a dynamic prediction model for the hot-side outlet temperature of an aero-engine precooler: ; in, The hot-side outlet temperature of the aircraft engine precooler; This refers to the hot-side inlet temperature of the aero-engine precooler. This refers to the cold-side inlet temperature of the aero-engine precooler. For the heat exchange efficiency of the aircraft engine precooler; S2. The ambient temperature change rate is introduced to correct the cold side inlet temperature, and the corrected cold side inlet temperature is substituted into the dynamic prediction model of the hot side outlet temperature of the aero-engine precooler to calculate the hot side outlet temperature of the aero-engine precooler.

[0024] The specific steps for dynamically correcting the cold-side inlet temperature by introducing the rate of change of ambient temperature are as follows: ; in, Current flight altitude Due to localized ambient temperature deviation, The ambient temperature at the current altitude is calculated based on the international standard atmospheric model.

[0025] S3. Add precooler thermal inertia delay correction, introduce a first-order inertia delay to filter the hot edge outlet temperature of the aero-engine precooler, and obtain the filtered hot edge outlet temperature of the aero-engine precooler. The calculation formula is as follows: ; in, is the thermal inertia time constant of the aero-engine precooler, in seconds, determined by the precooler's structural parameters and airflow characteristics. t is the precooler's thermal inertia time, in seconds. This represents the rate of change of the filtered hot-side outlet temperature of the aero-engine precooler over time, expressed in degrees Celsius per second.

[0026] S4. Dynamically calculate the precooler heat load overload factor : ; in, The bleed air overheat warning threshold, when This indicates that the hot-side outlet temperature of the aero-engine precooler exceeds the bleed air overheat warning threshold, posing a risk of thermal overload. It is at least one of 260℃, 280℃ or other over-temperature warning thresholds.

[0027] S5. Construct dynamic early warning trigger logic: During the descent phase, when the precooler heat load overload condition, the descent phase judgment condition and the engine low speed condition are met simultaneously, the bleed air over-temperature early warning optimization logic is triggered, an early warning message is issued and the precooler cold side flow adjustment or bleed air load adjustment is executed. If the heat load overload continues to increase, the bleed air cut-off protection is triggered.

[0028] The precooler overload conditions are as follows: Duration exceeding the preset time threshold Preset time threshold According to the air intake overheat warning threshold Configure matching settings.

[0029] The descent phase is determined by the current altitude change rate. .

[0030] The low-speed operating conditions of the engine are: the low-pressure rotor speed of the aero engine. Set a threshold.

[0031] Among them, the cold side flow regulation of the precooler includes increasing the opening of the fan air valve; the bleed air load regulation includes temporarily shutting down non-critical air-using systems.

[0032] The condition for triggering the bleed air cutoff protection is: after performing cold side flow regulation or bleed air load regulation, the thermal load overload factor... The temperature continues to rise and remains above the preset threshold or the filtered hot-side outlet temperature of the aero-engine precooler. The outlet temperature threshold has been exceeded.

[0033] Secondly, this application provides an aero-engine bleed air overheat warning system for the aforementioned aero-engine bleed air overheat warning method, which includes a precooler hot side outlet temperature dynamic prediction model construction unit, a cold side inlet temperature correction unit, a thermal inertia delay correction unit, a precooler thermal load overload coefficient calculation unit, and a dynamic warning triggering logic construction unit.

[0034] The precooler hot edge outlet temperature dynamic prediction model building unit is used to build a dynamic prediction model for the precooler hot edge outlet temperature of aero-engines.

[0035] The cold-side inlet temperature correction unit is used to correct the cold-side inlet temperature by incorporating the ambient temperature change rate, and then substitutes the corrected cold-side inlet temperature into the dynamic prediction model for the hot-side outlet temperature of the aero-engine precooler to calculate the hot-side outlet temperature of the aero-engine precooler. The thermal inertial delay correction unit introduces a first-order inertial delay to filter the outlet temperature of the aero-engine precooler hot edge outlet temperature, thus obtaining the filtered aero-engine precooler hot edge outlet temperature.

[0036] The precooler heat load overload factor calculation unit dynamically calculates the precooler heat load overload factor.

[0037] The dynamic early warning triggering logic construction unit constructs dynamic early warning triggering logic to optimize the engine bleed air over-temperature early warning logic. Specific implementation examples: This embodiment provides an optimized method for early warning of bleed air overheating in aero-engines, which is particularly suitable for early warning scenarios of bleed air overheating caused by precooler thermal load overload during the descent phase. The bleed air system of an aircraft engine includes a left engine and a right engine, each connected to a precooler via bleed air ducts. For example... Figure 2 The diagram shows the structure of a single-engine bleed air system. The precooler's hot-side inlet connects to the engine's 5th / 9th stage bleed air outlet, while the hot-side outlet connects to downstream air systems such as the wing anti-icing system and air conditioning system. The precooler's cold-side outlet connects to a fan air valve for regulating the precooler's cold-side flow rate, and the cold-side outlet discharges the heat-exchanged air outside the engine. Temperature sensors are installed at both the precooler's hot-side inlet and outlet to collect bleed air temperature in real time.

[0039] Precooler heat exchange principle: like Figure 3 As shown, the core task of the precooler is to exchange heat between the high-temperature, high-pressure air (hot side) drawn from the engine and the ram air (cold side), reducing the hot side outlet temperature to a safe range that the downstream system can withstand. The heat exchange efficiency is affected by the hot side inlet temperature, the cold side inlet temperature, the cold side flow rate, the hot side flow rate, and the precooler's own heat exchange efficiency characteristics.

[0040] Early warning methods: like Figure 1 and Figure 4 As shown, the optimized method for early warning of bleed air overheating in this embodiment includes the following steps: S1. Construct a dynamic prediction model for the hot edge outlet temperature of the aero-engine precooler.

[0041] Based on the heat exchange principle of the precooler, the following model for predicting the hot edge outlet temperature of the precooler is established in this embodiment: in: This refers to the precooler hot-side outlet temperature, which is also the engine bleed air outlet temperature, in °C.

[0042] The temperature at the hot edge inlet of the precooler, which is also the temperature at the engine bleed air inlet, is collected in real time by a temperature sensor and is measured in °C.

[0043] The temperature at the cold side inlet of the precooler is the ambient temperature, expressed in °C.

[0044] The heat exchange efficiency of the precooler is a dynamic parameter that varies with flight altitude, cold side flow rate, and hot side flow rate. It is obtained by referring to a table based on the heat exchange efficiency curve provided by the precooler manufacturer.

[0045] During the descent phase, the engine operates at low speeds, and the high-pressure stage bleed air temperature can reach over 500°C, as can the precooler hot-side inlet temperature. Significantly increased.

[0046] Step S2: Introduce the ambient temperature change rate to correct the cold edge inlet temperature.

[0047] like Figure 5 As shown, the International Standard Atmosphere (ISA) ambient temperature varies with altitude according to the International Standard Atmosphere (ISA) rate of change. During descent, the ambient temperature increases linearly with decreasing altitude. Cold edge inlet temperature. This directly affects the heat exchange capacity of the precooler. Increased ambient temperature will lead to an increase in the cold side inlet temperature, reducing heat exchange efficiency.

[0048] In this embodiment, the ambient temperature change rate is introduced to dynamically correct the cold edge inlet temperature: ; in: The ambient temperature is calculated based on the international standard atmospheric model and follows the ISA temperature-altitude rate of change. Current flight altitude, provided by the aircraft's air data system; The local ambient temperature deviation is calculated by the aircraft's total temperature sensor and static temperature sensor.

[0049] This correction allows for real-time acquisition of accurate cold-side inlet temperature, improving the accuracy of precooler outlet temperature prediction.

[0050] Step S3: Introduce precooler thermal inertia delay correction.

[0051] As a heat exchange device, the precooler has a certain thermal inertia, meaning that temperature changes are delayed. To avoid false alarms caused by instantaneous temperature fluctuations, this embodiment introduces a first-order inertial delay element to filter the outlet temperature: ; in: The thermal inertia time constant of the precooler is determined by the precooler's structural parameters and airflow characteristics. In this embodiment, it is taken as... Second; This is the outlet temperature of the precooler hot side after filtering.

[0052] like Figure 6 As shown, the filtered outlet temperature curve is smoother, effectively filtering out high-frequency noise and instantaneous fluctuations, making the early warning judgment more stable and reliable.

[0053] Step S4: Dynamically calculate the precooler heat load overload factor.

[0054] Define the precooler heat load overload factor as follows: ; in, This is the bleed air overheat warning threshold. Based on airworthiness requirements and system design, this embodiment uses [the threshold value]. And it lasts for 30 seconds to trigger or And it triggers for 1 second. When When the temperature at the hot edge outlet of the precooler exceeds the warning threshold, it indicates that there is a risk of overload in the heat load.

[0055] Step S5: Construct dynamic early warning trigger logic.

[0056] During the descent phase, this embodiment sets the following three conditions to trigger the bleed air overheat warning optimization logic when they are met simultaneously: Precooler heat load overload condition: precooler hot edge outlet temperature after filtering Corresponding heat load overload factor For more than the set time In this embodiment Seconds to avoid triggering false alarms due to instantaneous overheating.

[0057] Determination criteria for descent phase: Current altitude change rate This means the aircraft is in the descent phase. This condition is obtained through the aircraft's air data system to ensure that the optimization logic is activated only during the descent phase.

[0058] Engine low-speed operating conditions: Engine low-pressure rotor speed Less than a preset threshold. In this embodiment, the value is... As a condition for determining low-speed operation, the engine bleed air is usually switched to high-pressure stage bleed air, and the bleed air temperature increases significantly.

[0059] When all three conditions above are met simultaneously, the system triggers the bleed air overheat warning optimization logic, such as... Figure 7 As shown.

[0060] Phase 1, Early Warning and Adjustment: The system issues an "overload warning" message for the precooler heat load, indicating the risk of overload in the precooler heat load, and automatically adjusts the cold side flow of the precooler, such as increasing the opening of the fan air valve to increase the cold side flow and improve heat exchange efficiency. At the same time, if conditions permit, it temporarily shuts down non-critical air-consuming systems such as auxiliary cooling systems to reduce the bleed air load.

[0061] Phase Two: Continuous Monitoring: The system continuously monitors the heat load overload factor. The changing trend. If, after implementing adjustment measures, Once the value gradually drops below 0, the warning is lifted and the system returns to normal.

[0062] Phase Three, Disconnection Protection: If after implementing adjustment measures, The value continues to rise, exceeding the second preset threshold. In this embodiment, the value is taken as follows: If the outlet temperature after filtering exceeds 286℃, the system determines it as an unrecoverable over-temperature fault, triggers the bleed air cut-off protection, automatically closes the corresponding bleed air pressure regulating shut-off valve, and sends a "bleed air fault" alarm to the unit. At the same time, the critical system is maintained by supplying air from the engine on the other side through the isolation valve.

[0063] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A method for early warning of bleed air overheating in an aero-engine, characterized in that: It includes the following steps: S1. Construct a dynamic prediction model for the hot edge outlet temperature of an aero-engine precooler: ； in, The hot-side outlet temperature of the aircraft engine precooler; This refers to the hot-side inlet temperature of the aero-engine precooler. This refers to the cold-side inlet temperature of the aero-engine precooler. For the heat exchange efficiency of the aircraft engine precooler; S2. The ambient temperature change rate is introduced to correct the cold side inlet temperature, and the corrected cold side inlet temperature is substituted into the dynamic prediction model of the hot side outlet temperature of the aero-engine precooler to calculate the hot side outlet temperature of the aero-engine precooler. S3. Add precooler thermal inertia delay correction, introduce a first-order inertia delay to filter the hot edge outlet temperature of the aero-engine precooler, and obtain the filtered hot edge outlet temperature of the aero-engine precooler. The calculation formula is as follows: ； in, t represents the thermal inertia time constant of the aero-engine precooler, in seconds, and t represents the thermal inertia time of the precooler. S4. Dynamically calculate the precooler heat load overload factor : ； in, The bleed air overheat warning threshold, when When the temperature at the hot edge outlet of the aero-engine precooler exceeds the bleed air overheat warning threshold, there is a risk of thermal overload. S5. Construct dynamic early warning trigger logic: During the descent phase, when the precooler heat load overload condition, the descent phase judgment condition and the engine low speed condition are met simultaneously, the bleed air over-temperature early warning optimization logic is triggered, an early warning message is issued and the precooler cold side flow adjustment or bleed air load adjustment is executed. If the heat load overload continues to increase, the bleed air cut-off protection is triggered.

2. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: In step S5, the precooler heat load overload condition is: Duration exceeding the preset time threshold ; The descent phase is determined by the current altitude change rate. ; The low-speed operating conditions of the engine are: the low-pressure rotor speed of the aero engine. Set a threshold.

3. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: In step S2, the ambient temperature change rate is introduced to dynamically correct the cold edge inlet temperature. Specifically, this is as follows: ； in, Current flight altitude Due to localized ambient temperature deviation, The ambient temperature at the current altitude is calculated based on the international standard atmospheric model.

4. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: In step S4 It is at least one of 260℃, 280℃ or other over-temperature warning thresholds.

5. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: Step S5 includes adjusting the cold side flow of the precooler by increasing the opening of the fan air valve; and adjusting the bleed air load by temporarily shutting down non-critical air systems.

6. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: The condition for triggering the bleed air cutoff protection in step S5 is: after performing cold side flow regulation or bleed air load regulation, the thermal load overload factor... The temperature continues to rise and remains above the preset threshold or the filtered hot-side outlet temperature of the aero-engine precooler. The outlet temperature threshold has been exceeded.

7. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: In step S3, the thermal inertia time constant of the aero-engine precooler is determined by the precooler structural parameters and airflow characteristics.

8. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: Preset time threshold in step S5 According to the air intake overheat warning threshold Configure matching settings.

9. The method for early warning of bleed air overheating in aero-engines according to claim 1, characterized in that: After adjusting the cold side flow rate or bleed air load of the precooler in step S5, if If the temperature drops below 0, the warning will be lifted.

10. An aircraft engine bleed air overheat warning system for use in the aircraft engine bleed air overheat warning method according to any one of claims 1-6, characterized in that: It includes a precooler hot-side outlet temperature dynamic prediction model building unit, a cold-side inlet temperature correction unit, a thermal inertia delay correction unit, a precooler heat load overload coefficient calculation unit, and a dynamic early warning triggering logic building unit. The precooler hot edge outlet temperature dynamic prediction model building unit is used to build a dynamic prediction model for the hot edge outlet temperature of aero-engine precoolers. The cold-side inlet temperature correction unit is used to correct the cold-side inlet temperature by incorporating the ambient temperature change rate, and then substitutes the corrected cold-side inlet temperature into the dynamic prediction model for the hot-side outlet temperature of the aero-engine precooler to calculate the hot-side outlet temperature of the aero-engine precooler. The thermal inertial delay correction unit introduces a first-order inertial delay to filter the outlet temperature of the aero-engine precooler hot edge outlet temperature, thus obtaining the filtered aero-engine precooler hot edge outlet temperature. The precooler heat load overload factor calculation unit dynamically calculates the precooler heat load overload factor. The dynamic early warning triggering logic construction unit constructs dynamic early warning triggering logic to optimize the engine bleed air over-temperature early warning logic.

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