Method for determining warm-up rotating speed of double-rotor aero-engine

Abstract

The invention provides a method for determining the warm-up rotating speed of a double-rotor aero-engine, and belongs to the technical field of aero-engines. The method comprises the steps that the maximum allowable thrust during engine warm-up is determined; determining a corresponding high-pressure conversion rotating speed based on the maximum allowable thrust when the engine is warmed up; the minimum exhaust temperature difference between the engine warm-up state and the take-off state is determined; an engine air inlet temperature threshold value is determined, when the engine air inlet temperature is smaller than the engine air inlet temperature threshold value, the high-pressure conversion rotating speed corresponding to the maximum allowable thrust during engine warming-up serves as the engine warming-up rotating speed, and when the engine air inlet temperature is larger than or equal to the engine air inlet temperature threshold value, the high-pressure conversion rotating speed corresponding to the maximum allowable thrust during engine warming-up serves as the engine warming-up rotating speed. And according to the maximum exhaust temperature and the minimum exhaust temperature difference of the engine at different air inlet temperatures, the exhaust temperature at the corresponding air inlet temperature is obtained, according to the exhaust temperature, the high-pressure conversion rotating speed is determined, and therefore the warm-up rotating speed of the engine at the different air inlet temperatures is obtained.

Description

Technical Field

[0001] This application belongs to the field of aero-engines, and particularly relates to a method for determining the warm-up speed of a dual-rotor aero-engine. Background Art

[0002] For most heat engines, after starting, they need to gradually reach their maximum power operating state to avoid damage to the mechanical structure caused by sudden cooling and heating, and to improve the life and reliability of the heat engine. An aero-engine has working characteristics of high temperature, high pressure, and high speed, with an extremely complex mechanical structure and high requirements for the clearance between components. Preheating the engine to its maximum state can make the rotor-stator clearance closer to the optimal range, improving the working characteristics such as takeoff thrust and stability of the engine. The engine warm-up design is the result of a comprehensive design balance of requirements such as engine performance, reliability, and life. For a dual-rotor aero-engine, warm-up is generally carried out at a fixed high-pressure physical speed. However, when the intake air temperature is low, the corrected speed of the engine increases, even approaching the corrected speed at the intermediate state of the engine. The thrust during warm-up increases, resulting in difficult braking of the aircraft and increased fuel consumption. For multi-engine aircraft, it is necessary to adopt the method of warming up one engine at a time, increasing the waiting time of the aircraft on the runway and affecting the takeoff efficiency of the aircraft; when the intake air temperature is high, the corrected speed of the engine decreases, and the temperature difference between the components during warm-up and the components at the takeoff state becomes larger, the thermal stress of the components increases, the life is reduced, and even the structural integrity of the engine is damaged, directly threatening flight safety. Summary of the Invention

[0003] The purpose of this application is to provide a method for determining the warm-up speed of a dual-rotor aero-engine to solve or alleviate at least one problem in the background art.

[0004] The technical solution of this application is: A method for determining the warm-up speed of a dual-rotor aero-engine, including:

[0005] Determine the maximum allowable thrust during engine warm-up;

[0006] Based on the maximum allowable thrust during engine warm-up, determine the corresponding high-pressure corrected speed;

[0007] Determine the minimum exhaust gas temperature difference between the engine warm-up state and the takeoff state;

[0008] Determine the engine intake air temperature threshold. When the engine intake air temperature is less than the engine intake air temperature threshold, use the high-pressure conversion speed corresponding to the maximum allowable thrust during engine warm-up as the warm-up speed. When the engine intake air temperature is greater than or equal to the engine intake air temperature threshold, obtain the exhaust gas temperature corresponding to the intake air temperature based on the maximum exhaust gas temperature at different engine intake air temperatures and the minimum exhaust gas temperature difference, and determine the high-pressure conversion speed according to the exhaust gas temperature, so as to obtain the warm-up speed of the engine at different intake air temperatures.

[0009] Preferably, the maximum allowable thrust during engine warm-up is obtained through theoretical calculation or engine installation test.

[0010] Preferably, the process of determining the corresponding high-pressure conversion speed based on the maximum allowable thrust during engine warm-up includes:

[0011] Obtain the relationship curve between the high-pressure conversion speed n 2r and the engine thrust F through ground tests;

[0012] Obtain the high-pressure conversion speed n NJ-MAX corresponding to the maximum allowable thrust F 2r,nj,max .

[0013] Preferably, the minimum exhaust gas temperature difference ΔT 6min between the engine warm-up state and the take-off state is the difference between the high-pressure conversion speed n 2r,nj,max corresponding to engine warm-up and the high-pressure conversion speed n 2r,max corresponding to take-off.

[0014] Preferably, the engine intake air temperature threshold is 0 to 20 degrees Celsius.

[0015] Preferably, the maximum exhaust gas temperature at different engine intake air temperatures, the minimum exhaust gas temperature difference, and the exhaust gas temperature corresponding to the intake air temperature satisfy:

[0016] T6 = T6 max -ΔT 6min

[0017] In the formula, T6 is the exhaust gas temperature corresponding to different engine intake air temperatures;

[0018] T6 max is the maximum exhaust gas temperature at different engine intake air temperatures;

[0019] ΔT 6min is the minimum exhaust gas temperature difference.

[0020] Preferably, the warm-up speed is the high-pressure physical speed, and the high-pressure physical speed and the high-pressure conversion speed satisfy:

[0021]

[0022] Wherein, n 2r is the high-pressure conversion speed;

[0023] n2 is the high-pressure physical speed;

[0024] T2 is the engine intake air temperature.

[0025] The warm-up speed determination method for a dual-rotor aeroengine provided by this application selects the same conversion speed as the warm-up speed when the intake air temperature is low, ensuring that the engine thrust during warm-up meets the aircraft braking requirements; when the intake air temperature is high, it selects the high-pressure conversion speed corresponding to the "equal temperature difference" as the warm-up speed, ensuring the warm-up effect and improving the takeoff thrust, service life, and reliability. It can solve problems such as difficult aircraft braking or increased stress on engine components caused by engine warm-up in different weather temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solutions provided by this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0027] Figure 1 It is a schematic diagram of the warm-up speed determination method for a dual-rotor aeroengine of this application.

[0028] Figure 2 It is a schematic diagram of the high-pressure conversion speed corresponding to the maximum allowable thrust during warm-up in an embodiment of this application.

[0029] Figure 3 It is a schematic diagram of the difference between the minimum exhaust gas temperature at takeoff state and the engine warm-up speed in an embodiment of this application.

[0030] Figure 4 It is a schematic diagram of the relationship between the engine intake air temperature and the exhaust gas temperature in an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the drawings in the embodiments of this application.

[0032] The most important factor affecting the warm-up effect of an aeroengine is the temperature difference between the warm-up state and the take-off state (usually the full afterburner state and the intermediate state) of the engine (mainly high-temperature components, such as turbine components). The greater the temperature difference, the greater the thermal stress of the components. Especially for components with a large heat capacity such as the engine turbine disk, the life damage is greater, and the performance and reliability of the engine will deteriorate. Based on the essence of the impact of warm-up on the engine life and considering the aircraft usage requirements, this application proposes a method for determining the warm-up speed of a dual-rotor aeroengine that balances the aircraft usage requirements with the engine performance, life, and reliability. The method includes the following steps:

[0033] S10. Determine the maximum allowable thrust during engine warm-up:

[0034] Obtain the maximum allowable thrust F that the aircraft can withstand during warm-up at a general airport through aircraft design data NJ-MAX . The value of this maximum allowable thrust can be obtained through theoretical calculation or through engine installation tests.

[0035] S20. Determine the corresponding high-pressure corrected speed according to the maximum allowable thrust during engine warm-up:

[0036] As Figure 2 shown is the relationship curve between the high-pressure corrected speed n 2r and the engine thrust F in an embodiment of this application. According to the ground test bench, the relationship curve between the high-pressure corrected speed n 2r and the engine thrust F can be obtained. Through this relationship curve, the high-pressure corrected speed n NJ-MAX corresponding to the maximum allowable thrust F during engine warm-up can be further obtained 2r,Nj,max .

[0037] S30. Determine the minimum exhaust gas temperature difference between the engine warm-up state and the take-off state:

[0038] The speed control law for the engine in the intermediate and above operating states is generally to control at a constant corrected speed to obtain the maximum thrust level when the engine inlet temperature is less than a certain engine inlet temperature (i.e., the engine inlet temperature threshold T 2x ), and to control according to the physical speed or exhaust gas temperature when it is greater than a certain engine inlet temperature. The corrected speed of the engine in the intermediate and above operating states decreases as the inlet temperature increases.

[0039] In this application, based on the relationship curve between the high-pressure corrected speed n 2r and the engine exhaust gas temperature T6, the minimum exhaust gas temperature difference between the engine warm-up state and the take-off state is determined. As Figure 3 shown, this minimum exhaust gas temperature difference ΔT 6min is the high-pressure corrected speed n corresponding to the engine during warm-up2r,nj,max The difference from the high-pressure conversion speed n corresponding to takeoff 2r,max .

[0040] S40. Determine the engine intake air temperature threshold. When the engine intake air temperature is less than the engine intake air temperature threshold, use the high-pressure conversion speed corresponding to the maximum allowable thrust during engine warm-up as the warm-up speed. When the engine intake air temperature is greater than or equal to the engine intake air temperature threshold, obtain the exhaust gas temperature corresponding to the intake air temperature according to the maximum exhaust gas temperature at different engine intake air temperatures and the minimum exhaust gas temperature difference, and determine the high-pressure conversion speed according to the exhaust gas temperature, so as to obtain the warm-up speed of the engine at different intake air temperatures.

[0041] In some embodiments of the present application, the engine intake air temperature threshold T 2x can be taken as 0°C to 20°C. Exemplarily, the engine intake air temperature threshold T of a certain type of engine 2x is taken as 15°C.

[0042] When the engine intake air temperature T2 is less than the engine intake air temperature threshold T 2x , warm up the engine at the high-pressure conversion speed n corresponding to the maximum allowable thrust during warm-up 2r,Nj,max ; when the engine intake air temperature T2 is greater than the engine intake air temperature threshold T 2x , as Figure 4 shown, the relationship curve between the engine intake air temperature and the exhaust gas temperature at different engine intake air temperatures can be obtained through engine ground tests. According to this relationship curve, the maximum exhaust gas temperature at different engine intake air temperatures can be obtained. Based on the obtained minimum exhaust gas temperature difference △T6 min and the maximum exhaust gas temperature T6 at different engine intake air temperatures max , the exhaust gas temperature T6 corresponding to the intake air temperature can be obtained. Among them, the exhaust gas temperature T6 = T6 max -△T6 min , and then according to Figure 3 the relationship curve between the high-pressure conversion speed n 2r and the engine exhaust gas temperature T6, query the corresponding high-pressure conversion speed n 2r , so as to obtain the warm-up speed corresponding to the atmospheric temperature.

[0043] Among them, the warm-up speed is usually the high-pressure physical speed n2, and its relationship with the high-pressure conversion speed n 2r is specifically as follows:

[0044] As shown in Table 1, it is the warm-up speed table of a certain type of engine in an embodiment of the present application.

[0045] Table 1 Relationship table between warm-up speed and intake air temperature

[0046] <![CDATA[Engine intake air temperature T2 (°C)]]> Warm-up speed ＜15 <![CDATA[N 2r = 85%]]> 15 <![CDATA[N2 = 85% <!-- 3 -->]]> 25 <![CDATA[N2 = 90%]]> 35 <![CDATA[N2 = 90%]]>

[0047] The warm-up speed determination method for the dual-rotor aeroengine provided by this application selects the same converted speed as the warm-up speed when the intake air temperature is low, ensuring that the engine thrust during warm-up meets the aircraft braking requirements; when the intake air temperature is high, it selects the high-pressure converted speed corresponding to the "equal temperature difference" as the warm-up speed, ensuring the warm-up effect and improving the takeoff thrust, service life and reliability. It can solve problems such as difficult aircraft braking or increased stress on engine components caused by engine warm-up in different weather temperature environments. This method is simple to implement, easy to improve and has wide adaptability.

[0048] As mentioned above, it is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for determining the warm-up speed of a dual-rotor aeroengine, characterized in that Including: Determine the maximum allowable thrust during engine warm-up; Determine the corresponding high-pressure corrected speed based on the maximum allowable thrust during engine warm-up; Determine the minimum exhaust gas temperature difference between the engine warm-up state and the take-off state; Determine the engine intake air temperature threshold. When the engine intake air temperature is less than the engine intake air temperature threshold, use the high-pressure corrected speed corresponding to the maximum allowable thrust during engine warm-up as the warm-up speed. When the engine intake air temperature is greater than or equal to the engine intake air temperature threshold, obtain the exhaust gas temperature at the corresponding intake air temperature according to the maximum exhaust gas temperature at different engine intake air temperatures and the minimum exhaust gas temperature difference, and determine the high-pressure corrected speed according to the exhaust gas temperature, so as to obtain the warm-up speed of the engine at different intake air temperatures.

2. The warm-up speed determination method for a dual-rotor aeroengine according to claim 1, characterized in that The maximum allowable thrust during engine warm-up is obtained through theoretical calculation or engine installation test.

3. The warm-up speed determination method for a dual-rotor aeroengine according to claim 2, wherein The process of determining the corresponding high-pressure corrected speed based on the maximum allowable thrust during engine warm-up includes: Obtain the high-pressure conversion speed n based on ground tests 2r The relationship curve between the engine thrust F; Obtain the maximum allowable thrust F during engine warm-up according to the relationship curve NJ-MAX The corresponding high-pressure corrected speed n 2r,nj,max .

4. The method for determining the warm-up speed of a dual-rotor aero-engine according to claim 3, wherein The minimum exhaust gas temperature difference ΔT between the engine warm-up state and the take-off state 6min is the difference between the high-pressure corrected speed n corresponding to engine warm-up 2r,nj,max and the high-pressure corrected speed n corresponding to take-off 2r,max .

5. The warm-up speed determination method for a dual-rotor aero-engine according to claim 4, characterized in that The engine intake air temperature threshold is 0 to 20 degrees Celsius.

6. The method for determining the warm-up speed of a dual-rotor aeroengine according to claim 5, wherein The maximum exhaust gas temperature at different engine intake air temperatures, the minimum exhaust gas temperature difference, and the exhaust gas temperature at the corresponding intake air temperature satisfy: T6 = T6 max -ΔT 6min Wherein, T6 is the exhaust gas temperature corresponding to different engine intake air temperatures; T6 max is the maximum exhaust temperature at different intake air temperatures of the engine; ΔT 6min is the minimum exhaust gas temperature difference.

7. The warm-up speed determination method for a dual-rotor aero-engine according to claim 6, wherein, The warm-up speed is the high-pressure physical speed, and the high-pressure physical speed and the high-pressure corrected speed satisfy: where n 2r is the high-voltage conversion speed; n2 is the high-pressure physical speed; T2 is the engine intake air temperature.

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