A method for anti-surge control in high Mach number flight state

Abstract

The present application belongs to the field of engine anti-surge control, specifically a method for anti-surge control in a high Mach number flight state, comprising first obtaining the aircraft's intake flow characteristic data and the engine's operating intake flow characteristic data, obtaining the aircraft's intake flow characteristic data, establishing the relationship between the intake duct converted flow and the intake Mach number of the corresponding aircraft model, and establishing the relationship between the engine's converted flow and the low-pressure converted speed; setting the converted air flow to establish the corresponding relationship between the Mach number and the engine's low-pressure converted speed to perform the anti-surge action; combining the converted speed at a high Mach number with the low-pressure converted speed for anti-surge design, which can avoid, when the engine is anti-surge in a high Mach number working state, a flow drop caused by a drop in state, resulting in a mismatch between the intake duct and the engine flow; ensuring effective exit after surge in a high Mach number state, avoiding unsuccessful anti-surge, resulting in mid-air parking, and causing flight accident symptoms.

Description

Technical Field

[0001] The present application belongs to the field of engine anti-surge control, and in particular relates to an anti-surge control method for high Mach number flight conditions. Background Art

[0002] Surge relief is a procedure performed after an engine surge event. Its primary function is to eliminate the unstable state caused by the surge and subsequently restore the engine to the specified throttle lever position according to the prescribed acceleration procedure. During this operation, the engine control system reduces the main combustion fuel flow to the minimum fuel flow required to maintain stable engine operation, i.e., the idling fuel flow. By reducing fuel flow and lowering engine operating conditions, the engine's stability margin is increased and instability is eliminated in conjunction with the nozzle and compressor guide vane movement.

[0003] When an aircraft is operating at high altitude and high Mach numbers, the engine typically operates at maximum speed. If surge occurs in this state, executing a surge reduction fuel cut will cause the engine speed to drop sharply, which in turn will cause a decrease in engine intake flow.

[0004] Currently, after surge occurs at a large Mach number, the anti-surge logic is the same as other states: according to the duration of the surge signal, periodic fuel cut is executed. If the surge signal persists, periodic fuel cut is continuously executed, causing the engine speed to continue to decrease, and in severe cases, it will be reduced to idle speed.

[0005] When the engine's performance degrades, the required intake airflow decreases. However, the aircraft is still operating at supersonic speeds, and the actual intake airflow exceeds the engine's required flow. This can cause intake surge, exacerbating the engine's surge depth and making it impossible to recover. In severe cases, overheating can occur, leading to an in-flight shutdown.

[0006] In order to solve the problem of aircraft surge handling in high-altitude and high-Mach number state, a surge relief and fuel supply control method is proposed to ensure that the engine surge relief execution exits the surge requirement while being compatible with the problem of matching the air flow of the inlet and the engine. Summary of the Invention

[0007] The purpose of this application is to provide a method for anti-surge control in a high Mach number flight state to solve or alleviate at least one problem in the background technology.

[0008] The technical solution of the present application is: a method for controlling the snoring in a high Mach number flight state, comprising:

[0009] Conduct aircraft flight tests to obtain aircraft inlet flow characteristic data, and establish the relationship between the inlet converted flow rate and the intake Mach number of the corresponding aircraft model based on the aircraft inlet flow characteristic data;

[0010] Conduct engine bench tests, collect engine intake flow characteristic data, and establish the relationship between engine converted flow and low-pressure converted speed;

[0011] Set the converted air flow rate, and establish the corresponding relationship between the Mach number and the low-pressure converted speed of the engine through the converted air flow rate. This corresponding relationship is used as the basis for the design of the intake flow rate under the working state of large Mach number. The expression is: n 1Rma =f(Ma,n 1R );where n 1Rma is the conversion speed at large Mach number, n 1R Convert the speed to low pressure;

[0012] Set the timer txc. After receiving the anti-gasping command, perform the anti-gasping action according to the correspondence between the Mach number and the low-pressure converted speed of the engine, and collect the data of the low-pressure converted speed at the same time. When the low-pressure converted speed is less than or equal to the converted speed under the large Mach number, stop cutting the oil.

[0013] Preferably, when performing the anti-gasping action, a rapid oil cut is executed, and the oil cut cycle setting is consistent with the oil cut state under Ma<1.0; at the same time, a stabilization action is performed on other fans and compressors except the inlet fan.

[0014] Preferably, when the panting relief instruction is received, the oil cutting is also stopped.

[0015] Preferably, the intake flow characteristic data of the engine operation can also be obtained through component testing.

[0016] Preferably, when the Mach number Ma is less than 1.0, the inlet duct converted flow rate remains unchanged; when the Mach number Ma is greater than 1.0, the inlet duct converted flow rate decreases linearly.

[0017] Preferably, as the low-pressure converted speed increases, the engine converted flow rate gradually increases.

[0018] The anti-surge control method for high Mach number flight state of the present application establishes a corresponding relationship between Mach number and low-pressure converted speed of the engine, and combines the converted speed at high Mach number with the low-pressure converted speed to perform anti-surge design. This can avoid the flow rate drop caused by the state drop when the engine is anti-surge in the high Mach number working state, resulting in a mismatch between the intake duct and the engine flow rate; it can ensure effective exit after surge in the high Mach number state, and avoid unsuccessful anti-surge, resulting in parking in the air, and causing flight accident symptoms. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0020] Figure 1 This is a schematic diagram of the overall process of this application;

[0021] Figure 2 This is a schematic diagram of the converted flow rate and Mach number characteristics of the inlet for this application;

[0022] Figure 3 This is a schematic diagram of the low-pressure converted speed and intake converted flow characteristics of the engine in this application. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] A method for controlling the snorkeling in high Mach number flight conditions, such as Figure 1 As shown, the following steps are included:

[0025] Step S100: Conduct an aircraft flight test to obtain the aircraft's intake flow characteristic data, and establish a relationship between the intake flow rate and intake Mach number of the corresponding aircraft model based on the aircraft's intake flow characteristic data; or directly collect the data from existing test data. The specific relationship is as follows: Figure 2 As shown, it represents the air flow corresponding to a certain Ma, expressed as W1R inlet = f(Ma). This flow is only related to Ma. It can be seen that when the Mach number Ma is small and is less than 1.0, the inlet converted flow remains unchanged; when the Mach number Ma is large and is greater than 1.0, the inlet converted flow decreases linearly.

[0026] Step S200: Perform an engine bench test to collect engine intake flow characteristic data and establish a relationship between engine conversion flow and low-pressure conversion speed; Figure 3 As shown, it can be seen that as the low-pressure converted speed increases, the engine converted flow rate gradually increases.

[0027] Step S300, setting the converted air flow rate, which is an intermediate parameter between the intake duct flow rate characteristic data and the intake flow rate characteristic data of the engine, and is calculated from the intake duct flow rate characteristic data and the intake flow rate characteristic data of the engine; establishing a corresponding relationship between the Mach number and the low-pressure converted speed of the engine by converting the air flow rate, and this corresponding relationship serves as the basis for designing the intake flow rate under the high Mach number working state, and the expression is: n 1Rma =f(Ma,n 1R ). Where n 1Rma is the conversion speed at large Mach number, n 1RThe flow rate range that can ensure stable operation of the engine at different speeds is determined by the design, and the intake flow characteristic data of the engine can also be obtained through component testing.

[0028] Step S400, when the engine is operating in a large Mach number state (Ma>1.0 state), the engine itself is operating in a maximum power or thrust state, and the conversion speed is controlled in a limited speed state according to the design rules. If anti-gassing is performed in this state, the set anti-gassing action will be executed. The current anti-gassing measures for engines include main fuel oil cut-off, which generally reduces the main fuel supply according to a fixed cycle. This action causes the engine conversion speed to decrease, and the required intake conversion flow rate to decrease. At this time, the intake duct flow characteristics are only related to the working Mach number, so the intake duct flow characteristics cannot be matched with the flow characteristics in a wide range from low to high engine speeds. Therefore, when the engine speed is lower than the required intake conversion flow rate, it will cause airflow pulsation in the intake duct, causing the surge of the engine that is performing anti-gassing to worsen further.

[0029] To avoid engine surge, the anti-surge action is performed based on the relationship between low-pressure converted speed and Mach number. The specific design is as follows:

[0030] a. Set the timer txc. After receiving the asthma relief command, perform the asthma relief action. Use the timer txc to control the timing start and perform the following actions:

[0031] 1) Execute fast oil cutting, and the oil cutting cycle setting is consistent with the oil cutting state under Ma<1.0;

[0032] 2) Perform stabilization actions such as guide vane adjustment and nozzle adjustment for other fans and compressors except the inlet fan;

[0033] 3) Obtain low-pressure converted speed data in real time and compare it with the converted speed at high Mach numbers.

[0034] b. Stop the oil cutting action when one of the following conditions is met:

[0035] 1) The asthma relief instruction ends;

[0036] 2) When the real-time measured n 1R ≤n 1Rma .

[0037] In summary, by establishing a corresponding relationship between the Mach number and the low-pressure converted speed of the engine, and coordinating the converted speed at high Mach numbers with the low-pressure converted speed for anti-surge design, it is possible to avoid a mismatch between the inlet and engine flow rates due to a drop in flow caused by a drop in state when the engine is anti-surge under high Mach number working conditions; it is possible to ensure effective exit after surge under high Mach number conditions, and avoid unsuccessful anti-surge conditions, resulting in parking in the air, and causing flight accident symptoms.

[0038] Finally, it should be noted that the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures can refer to common designs. In the absence of conflicts, the same embodiment and different embodiments of the present invention can be combined with each other.

[0039] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling the snorkeling in a high Mach number flight state, characterized in that: include: Conduct aircraft flight tests, collect aircraft inlet flow characteristic data, and establish the relationship between the inlet converted flow rate and the intake Mach number of the corresponding aircraft model based on the aircraft inlet flow characteristic data; Conduct engine bench tests, collect engine intake flow characteristic data, and establish the relationship between engine converted flow and low-pressure converted speed; Set the converted air flow rate, and establish the corresponding relationship between the Mach number and the low-pressure converted speed of the engine through the converted air flow rate. This corresponding relationship is used as the basis for the design of the intake flow rate under the working state of large Mach number. The expression is: n 1Rma =f(Ma,n 1R );where n 1Rma is the conversion speed at large Mach number, n 1R Convert the speed to low pressure; Set the timer txc. After receiving the anti-gasping command, perform the anti-gasping action according to the correspondence between the Mach number and the low-pressure converted speed of the engine, and collect the data of the low-pressure converted speed at the same time. When the low-pressure converted speed is less than or equal to the converted speed under the large Mach number, stop cutting the oil.

2. The method for controlling the snoring in high Mach number flight state according to claim 1, wherein: When performing the anti-gasping action, a rapid oil cut is executed, and the oil cut cycle setting is consistent with the oil cut state under Ma<1.0; at the same time, the other fans and compressors except the inlet fan are subjected to stabilization action.

3. The method for controlling the snoring in high Mach number flight state according to claim 1, wherein: When receiving the command to stop panting, the oil cutting will also be stopped.

4. The method for controlling the snoring in high Mach number flight state according to claim 1, wherein: The intake air flow characteristic data of the engine operation can also be obtained through component testing.

5. The method for controlling the snoring in high Mach number flight state according to claim 1, wherein: When the Mach number Ma is less than 1.0, the inlet converted flow rate remains unchanged; when the Mach number Ma is greater than 1.0, the inlet converted flow rate decreases linearly.

6. The method for controlling the snoring in high Mach number flight state according to claim 1, wherein: As the low-pressure converted speed increases, the engine converted flow rate gradually increases.

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