Method and device for determining starting power of aviation turbofan engine

Abstract

The invention belongs to the technical field of engine design, and particularly relates to a method and device for determining starting power of an aviation turbofan engine. The method comprises the steps that S1, the resistance torque MH of a high-pressure rotor of an engine is determined according to the high-pressure rotating speed n; s2, the torque MT generated by a turbine is determined according to the high-pressure rotating speed n; s3, engine acceleration torque Ma under different high-pressure rotating speeds n is calculated on the basis of the given rotating speed rising rate; s4, determining the torque MCT of the starter according to the resistance torque of the high-pressure rotor of the engine, the torque generated by the turbine and the acceleration torque of the engine; and S5, calculating the starting power NCT according to the torque of the starter. According to the method, more reasonable and scientific requirements are provided for the power characteristics of the starter, and the design accuracy of the starter is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of engine design, and in particular, relates to a method and device for determining the starting power of an aviation turbofan engine. Background Art

[0002] Starting an aircraft engine is the first step in the work. Starting generally requires the help of a starter to provide a certain amount of power to assist the engine in accelerating from zero speed to a certain speed. After the engine meets the fuel supply and ignition conditions, the engine is put into operation and provides the remaining power together with the starter, and stably accelerates to a slow speed.

[0003] At present, the evaluation is generally carried out according to engineering experience and the existing product capabilities of the starter, and there is a deviation between the evaluation results and the actual needs of aircraft engines. If the starter power is designed to be too large, the weight and volume of the starter will be too large; if it is designed to be too small, the engine will not be able to start stably. At the same time, due to the changes in the working characteristics of the starter and the engine itself in low temperature and high temperature environments, plateaus, etc., the starter is affected by the environment, and the insufficient output power leads to a long starting time, which may cause the engine to fail to start in severe cases. Summary of the invention

[0004] In order to solve the above problems, the present application provides a method and device for determining the starting power of an aviation turbofan engine to solve the problem of starter power selection in engine development.

[0005] The first aspect of the present application provides a method for determining the starting power of an aviation turbofan engine, which mainly includes:

[0006] Step S1: Determine the engine high-pressure rotor resistance torque M according to the high-pressure speed n H ;

[0007] Step S2: Determine the torque M generated by the turbine according to the high pressure speed n T ;

[0008] Step S3: Calculate the engine acceleration torque M at different high-pressure speeds n based on a given speed increase rate. a ;

[0009] Step S4: Determine the starter torque M according to the engine high-pressure rotor resistance torque, the torque generated by the turbine and the engine acceleration torque. CT ;

[0010] Step S5: Calculate the starting power N according to the starter torque CT .

[0011] Preferably, step S1 further comprises:

[0012] Step S11, obtaining multiple groups of fitting parameters given by the speed change rate of the engine during the shutdown process of the whole machine test, each group of fitting parameters includes the high-pressure speed and the corresponding engine high-pressure rotor resistance torque;

[0013] Step S12: Calculate the engine high pressure rotor resistance torque M according to the fitting parameters. H Fitting calculation is performed with the correction coefficient a between the square of the high pressure speed;

[0014] Step S13: Determine the engine high pressure rotor resistance torque M by the following formula: H :M H =a*n 2 .

[0015] Preferably, step S2 further includes using different formulas to calculate the torque M generated by the turbine for different starting stages. T ,in:

[0016] (1) When the high pressure speed n is between 0 and the ignition speed, M T =0;

[0017] (2) When the high-pressure speed n is between the ignition speed and the disengagement speed, M T =c1*n-c2;

[0018]

[0019] Among them, n ig is the ignition speed, n p The minimum speed at which the engine turbine work and compressor work are balanced;

[0020] (3) When the high-pressure speed n is between the disengagement speed and the slow speed, M T =c3*n-c4;

[0021]

[0022] Among them, n so is the disengagement speed, n mc Slow speed.

[0023] Preferably, in step S4, the starter torque M is determined by the following formula: CT :

[0024] M CT =M a -M T +M H .

[0025] Preferably, in step S5, the starting power N is calculated by the following formula: CT :

[0026]

[0027] Preferably, step S5 further includes:

[0028] Step S6: Convert the starting power to the actual power N under the current aircraft starting environment CT1 :

[0029] N CT1 =N CT *(P H / P0) / (T1 / 288.15) k ;

[0030] Among them, N CT is the starting power calculated at sea level under standard atmospheric conditions, T1 is the temperature of the current aircraft starting environment, P0 is the standard atmospheric pressure at sea level, P H is the atmospheric pressure at the altitude H where the aircraft starts, and k is the temperature conversion factor.

[0031] The second aspect of the present application provides a device for determining starting power of an aviation turbofan engine, which mainly includes:

[0032] The engine high-pressure rotor resistance torque determination module is used to determine the engine high-pressure rotor resistance torque M according to the high-pressure speed n H ;

[0033] The torque determination module generated by the turbine is used to determine the torque M generated by the turbine according to the high-pressure speed n T ;

[0034] The engine acceleration torque determination module is used to calculate the engine acceleration torque M at different high-pressure speeds n based on a given speed increase rate. a ;

[0035] The starter torque determination module is used to determine the starter torque M according to the engine high-pressure rotor resistance torque, the torque generated by the turbine and the engine acceleration torque. CT ;

[0036] Starting power determination module, used to calculate the starting power N according to the starter torque CT .

[0037] Preferably, the engine high-pressure rotor resistance torque determination module includes:

[0038] A parking test parameter acquisition unit, used to acquire multiple sets of fitting parameters given by the speed change rate of the whole machine test engine during the parking process, each set of fitting parameters includes a high-pressure speed and a corresponding engine high-pressure rotor resistance torque;

[0039] The correction coefficient fitting unit is used to adjust the engine high pressure rotor resistance torque M according to the fitting parameters. H Fitting calculation is performed with the correction coefficient a between the square of the high pressure speed;

[0040] The engine high-pressure rotor drag moment calculation unit is used to determine the engine high-pressure rotor drag moment M by the following formula H :M H =a*n 2 .

[0041] Preferably, the turbine torque determination module further includes using different formulas to calculate the turbine torque M for different starting stages. T ,in:

[0042] (1) When the high pressure speed n is between 0 and the ignition speed, M T =0;

[0043] (2) When the high-pressure speed n is between the ignition speed and the disengagement speed, M T =c1*n-c2;

[0044]

[0045] Among them, n ig is the ignition speed, n p The minimum speed at which the engine turbine work and compressor work are balanced;

[0046] (3) When the high-pressure speed n is between the disengagement speed and the slow speed, M T =c3*n-c4;

[0047]

[0048] Among them, n so is the disengagement speed, n mc Slow speed.

[0049] Preferably, the device further comprises:

[0050] The actual power conversion module is used to convert the starting power to the actual power N under the current aircraft starting environment CT1 :

[0051] N CT1 =N CT *(P H / P0) / (T1 / 288.15) k ;

[0052] Among them, N CTis the starting power calculated at sea level under standard atmospheric conditions, T1 is the temperature of the current aircraft starting environment, P0 is the standard atmospheric pressure at sea level, P H is the atmospheric pressure at the altitude H where the aircraft starts, and k is the temperature conversion factor.

[0053] This application can calculate the power required for the starter under different high-voltage speeds, clarify the starter power requirements when starting the engine under different conditions, put forward more reasonable and scientific requirements for the starter power characteristics, and improve the accuracy of starter design. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a flow chart of a preferred embodiment of the method for determining the starting power of an aviation turbofan engine of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0056] The first aspect of the present application provides a method for determining the starting power of an aviation turbofan engine, such as Figure 1 As shown, it mainly includes:

[0057] Step S1: Determine the engine high-pressure rotor resistance torque M according to the high-pressure speed n H .

[0058] In some optional implementations, step S1 further includes:

[0059] Step S11, obtaining multiple groups of fitting parameters given by the speed change rate of the engine during the shutdown process of the whole machine test, each group of fitting parameters includes the high-pressure speed and the corresponding engine high-pressure rotor resistance torque;

[0060] Step S12: Calculate the engine high pressure rotor resistance torque M according to the fitting parameters. H Fitting calculation is performed with the correction coefficient a between the square of the high pressure speed;

[0061] Step S13: Determine the engine high pressure rotor resistance torque M by the following formula: H :M H =a*n 2 .

[0062] In this embodiment, the high-pressure rotor resistance torque mainly includes the compressor resistance torque, the resistance caused by bearing friction, and the resistance generated by engine accessories. The compressor resistance torque depends on the air flow and compression work; the resistance caused by bearing friction and the resistance generated by engine accessories during the starting process cannot be quantitatively calculated. Therefore, according to experience, the relationship between the engine high-pressure rotor resistance torque and the high-pressure speed can be expressed as: M H =a*n 2 .

[0063] After the whole machine test is completed, the correction coefficient a can be obtained based on the speed change rate of the engine during the whole machine test. The stopping process is expressed by the following formula:

[0064]

[0065] Among them, J is the rotational inertia of the engine high-pressure rotor. Through the above formula, multiple sets of fitting parameters can be obtained, and the correction coefficient a can be calculated.

[0066] Step S2: Determine the torque M generated by the turbine according to the high pressure speed n T .

[0067] In some optional embodiments, step S2 further includes using different formulas to calculate the torque M generated by the turbine at different starting stages. T ,in:

[0068] (1) When the high pressure speed n is between 0 and the ignition speed, M T =0;

[0069] (2) When the high-pressure speed n is between the ignition speed and the disengagement speed, M T =c1*n-c2;

[0070]

[0071] Among them, n ig is the ignition speed, n p The minimum speed at which the engine turbine work and compressor work are balanced;

[0072] (3) When the high-pressure speed n is between the disengagement speed and the slow speed, M T =c3*n-c4;

[0073]

[0074] Among them, nso is the disengagement speed, n mc Slow speed.

[0075] In this embodiment, when the high-pressure speed n is within the range of the ignition speed to the disengagement speed, the torque generated by the turbine depends on the gas temperature before the turbine and the engine rotor speed. During the starting process, the turbine torque can be approximately regarded as a linear relationship, especially in the stage from the start of the turbine to the disengagement of the starter, the linear performance is good. Therefore, the turbine torque can be expressed as: M T =c1*n-c2. It should also be noted that the ignition speed n ig That is, the speed at which the main combustion chamber is ignited after fuel is supplied. This value is obtained by calculation or component test verification by the engine designer. It is the minimum speed n at which the engine turbine work and compressor work are balanced. p You can follow M T =M H The principle of theoretical calculation is obtained. When the high-pressure speed n is between the disengagement speed and the slow speed, the disengagement speed n so That is, the speed at which the engine starts and leaves the starter. This value is calculated by the engine designer; the slow speed n mc It can be obtained by calculation by the engine designer, when n = n mc hour,

[0076] Step S3: Calculate the engine acceleration torque M at different high-pressure speeds n based on a given speed increase rate. a .

[0077] In this step, the engine acceleration torque calculation formula is: Based on this, the required acceleration torque is calculated, and the engine speed rise rate from 0 speed to slow speed during the starting process It is calculated by the designer based on the design objectives and combined with the characteristics of the engine components. In addition, this application assumes that the engine maintains the same starting fuel supply law and the starting acceleration rise rate remains unchanged.

[0078] Step S4: According to the engine high pressure rotor resistance torque M H , the torque generated by the turbine M T and engine acceleration torque M a Determine the starter torque M CT .

[0079] Engine acceleration torque M a Depends on the engine high pressure rotor resistance torque M H , the torque generated by the turbine M T The starter provides torque M CT , where M CTis the starter torque transmitted to the engine shaft. Based on this, the present application can obtain the unknown starter torque M according to the three known variables: CT .

[0080] In some optional implementations, in step S4, the starter torque M is determined by the following formula: CT :

[0081] M CT =M a -M T +M H .

[0082] Step S5: Calculate the starting power N according to the starter torque CT .

[0083] In some optional implementations, in step S5, the starting power N is calculated by the following formula: CT :

[0084]

[0085] The present application obtains the starting power under standard atmospheric conditions at sea level (altitude 0 km, atmospheric temperature 15°C) by the above method. The starter power of the aircraft engine in high, low temperature and plateau environments is further obtained by conversion. Specifically, in some optional implementations, step S5 further includes:

[0086] Step S6: Convert the starting power to the actual power N under the current aircraft starting environment CT1 :

[0087] N CT1 =N CT *(P H / P0) / (T1 / 288.15) k ;

[0088] Among them, N CT is the starting power calculated at sea level under standard atmospheric conditions, T1 is the temperature of the current aircraft starting environment, P0 is the standard atmospheric pressure at sea level, P H is the atmospheric pressure at the altitude H where the aircraft starting environment is located, and k is the temperature conversion coefficient, which is related to the characteristics of different starters.

[0089] The second aspect of the present application provides an aviation turbofan engine starting power determination device corresponding to the above method, mainly comprising:

[0090] The engine high-pressure rotor resistance torque determination module is used to determine the engine high-pressure rotor resistance torque M according to the high-pressure speed n H ;

[0091] The torque determination module generated by the turbine is used to determine the torque M generated by the turbine according to the high-pressure speed n T ;

[0092] The engine acceleration torque determination module is used to calculate the engine acceleration torque M at different high-pressure speeds n based on a given speed increase rate. a ;

[0093] The starter torque determination module is used to determine the starter torque M according to the engine high-pressure rotor resistance torque, the torque generated by the turbine and the engine acceleration torque. CT ;

[0094] Starting power determination module, used to calculate the starting power N according to the starter torque CT .

[0095] In some optional implementations, the engine high-pressure rotor resistance torque determination module includes:

[0096] A parking test parameter acquisition unit, used to acquire multiple sets of fitting parameters given by the speed change rate of the whole machine test engine during the parking process, each set of fitting parameters includes a high-pressure speed and a corresponding engine high-pressure rotor resistance torque;

[0097] The correction coefficient fitting unit is used to adjust the engine high pressure rotor resistance torque M according to the fitting parameters. H Fitting calculation is performed with the correction coefficient a between the square of the high pressure speed;

[0098] The engine high-pressure rotor drag moment calculation unit is used to determine the engine high-pressure rotor drag moment M by the following formula H :M H =a*n 2 .

[0099] In some optional embodiments, the turbine torque determination module further includes using different formulas to calculate the turbine torque M for different starting stages. T ,in:

[0100] (1) When the high pressure speed n is between 0 and the ignition speed, M T =0;

[0101] (2) When the high-pressure speed n is between the ignition speed and the disengagement speed, M T =c1*n-c2;

[0102]

[0103] Among them, n ig is the ignition speed, n p The minimum speed at which the engine turbine work and compressor work are balanced;

[0104] (3) When the high-pressure speed n is between the disengagement speed and the slow speed, M T =c3*n-c4;

[0105]

[0106] Among them, n so is the disengagement speed, n mc Slow speed.

[0107] In some optional implementations, in the starter torque determination module, the starter torque M is determined by the following formula: CT :

[0108] M CT =M a -M T +M H .

[0109] In some optional implementations, in the starting power determination module, the starting power N is calculated by the following formula: CT :

[0110]

[0111] In some optional embodiments, the device further comprises:

[0112] The actual power conversion module is used to convert the starting power to the actual power N under the current aircraft starting environment CT1 :

[0113] N CT1 =N CT *(P H / P0) / (T1 / 288.15) k ;

[0114] Among them, N CT is the starting power calculated at sea level under standard atmospheric conditions, T1 is the temperature of the current aircraft starting environment, P0 is the standard atmospheric pressure at sea level, P H is the atmospheric pressure at the altitude H where the aircraft starts, and k is the temperature conversion factor.

[0115] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining the starting power of an aviation turbofan engine, characterized in that: include: Step S1: Determine the engine high-pressure rotor resistance torque M according to the high-pressure speed n H ; Step S2: Determine the torque M generated by the turbine according to the high pressure speed n T ; Step S3: Calculate the engine acceleration torque M at different high-pressure speeds n based on a given speed increase rate. a ; Step S4: Determine the starter torque M according to the engine high-pressure rotor resistance torque, the torque generated by the turbine and the engine acceleration torque. CT ; Step S5: Calculate the starting power N according to the starter torque CT .

2. The method for determining the starting power of an aviation turbofan engine according to claim 1, wherein: Step S1 further comprises: Step S11, obtaining multiple groups of fitting parameters given by the speed change rate of the engine during the shutdown process of the whole machine test, each group of fitting parameters includes the high-pressure speed and the corresponding engine high-pressure rotor resistance torque; Step S12: Calculate the engine high-pressure rotor resistance torque M according to the fitting parameters. H Fitting calculation is performed with the correction coefficient a between the square of the high pressure speed; Step S13: Determine the engine high pressure rotor resistance torque M by the following formula: H :M H =a*n 2 .

3. The method for determining the starting power of an aviation turbofan engine according to claim 2, wherein: Step S2 further includes using different formulas to calculate the torque M generated by the turbine for different starting stages. T ,in: (1) When the high pressure speed n is between 0 and the ignition speed, M T =0; (2) When the high-pressure speed n is between the ignition speed and the disengagement speed, M T =c1*n-c2; Among them, n ig is the ignition speed, n p The minimum speed at which the engine turbine work and compressor work are balanced; (3) When the high-pressure speed n is between the disengagement speed and the slow speed, M T =c3*n-c4; Among them, n so is the disengagement speed, n mc Slow speed.

4. The method for determining the starting power of an aviation turbofan engine according to claim 1, wherein: In step S4, the starter torque M is determined by the following formula: CT : M CT =M a -M T +M H 。 5. The method for determining the starting power of an aviation turbofan engine according to claim 1, characterized in that: In step S5, the starting power N is calculated by the following formula: CT :

6. The method for determining the starting power of an aviation turbofan engine according to claim 1, characterized in that: Step S5 further includes: Step S6: Convert the starting power to the actual power N under the current aircraft starting environment CT1 : N CT1 =N CT *(P H / P0) / (T1 / 288.15) k ; Among them, N CT is the starting power calculated at sea level under standard atmospheric conditions, T1 is the temperature of the current aircraft starting environment, P0 is the standard atmospheric pressure at sea level, P H is the atmospheric pressure at the altitude H where the aircraft starts, and k is the temperature conversion factor.

7. A device for determining starting power of an aviation turbofan engine, characterized in that: include: The engine high-pressure rotor resistance torque determination module is used to determine the engine high-pressure rotor resistance torque M according to the high-pressure speed n H ; The torque determination module generated by the turbine is used to determine the torque M generated by the turbine according to the high-pressure speed n T ; The engine acceleration torque determination module is used to calculate the engine acceleration torque M at different high-pressure speeds n based on a given speed increase rate. a ; The starter torque determination module is used to determine the starter torque M according to the engine high-pressure rotor resistance torque, the torque generated by the turbine and the engine acceleration torque. CT ; Starting power determination module, used to calculate the starting power N according to the starter torque CT .

8. The device for determining the starting power of an aviation turbofan engine according to claim 7, characterized in that: The engine high-pressure rotor resistance torque determination module comprises: A parking test parameter acquisition unit, used to acquire multiple sets of fitting parameters given by the speed change rate of the whole machine test engine during the parking process, each set of fitting parameters includes a high-pressure speed and a corresponding engine high-pressure rotor resistance torque; The correction coefficient fitting unit is used to adjust the engine high pressure rotor resistance torque M according to the fitting parameters. H Fitting calculation is performed with the correction coefficient a between the square of the high pressure speed; The engine high-pressure rotor drag moment calculation unit is used to determine the engine high-pressure rotor drag moment M by the following formula H :M H =a*n 2 .

9. The device for determining the starting power of an aviation turbofan engine according to claim 8, characterized in that: The turbine torque determination module further includes using different formulas to calculate the turbine torque M for different starting stages. T ,in: (1) When the high pressure speed n is between 0 and the ignition speed, M T =0; (2) When the high-pressure speed n is between the ignition speed and the disengagement speed, M T =c1*n-c2; Among them, n ig is the ignition speed, n p The minimum speed at which the engine turbine work and compressor work are balanced; (3) When the high-pressure speed n is between the disengagement speed and the slow speed, M T =c3*n-c4; Among them, n so is the disengagement speed, n mc Slow speed.

10. The device for determining the starting power of an aviation turbofan engine according to claim 7, characterized in that: The device further comprises: The actual power conversion module is used to convert the starting power to the actual power N under the current aircraft starting environment CT1 : N CT1 =N CT *(P H / P0) / (T1 / 288.15) k ; Among them, N CT is the starting power calculated at sea level under standard atmospheric conditions, T1 is the temperature of the current aircraft starting environment, P0 is the standard atmospheric pressure at sea level, P H is the atmospheric pressure at the altitude H where the aircraft starts, and k is the temperature conversion factor.

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