Method for flight test of civil high bypass ratio turbofan engine air starting
By acquiring flight test points and conducting corresponding start-up tests, the problem of insufficient verification of the in-flight start-up capability of civil high-bypass turbofan engines was solved, and the correction of the in-flight start-up envelope and optimization of the engine model were achieved, ensuring flight safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AECC COMML AIRCRAFT ENGINE CO LTD
- Filing Date
- 2024-11-27
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies lack effective methods to verify and evaluate the in-flight start-up capability and flight start-up performance of civil high-bypass turbofan engines, which affects flight safety.
A method for in-flight start-up flight test of a civil high-bypass turbofan engine is provided. By acquiring the flight test point, controlling the flight platform to fly to the test point, starter-assisted start, steady-state wind turbine start, and rapid wind turbine re-ignition start-up tests are conducted, and the in-flight start-up envelope is corrected based on the test results.
The altitude and speed tolerance requirements for in-flight starting were clarified, the engine's flight start capability was verified, the in-flight starting model was optimized, and the reliability and safety of engine starting under different flight conditions were ensured.
Smart Images
Figure CN122108615A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aircraft engine technology, and more specifically, to a method for in-flight start-up flight test of a civil high-bypass turbofan engine. Background Technology
[0002] Aircraft engines may experience in-flight engine failure due to various unforeseen factors during flight. The ability to successfully restart aircraft engines in the air is directly related to flight safety. China's Civil Aviation Administration of China (CAAC) airworthiness standard for transport category aircraft, CCAR-25, stipulates that there must be a means to restart any engine in flight, that altitude and airspeed envelopes for in-flight engine restart must be defined, and that each engine must have the capability to restart within these envelopes.
[0003] Before a high-bypass turbofan engine can be officially installed on an aircraft for certification flight tests, it needs to be installed on an aircraft platform for in-flight start-up flight tests to verify the engine's in-flight start-up capability, verify the rationality of the design of the altitude and speed envelope range and envelope boundaries for in-flight start-up, and verify and evaluate the engine's operating characteristics during in-flight start-up. However, there are currently no methods for verifying the in-flight start-up capability and flight start-up performance of civil high-bypass turbofan engines. Summary of the Invention
[0004] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.
[0005] The objectives of this invention include, for example, providing a method for in-flight start-up flight testing of a civil high-bypass turbofan engine, which can improve the shortcomings in the specific implementation of in-flight start-up capability verification and flight start-up performance testing of civil high-bypass turbofan engines.
[0006] The embodiments of the present invention can be implemented as follows:
[0007] An embodiment of the present invention provides a method for in-flight start-up flight test of a civil high-bypass turbofan engine, comprising:
[0008] Obtain the flight test point; control the flight platform to fly to the flight test point, where the allowable tolerance for flight altitude is ±100 meters and the allowable tolerance for Mach number is ±0.01; based on the flight test point, control the test engine to conduct starter-assisted start test, steady-state windmill start test, or rapid windmill re-ignition start test; based on the results of the starter-assisted start test, steady-state windmill start test, and rapid windmill re-ignition start test, correct the in-flight start envelope.
[0009] Optionally, the step of obtaining flight test points includes: obtaining typical flight test points for engine in-flight start-up based on the engine's in-flight start-up envelope and aircraft requirements, and using these as flight test points.
[0010] Optionally, the step of obtaining the flight test point includes: obtaining the boundary point on the air start envelope of the engine as the flight test point; and performing the step of controlling the test engine to perform starter-assisted start test, steady-state windmill start test or rapid windmill re-ignition start test based on the flight test point at least twice.
[0011] Optionally, the step of obtaining flight test points includes: selecting test points at equal speed intervals at each altitude within the air start envelope of the engine, with an altitude interval of 1500m and a Mach number interval of 0.05 to 0.1, based on the engine's air start envelope.
[0012] Optionally, the step of obtaining the flight test point includes: obtaining the flight test point based on the range of the engine's in-flight start-up safety island; wherein the range of the in-flight start-up safety island is located within the windmill's start-up envelope.
[0013] Optionally, the air starting envelope includes a starter motor auxiliary starting envelope and a windmill starting envelope.
[0014] Optionally, the step of controlling the test engine to perform starter-assisted start test, steady-state windmill start test, or rapid windmill re-ignition start test according to the flight test point includes: if the flight test point is a test point on or inside the starter-assisted start envelope, then perform a starter-assisted start test; if the flight test point is a test point on or inside the windmill start envelope, then perform a steady-state windmill start test and a rapid windmill re-ignition start test; if the flight test point is a test point within the air start safety island range, then perform a starter-assisted start test, a steady-state windmill start test, and a rapid windmill re-ignition start test.
[0015] Optionally, the steps of the starter-assisted starting test include: when the hot engine starting conditions are met, controlling the test engine starter ignition switch to the start position and the fuel control switch to the ON position to start the test engine; when the cold engine starting conditions are met, controlling the test engine to stop for 5 minutes, then controlling the test engine starter ignition switch to the start position and the fuel control switch to the ON position to start the test engine.
[0016] Optionally, the steps of the steady-state wind turbine start-up test include: when the hot engine start-up conditions are met, controlling the test engine start-up ignition switch to the normal position and the fuel control switch to the ON position to start the test engine; when the cold engine start-up conditions are met, controlling the test engine to stop for 5 minutes, then controlling the test engine start-up ignition switch to the normal position and the fuel control switch to the ON position to start the test engine.
[0017] Optionally, the steps of the rapid windmill restart test include: controlling the test engine to stop, and at different rapid windmill start-up times, controlling the test engine start-up ignition switch to the normal position and the fuel control switch to the ON position to start the test engine.
[0018] Optionally, the step of correcting the in-flight starting envelope based on the results of the starter motor-assisted starting test, the steady-state wind turbine starting test, and the rapid wind turbine re-ignition starting test includes:
[0019] If the test engine successfully starts to idle and the stable working time is less than the preset time, or if the test engine experiences overheating, surge, stall, excessive suspension or vibration, or if the starter motor assists in starting but the starter motor power is less than the power that the target device can actually provide, then the verification of the next flight test point will be carried out after repeating the verification a preset number of times.
[0020] The beneficial effects of the in-flight start-up flight test method for a civil high-bypass turbofan engine according to embodiments of the present invention include, for example:
[0021] A method for in-flight start-up flight test of a civil high-bypass turbofan engine includes: acquiring a flight test point; controlling the flight platform to fly to the flight test point, wherein the allowable tolerance for flight altitude is ±100 meters and the allowable tolerance for Mach number is ±0.01; according to the flight test point, controlling the test engine to conduct a starter-assisted start-up test, a steady-state windmill start-up test, or a rapid windmill re-ignition start-up test; and correcting the in-flight start-up envelope based on the results of the starter-assisted start-up test, the steady-state windmill start-up test, and the rapid windmill re-ignition start-up test.
[0022] Obtain flight test points. For each test point, within the allowable tolerance of ±100 meters for flight altitude and ±0.01 for Mach number, conduct starter motor assisted start test, steady-state windmill start test, or rapid windmill re-ignition start test to clarify the allowable tolerance requirements for altitude and speed for in-flight start test flights and to determine the in-flight start envelope. Attached Figure Description
[0023] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.
[0024] Figure 1 A flowchart illustrating the in-flight start-up flight test method for a civil high-bypass turbofan engine provided in an embodiment of the present invention;
[0025] Figure 2 An embodiment of the selection of flight test points in the in-flight start-up flight test method for a civil high-bypass turbofan engine provided by the present invention;
[0026] Figure 3 A flowchart of an in-flight start-up flight test method for a civil high-bypass turbofan engine provided in an embodiment of the present invention. Detailed Implementation
[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.
[0028] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," "outer," or "vertical" appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, and does not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0029] At the same time, it should be noted that the terms "first" and "second" are used only for distinguishing descriptions and should not be interpreted as indicating or implying relative importance.
[0030] In the description of this invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0031] The following is combined with Figures 1 to 3 The in-flight start-up flight test method for a civil high-bypass turbofan engine provided in this embodiment is described in detail.
[0032] Please refer to Figure 1 and Figure 3 This embodiment provides a method for in-flight start-up flight test of a civil high-bypass turbofan engine, including:
[0033] Step S1: Obtain the flight test point;
[0034] Step S2: Control the flight platform to fly to the flight test point, wherein the allowable tolerance for flight altitude is ±100 meters and the allowable tolerance for Mach number is ±0.01.
[0035] Step S3: Based on the flight test point, control the test engine to perform a starter-assisted start test, a steady-state windmill start test, or a rapid windmill re-ignition start test;
[0036] Step S4: Based on the results of the starter motor-assisted starting test, steady-state wind turbine starting test, and rapid wind turbine re-ignition starting test, the in-flight starting envelope is corrected.
[0037] It should be noted that a Civil High Bypass Ratio Turbofan Engine is a turbofan engine with a bypass ratio of 4 or higher that is installed in civil aircraft. Air-start for aero-engine: The air-start capability of an aero-engine is its ability to restart in the air after the engine has been shut down. Air-start includes starter-assisted starting and windmill starting. Windmill starting includes rapid windmill restart and steady-state windmill starting. Starter-assisted starting refers to the starting procedure where the starter motor drives the engine rotor after the engine has stopped. Windmill starting refers to the in-flight starting of the engine without relying on the starter motor, using the impact of the windmill's rotation speed to drive the engine. Steady-state windmill starting refers to the process where, after the engine has stopped, it relies on the energy of the incoming flow (such as aerodynamics) to reach a certain windmill speed, and then completes the ignition and restart process without the need for a starter motor. Rapid windmill restart refers to the process where, after the engine has stopped, it uses the windmill effect to reach a certain speed within a short period of time (such as 10 seconds, 15 seconds, 20 seconds, and 30 seconds) after the engine has stopped, and then immediately initiates the ignition and restart process.
[0038] Obtain flight test points. For each test point, within a tolerance range of ±100 meters for flight altitude and ±0.01 for Mach number, conduct starter motor assisted start tests, steady-state windmill start tests, or rapid windmill re-ignition start tests. Clarify the tolerance requirements for altitude and speed during in-flight start-up test flights, determine the in-flight start-up envelope, verify the engine's start-up capability in flight conditions, benchmark against requirements, and verify the degree to which the engine meets the requirements for on-board flight conditions; verify the applicability of the start-up law in in-flight conditions and achieve condition-based optimization; calibrate and revise the engine model, verify the engine model correction method, and optimize the in-flight start-up model.
[0039] In this embodiment, the air starting envelope includes the starter motor auxiliary starting envelope and the windmill starting envelope.
[0040] In this embodiment, step S1, the step of obtaining flight test points, includes: step S11, obtaining typical flight test points for engine in-flight start-up based on the engine's in-flight start-up envelope and aircraft requirements, as flight test points.
[0041] Determine the required engine in-flight start envelope for the aircraft. Based on the aircraft's requirements, select typical in-flight start flight test points to meet the requirements for verifying in-flight start capability. Flight start tests must be conducted at these typical test points. Aircraft requirements are primarily derived from the manufacturer's specifications.
[0042] For example, the engine in-flight start envelope, such as Figure 2As shown, the Mach number range is 0.2–0.6, and the altitude range is 0–6 km. The Mach number range for the starter motor auxiliary starting envelope is 0.2–0.4, and the Mach number range for the windmill starting envelope is 0.4–0.6. Two typical in-flight starting points are proposed: 0.5 Mach, 5 km and 0.55 Mach, 5.5 km. These two points must be designated as test points.
[0043] In this embodiment, step S1, the step of obtaining the flight test point, includes: step S12, obtaining the boundary point on the air start envelope of the engine as the flight test point; and executing the steps of controlling the test engine to perform starter-assisted start test, steady-state windmill start test or rapid windmill re-ignition start test more than twice based on the flight test point.
[0044] Typical points on the boundaries of the in-flight starting capability envelope are selected to meet the verification requirements of in-flight starting capability. To ensure the success rate of engine in-flight starting and avoid accidental factors, boundary points, especially those at low speeds, are subjected to at least two in-flight starting tests. Boundary points on the in-flight starting envelope can be selected from critical points or inflection points.
[0045] For example, refer to Figure 2 Select test points on the boundary. For starter motor assisted starting, two starting tests need to be arranged for the test point with Ma=0.2; for windmill starting test point with Ma=0.4, two starting tests need to be arranged.
[0046] In this embodiment, step S1, the step of obtaining flight test points, includes: step S13, according to the engine's air start envelope, within the air start envelope, at flight altitude intervals of 1500m and Mach number intervals of 0.05 to 0.1, at each altitude with equal speed intervals, as flight test points.
[0047] Test points are selected within the in-flight starting envelope to record in-flight starting performance to meet model correction requirements. The altitude is generally spaced at 5000ft (1500m) intervals, and the Mach number intervals are 0.05 to 0.1 (or a certain value for calibration airspeed). Test points are selected at equal (or approximately equal) speed intervals at each altitude.
[0048] For example, refer to Figure 2 Test points are selected within the in-flight starting envelope to record in-flight starting performance to meet model correction requirements (blue dots).
[0049] In this embodiment, step S1, the step of obtaining the flight test point, includes: step S14, obtaining the flight test point according to the range of the engine's air start safety island; wherein, the range of the air start safety island is located within the wind turbine's starting envelope.
[0050] The in-flight start safety island is the area within the in-flight start envelope of an aircraft engine that allows the engine to safely complete an in-flight start. Within the safety island, even if there is a deviation in the engine fuel supply or a deviation in the engine's geometric stroke or angle, the engine can still successfully complete an in-flight start without overheating, stalling, surge, engine shutdown, or suspension.
[0051] The first step in engine flight testing is to test the engine's ability to start in the air within the safety island. This verifies that the engine can start successfully using various in-flight starting methods, such as starter-assisted cold start, hot start, windmill cold start, hot start, and rapid start, all within the safety island area.
[0052] Examples, such as Figure 2 As shown, the green area is the safety island. The selection logic for test points within the safety island is that the area located in the middle of the in-flight start envelope must include windmill start, and the altitude and speed range must have sufficient safety margin for the aircraft.
[0053] In this embodiment, step S3, which involves controlling the test engine to perform a starter-assisted start test, a steady-state windmill start test, or a rapid windmill re-ignition start test based on the flight test point, includes the following steps:
[0054] Step S31: If the flight test point is a test point on or inside the starter auxiliary starting envelope, then a starter auxiliary starting test shall be performed.
[0055] Step S32: If the flight test point is a test point on or inside the wind turbine starting envelope, then a steady-state wind turbine starting test and a fast wind turbine re-ignition starting test shall be conducted.
[0056] Step S33: If the test point is within the air start safety island range, then the starter motor assisted start test, steady-state windmill start test, and rapid windmill re-ignition start test shall be carried out.
[0057] Different start-up tests were conducted at different flight test sites.
[0058] In this embodiment, the steps of the starter-assisted starting test include: when the hot engine starting conditions are met, controlling the test engine starter ignition switch to the start position and the fuel control switch to the ON position to start the test engine; when the cold engine starting conditions are met, controlling the test engine to stop for 5 minutes, then controlling the test engine starter ignition switch to the start position and the fuel control switch to the ON position to start the test engine.
[0059] For the starter motor-assisted start test point, the start test shall be carried out after the cold and hot start temperature conditions are met. For starter motor-assisted start, the engine shall be stopped for 5 minutes (there is no time requirement for hot engine start), and after the cold and hot start temperature conditions are met, the test engine start ignition switch shall be turned to the start position and the fuel control switch shall be turned to the ON position, and the test engine shall be started.
[0060] In this embodiment, the steps of the steady-state wind turbine start-up test include: when the hot engine start-up conditions are met, controlling the test engine start-up ignition switch to the normal position and the fuel control switch to the ON position to start the test engine; when the cold engine start-up conditions are met, controlling the test engine to stop for 5 minutes, then controlling the test engine start-up ignition switch to the normal position and the fuel control switch to the ON position to start the test engine.
[0061] For the steady-state wind turbine start-up test, the start-up test shall be carried out after the cold and hot start-up temperature conditions are met. For steady-state wind turbine start-up, the engine shall be stopped for 5 minutes (there is no time requirement for hot engine start-up), and after the cold and hot start-up temperature conditions are met, the test engine start-up ignition switch shall be set to the normal position and the fuel control switch shall be set to the ON position to start the test engine.
[0062] In this embodiment, the steps of the rapid windmill restart test include: controlling the test engine to stop, and at different rapid windmill start-up times, controlling the test engine start-up ignition switch to the normal position and the fuel control switch to the ON position to start the test engine.
[0063] For rapid wind turbine restart, after the engine stops, it is restarted within different specified time intervals, typically 10, 15, 20, and 30 seconds. The test engine is started by placing the test engine start ignition switch in the normal position and the fuel control switch in the ON position. The rapid wind turbine restart times are 10, 15, 20, and 30 seconds.
[0064] Continuing from above, refer to Figure 3 The flight test point is obtained, and the flight platform is controlled to fly to the required flight altitude and speed. The allowable tolerance for flight altitude is ±100 meters, and the allowable tolerance for Mach number is ±0.01. After the test engine's thrust rod is placed in the idle range and stabilized for 3 minutes, the test engine's fuel control switch is turned off, and the test engine is shut down. Then, the test engine is shut down, and the non-test engines are adjusted to maintain the flight platform's altitude and speed. The allowable tolerance for flight altitude is ±100 meters, and the allowable tolerance for Mach number is ±0.01.
[0065] If a starter-assisted start test is required at the flight test site, determine if the hot start condition is met, then turn the ignition switch to START and the fuel control switch to ON to start the test engine; if the cold start condition is met after stopping, control the test engine to stop for 5 minutes, then turn the test engine ignition switch to START and the fuel control switch to ON to start the test engine.
[0066] If the starter motor-assisted starting test cannot be performed, then a rapid windmill restart start is performed. Set the rapid windmill starting time, control the test engine start ignition switch to NORM and the fuel control switch to ON, and start the test engine.
[0067] If a rapid restart cannot be performed, a steady-state restart should be performed to determine if a hot start is possible. If it is possible, the test engine start ignition switch should be set to NORM and the fuel control switch should be set to ON to start the test engine. If a hot start is not possible, after the engine has been stopped and the cold start conditions are met, the test engine start ignition switch should be set to NORM and the fuel control switch should be set to ON to start the test engine.
[0068] If the above start is successful, maintain the idle state in the air for 3 minutes. If this is achieved, the verification is successful; if not, repeat the above steps. If three starts fail, this flight test point ends, and the verification for the next test point begins. After the flight, based on the test results, modify the control laws and conduct another start test.
[0069] In this embodiment, step S4, which involves correcting the in-flight starting envelope based on the results of the starter motor-assisted starting test, the steady-state windmill starting test, and the rapid windmill re-ignition starting test, includes the following steps:
[0070] If the test engine successfully starts to idle and the stable working time is less than the preset time, or if the test engine experiences overheating, surge, stall, excessive suspension or vibration, or if the starter motor assists in starting but the starter motor power is less than the power that the target device can actually provide, then the verification of the next flight test point will be carried out after repeating the verification a preset number of times.
[0071] The validity assessment technique for flight tests requires that the aircraft platform's flight conditions, namely flight altitude and speed, meet the test requirements; the test engine successfully starts to idle and can operate stably; no adverse phenomena such as overheating, surge, stall, suspension, or excessive vibration occur during the test engine start-up process; overheating is the phenomenon where the temperature exceeds the limit value during engine start-up; surge is an abnormal operating condition vibration that occurs in a turbine compressor (also called a vane compressor) when the flow rate decreases to a certain level, which is a periodic oscillation of the medium in fluid machinery and its pipelines, and is a mechanical vibration caused by the periodic intake and exhaust of the medium; stall is a phenomenon that occurs during engine operation that cannot be controlled by human or non-human factors; suspension is the phenomenon where the engine speed rises slowly or even stops during the start-up process from a stationary state to idle; excessive vibration is vibration exceeding the limit; the test engine start-up time meets the requirements of the aircraft manufacturer; for starter-assisted start-up, the starter power does not exceed the value specified in the interface document for flight engine coordination, and the starting power used in the flight stand start-up test cannot exceed the power value that the target installation object can actually provide.
[0072] According to the in-flight start-up flight test method for a civil high-bypass turbofan engine provided in this embodiment, the working principle of the in-flight start-up flight test method for a civil high-bypass turbofan engine includes:
[0073] a. The aircraft platform flies to the required altitude and speed. These are the conditions for the test.
[0074] b. Place the positive thrust lever on the test engine throttle panel in the idle position and stabilize for 3-5 minutes. Then, turn the test engine fuel control switch to the OFF position to shut down the test engine. Shut down the test engine according to the prescribed procedure.
[0075] c. After the test engine is shut down, adjust the non-test engines to maintain the required altitude and speed for flight. Adjust the non-test engines to keep the flight platform under test conditions.
[0076] d. For starter motor-assisted starting, after the engine has been stopped for 5 minutes (there is no time requirement for hot engine starting) and the cold and hot starting temperature conditions are met, the test engine starter ignition switch is set to the start position and the fuel control switch is set to the ON position to start the test engine.
[0077] e. For steady-state wind turbine start-up, the engine should be stopped for 5 minutes (there is no time requirement for hot engine start-up), and after the cold and hot start-up temperature conditions are met, the test engine start-up ignition switch should be set to the normal position and the fuel control switch should be set to the ON position to start the test engine.
[0078] f. For rapid windmill restart, after the engine stops, start the test engine by turning the test engine start ignition switch to the normal position and the fuel control switch to the ON position within different specified time periods (generally 10 seconds, 15 seconds, 20 seconds and 30 seconds).
[0079] g. After the test engine starts successfully, maintain it at idle for 3 minutes to verify that the engine started successfully.
[0080] The in-flight start-up flight test method for a civil high-bypass turbofan engine provided in this embodiment has at least the following advantages:
[0081] Obtain flight test points. For each test point, within a tolerance range of ±100 meters for flight altitude and ±0.01 for Mach number, conduct starter motor assisted start tests, steady-state windmill start tests, or rapid windmill re-ignition start tests. Clarify the tolerance requirements for altitude and speed during in-flight start-up test flights, determine the in-flight start-up envelope, verify the engine's start-up capability in flight conditions, benchmark against requirements, verify the degree to which the engine meets the requirements for on-board flight conditions, verify the applicability of the start-up law in in-flight conditions, and achieve condition-based optimization. Verify and correct the engine model, verify the engine model correction method, and optimize the in-flight start-up model.
[0082] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for in-flight start-up flight test of a civilian high-bypass turbofan engine, characterized in that, include: Acquire flight test sites; Control the flight platform to fly to the flight test point, where the allowable tolerance for flight altitude is ±100 meters and the allowable tolerance for Mach number is ±0.
01. Based on the flight test points, control the test engine to conduct starter-assisted start test, steady-state windmill start test, or rapid windmill re-ignition start test; Based on the results of the starter motor-assisted starting test, steady-state windmill starting test, and rapid windmill re-ignition starting test, the in-flight starting envelope was corrected.
2. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 1, characterized in that, The steps for obtaining flight test points include: Based on the engine's in-flight start envelope and aircraft requirements, typical flight test points for engine in-flight start are obtained and used as flight test points.
3. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 1, characterized in that, The steps for obtaining flight test points include: Based on the engine's in-flight start-up envelope, obtain the boundary points on the in-flight start-up envelope as flight test points; The steps of controlling the test engine to perform starter-assisted start test, steady-state windmill start test, or rapid windmill re-ignition start test according to the flight test point are executed more than twice.
4. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 1, characterized in that, The steps for obtaining flight test points include: Based on the engine's in-flight start-up envelope, within the in-flight start-up envelope, at flight altitude intervals of 1500m and Mach number intervals of 0.05 to 0.1, test points are selected at equal speed intervals at each altitude as flight test points.
5. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 1, characterized in that, The steps for obtaining flight test points include: Based on the range of the engine's in-flight start-up safety island, obtain the flight test points; The air-start safety island is located within the windmill starting envelope.
6. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to any one of claims 2-5, characterized in that: The in-flight starting envelope includes the starter motor auxiliary starting envelope and the windmill starting envelope.
7. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 6, characterized in that, The steps for controlling the test engine to perform starter-assisted start test, steady-state windmill start test, or rapid windmill re-ignition start test according to the flight test point include: If the flight test point is a test point on or inside the starter motor's auxiliary starting envelope, then the starter motor's auxiliary starting test shall be conducted. If the flight test point is the boundary or inner side of the wind turbine starting envelope, then a steady-state wind turbine starting test and a rapid wind turbine re-ignition starting test will be conducted. For test sites within the air start safety island area, starter motor assisted start test, steady-state windmill start test, and rapid windmill re-ignition start test will be conducted.
8. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 7, characterized in that, The steps of the starter motor auxiliary starting test include: Under the condition that the hot engine start-up conditions are met, the test engine is started by setting the ignition switch to the start position and the fuel control switch to the ON position. Under the condition that the cold start conditions are met, control the test engine to stop for 5 minutes, then turn the test engine start ignition switch to the start position and the fuel control switch to the ON position to start the test engine.
9. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 7, characterized in that, The steps of the steady-state wind turbine start-up test include: Under the condition that the hot engine start-up conditions are met, the test engine is started by setting the start-up ignition switch to the normal position and the fuel control switch to the ON position. Under the condition that the cold start conditions are met, control the test engine to stop for 5 minutes, then turn the test engine start ignition switch to the normal position and the fuel control switch to the ON position, and start the test engine.
10. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 7, characterized in that, The steps of the rapid windmill re-ignition and restart test include: To start the test engine, at different rapid wind turbine start times, set the test engine start ignition switch to the normal position and the fuel control switch to the ON position.
11. The method for in-flight start-up flight test of a civil high-bypass turbofan engine according to claim 1, characterized in that, The step of correcting the in-flight starting envelope based on the results of the starter motor-assisted starting test, the steady-state windmill starting test, and the rapid windmill re-ignition starting test includes: If the test engine successfully starts to idle and the stable working time is less than the preset time, or if the test engine experiences overheating, surge, stall, excessive suspension or vibration, or if the starter motor assists in starting but the starter motor power is less than the power that the target device can actually provide, then the verification of the next flight test point will be carried out after repeating the verification a preset number of times.