A method for determining a warm-up rotating speed of a dual-rotor aero-engine

Abstract

The application provides a method for determining a warm-up rotating speed of a dual-rotor aero-engine, and belongs to the technical field of aero-engines. The method comprises the following steps: determining a maximum allowable thrust when the engine is warmed up; determining a corresponding high-pressure conversion rotating speed based on the maximum allowable thrust when the engine is warmed up; determining a minimum exhaust temperature difference between an engine warm-up state and a take-off state; determining an engine intake air temperature threshold; when the engine intake air temperature is less than the engine intake air temperature threshold, taking the high-pressure conversion rotating speed corresponding to the maximum allowable thrust when the engine is warmed up as the warm-up rotating speed; when the engine intake air temperature is greater than or equal to the engine intake air temperature threshold, obtaining an exhaust temperature corresponding to the intake air temperature according to the maximum exhaust temperature of the engine under different intake air temperatures and the minimum exhaust temperature difference, and determining the high-pressure conversion rotating speed according to the exhaust temperature, so as to obtain the warm-up rotating speed of the engine under different intake air temperatures.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engines, and particularly relates to a method for determining a warm-up rotating speed of a dual-rotor aero-engine. BACKGROUND

[0002] For most heat engines, after starting, they need to gradually reach their maximum power state to avoid sudden cooling and heating damage to mechanical structures, and to improve the service life and reliability of the heat engine. The aero-engine has the working characteristics of high temperature, high pressure and high rotating speed, and the mechanical structure is extremely complex, and the matching gap between the machine parts is high. Reaching the maximum state after the engine is preheated can make the rotor and stator gap closer to the optimal range, and improve the take-off thrust, stability and other working characteristics of the engine. The engine warm-up design is the result of the comprehensive design balance of the performance, reliability and service life requirements of the engine. For a dual-rotor aero-engine, it is generally warmed up at a fixed high-pressure physical rotating speed, but when the intake air temperature is low, the engine's converted rotating speed increases, and even approaches the converted rotating speed of the engine in the intermediate state. The thrust during warm-up increases, which makes it difficult for the airplane to brake, and also increases fuel consumption. For a multi-engine airplane, it has to adopt the single-engine rotation warm-up mode, which increases the airplane's waiting time on the runway and affects the airplane's take-off efficiency. When the intake air temperature is high, the engine's converted rotating speed decreases, the temperature difference between the engine components during warm-up and the components in the take-off state becomes larger, the thermal stress of the components increases, the service life decreases, and even the structural integrity of the engine is damaged, which directly threatens flight safety. SUMMARY

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

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

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

[0006] determining the corresponding high-pressure converted rotating speed based on the maximum allowable thrust of the engine during warm-up;

[0007] determining the minimum exhaust temperature difference between the warm-up state and the take-off state of the engine;

[0008] determining an engine intake temperature threshold, when the engine intake temperature is less than the engine intake temperature threshold, taking the high pressure conversion speed corresponding to the maximum allowed thrust of the engine during engine warm-up as the warm-up speed, when the engine intake temperature is greater than or equal to the engine intake temperature threshold, obtaining the exhaust temperature corresponding to the intake temperature according to the maximum exhaust temperature of the engine under different intake temperatures and the minimum exhaust temperature difference, and determining the high pressure conversion speed according to the exhaust temperature, thereby obtaining the warm-up speed of the engine under different intake temperatures.

[0009] Preferably, the maximum allowed thrust of the engine 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 allowed thrust of the engine during engine warm-up comprises:

[0011] obtaining the high pressure conversion speed n according to the ground test 2r and the relationship curve between the engine thrust F;

[0012] obtaining the maximum allowed thrust F of the engine during engine warm-up according to the relationship curve NJ-MAX the corresponding high pressure conversion speed n 2r,nj,max .

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

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

[0015] Preferably, the maximum exhaust temperature of the engine under different intake temperatures, the minimum exhaust temperature difference and the exhaust temperature under the corresponding intake temperature satisfy:

[0016] T6 = T6 max - ΔT 6min

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

[0018] T6 max is the maximum exhaust temperature of the engine under different intake temperatures;

[0019] ΔT 6min is the minimum exhaust 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] In the formula, n 2r is the high-pressure conversion speed;

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

[0024] T2 is the engine intake temperature.

[0025] The method for determining the warm-up speed of the dual-rotor aero-engine provided in the application selects the same conversion speed as the warm-up speed when the intake temperature is low, so as to ensure that the engine thrust during warm-up meets the aircraft braking requirement; selects the high-pressure conversion speed corresponding to the "equal temperature difference" as the warm-up speed when the intake temperature is high, so as to ensure the warm-up effect and improve the take-off thrust, service life and reliability, and can solve the problems of aircraft braking difficulty or increased engine component stress caused by engine warm-up in different weather temperature environments. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions provided in the application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the application.

[0027] Figure 1 FIG. 1 is a schematic diagram of the method for determining the warm-up speed of the dual-rotor aero-engine of the application.

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

[0029] Figure 3 FIG. 3 is a schematic diagram of the engine warm-up speed and the minimum exhaust temperature difference in the take-off state of an embodiment of the application.

[0030] Figure 4 FIG. 4 is a schematic diagram of the relationship between the engine intake temperature and the exhaust temperature of an embodiment of the application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the application clearer, the technical solutions in the embodiments of the application will be described in more detail below with reference to the drawings of the embodiments of the application.

[0032] The most important factor affecting the effectiveness of aero-engine warm-up is the temperature difference between the engine in the warm-up state and the takeoff state (generally full afterburner or intermediate state) (mainly high-temperature components, such as turbine components). The greater the temperature difference, the greater the thermal stress on the components, especially for components with high heat capacity such as the turbine disk, leading to greater lifespan damage and decreased engine performance and reliability. Based on the fundamental impact of warm-up on engine lifespan and considering aircraft usage requirements, this application proposes a method for determining the warm-up speed of a dual-rotor aero-engine that balances aircraft usage requirements with engine performance, lifespan, and reliability. This method includes the following steps:

[0033] S10, Determine the maximum permissible thrust during engine warm-up:

[0034] By examining the aircraft design data, we can determine the maximum permissible thrust F that the aircraft can withstand during warm-up at a typical airport. NJ-MAX The maximum permissible thrust value can be obtained through theoretical calculations or based on engine installation tests.

[0035] S20, its corresponding high-pressure converted speed is determined based on the maximum permissible thrust when the engine is warmed up:

[0036] like Figure 2 The figure shown is a high-pressure converted speed n according to an embodiment of this application. 2r The relationship curve between the engine thrust F and the high-pressure equivalent speed n can be obtained from ground bench tests. 2r The relationship curve between the engine thrust F and the engine thrust can be used to further determine the maximum permissible thrust F during engine warm-up. NJ-MAX The corresponding high-pressure equivalent speed n 2r,Nj,max .

[0037] S30, determine the minimum exhaust temperature difference between engine warm-up and takeoff conditions:

[0038] The speed control principle for engines in intermediate and higher operating states is generally based on operating speeds below a certain engine intake air temperature (i.e., the engine intake air temperature threshold T). 2x When the engine is in the middle or higher operating state, the converted speed is controlled according to the same conversion speed to obtain the maximum thrust level. When the engine intake temperature is higher than a certain engine intake temperature, the physical speed or exhaust temperature is used for control. The converted speed of the engine in the middle and higher operating states decreases as the intake temperature increases.

[0039] In this application, the rotational speed n is calculated based on high pressure. 2r The relationship curve between engine exhaust temperature T6 and engine exhaust temperature determines the minimum exhaust temperature difference between the engine warm-up state and the takeoff state, such as... Figure 3 As shown, the minimum exhaust temperature difference ΔT 6min This refers to the high-pressure equivalent speed n when the engine is warmed up.2r,nj,max The equivalent rotational speed n at high pressure during takeoff 2r,max difference.

[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 converted speed corresponding to the maximum allowable thrust of the engine during 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 temperature at the corresponding intake air temperature based on the maximum exhaust temperature and the minimum exhaust temperature difference at different engine intake air temperatures. Determine the high-pressure converted speed based on the exhaust temperature to obtain the warm-up speed of the engine at different intake air temperatures.

[0041] In some embodiments of this application, the engine intake air temperature threshold T 2x The temperature can be taken as 0℃ to 20℃. For example, the engine intake air temperature threshold T for a certain type of engine... 2x The temperature was set at 15℃.

[0042] When the engine intake air temperature T2 is less than the engine intake air temperature threshold T 2x At that time, the engine is driven at the high-pressure equivalent speed n corresponding to the maximum permissible thrust during warm-up. 2r,Nj,max Warm up the engine; when the engine intake air temperature T2 is greater than the engine intake air temperature threshold T 2x At times, such as Figure 4 The curve shown represents the relationship between different intake and exhaust temperatures of the engine, which can be obtained through ground testing. Based on this curve, the maximum exhaust temperature under different intake temperatures can be calculated, and the minimum exhaust temperature difference ΔT6 can be determined. min And the maximum exhaust temperature T6 of the engine under different intake air temperatures. max The exhaust temperature T6 corresponding to the intake air temperature can be obtained, where the exhaust temperature T6 = T6 max -△T6 min And then according to Figure 3 High pressure converted speed n 2r The curve showing the relationship between engine exhaust temperature T6 and the corresponding high-pressure converted speed n can be obtained by consulting the curve. 2r This allows us to obtain the warm-up speed at the corresponding atmospheric temperature.

[0043] Among them, the warm-up speed is usually the high-voltage physical speed n2, which is related to the high-voltage converted speed n. 2r The specific relationships are as follows:

[0044] Table 1 shows the warm-up speed table of a certain type of engine in one embodiment of this application.

[0045] Table 1 Relationship between Warm-up Speed ​​and Intake Air Temperature

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

[0047] The double-rotor aero-engine warm-up rotating speed determination method provided by the application selects the same converted rotating speed as the warm-up rotating speed when the intake temperature is low, so as to ensure that the engine thrust during warm-up meets the aircraft braking requirement; selects the high-pressure converted rotating speed corresponding to the "equal temperature difference" as the warm-up rotating speed when the intake temperature is high, so as to ensure the warm-up effect, improve the take-off thrust, service life and reliability, and solve the problems of aircraft braking difficulty or increased stress of engine components caused by engine warm-up in different weather temperature environments. The method is simple to implement, easy to improve and widely adaptable.

[0048] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the 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 aero-engine, characterized in that, include: Determine the maximum permissible thrust during engine warm-up; The corresponding high-pressure converted speed is determined based on the maximum permissible thrust of the engine during warm-up. Determine the minimum exhaust temperature difference between the engine warm-up state and the takeoff state, where the engine speed n is calculated based on the high pressure. 2r The relationship curve between the engine exhaust temperature T6 and the high-pressure converted speed n during engine warm-up is obtained. 2r,nj,max The corresponding exhaust temperature and the high pressure at takeoff are converted to the rotational speed n. 2r,max The corresponding exhaust temperature, and the high-pressure converted speed n during engine warm-up. 2r,nj,max The corresponding exhaust temperature and the high pressure at takeoff are converted to the rotational speed n. 2r,max The corresponding difference in exhaust temperature is the minimum exhaust temperature difference; The engine intake air temperature threshold is determined. When the engine intake air temperature is less than the engine intake air temperature threshold, the high-pressure converted speed corresponding to the maximum allowable thrust during engine warm-up is used as the warm-up speed. When the engine intake air temperature is greater than or equal to the engine intake air temperature threshold, the exhaust temperature at the corresponding intake air temperature is obtained based on the maximum exhaust temperature and the minimum exhaust temperature difference at different engine intake air temperatures. The high-pressure converted speed is determined based on the exhaust temperature, thereby obtaining the warm-up speed of the engine at different intake air temperatures.

2. The method for determining the warm-up speed of a dual-rotor aero-engine as described in claim 1, characterized in that, The maximum permissible thrust of the engine during warm-up is obtained through theoretical calculations or engine installation tests.

3. The method for determining the warm-up speed of a dual-rotor aero-engine as described in claim 2, characterized in that, The process of determining the corresponding high-pressure converted speed based on the maximum permissible thrust of the engine during warm-up includes: The high-pressure converted rotational speed n was obtained from ground tests. 2r The relationship curve between the engine thrust F and the thrust F; The maximum permissible thrust F during engine warm-up is obtained from the aforementioned relationship curve. NJ-MAX The corresponding high-pressure equivalent speed n 2r,nj,max .

4. The method for determining the warm-up speed of a dual-rotor aero-engine as described in claim 3, characterized in that, The engine intake air temperature threshold is 0~20 degrees Celsius.

5. The method for determining the warm-up speed of a dual-rotor aero-engine as described in claim 4, characterized in that, The maximum exhaust temperature under different intake air temperatures, the minimum exhaust temperature difference, and the corresponding exhaust temperature under the intake air temperatures satisfy the following: T6=T6 max -ΔT 6min In the formula, T6 is the exhaust temperature corresponding to different intake air temperatures of the engine; T6 max This represents the maximum exhaust temperature of the engine under different intake air temperatures. ΔT 6min This represents the minimum exhaust temperature difference.

6. The method for determining the warm-up speed of a dual-rotor aero-engine as described in claim 5, characterized in that, The warm-up speed is the high-voltage physical speed, and the high-voltage physical speed and the high-voltage converted speed satisfy the following: In the formula, n 2r n1 is the converted speed under high pressure; n2 is the physical speed under high pressure; T2 is the engine intake air temperature.

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