Aero-engine slow-speed stable operation control method

Abstract

The application belongs to the field of aero-engine design and is a slow-speed stable working control method for an aero-engine. The backup slow-speed state steady working fuel consumption variation, the backup slow-speed control attenuation, the backup acceleration fuel supply control attenuation, the main pump acceleration fuel supply deviation under different fuel temperatures, the critical value of the acceleration fuel supply quantity affecting the steady speed, the influence of the inlet duct on the acceleration fuel supply and the slow-speed fuel consumption dispersion are obtained respectively, the deviation of the engine acceleration fuel supply compared with the steady fuel supply is calculated, and the relationship curve between the half-time acceleration and the atmospheric temperature is further obtained. The requirements of the indoor and outdoor fields are determined according to the relationship curve between the half-time acceleration and the atmospheric temperature. The influences of the mechanical system attenuation characteristics, the environmental temperature influence characteristics, the influence of the aircraft inlet duct total pressure loss, the interference between the main pump acceleration oil and the steady oil and other factors are considered, the current situation of single control of the engine mechanical hydraulic backup system is avoided, and reliable work in the whole life cycle is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aero-engine design, and particularly relates to a slow-speed stable working control method of an aero-engine. BACKGROUND

[0002] An aero-engine control system is mainly divided into a mechanical hydraulic control system, an analog control system, a full-authorization digital electronic control system and the like, and a full-authorization digital electronic control system with a mechanical hydraulic backup mainly adds backup control redundancy on the basis of the full-authorization digital electronic control system, and when the full-authorization digital electronic control system fails, the mechanical hydraulic backup system is used to ensure the basic task requirements such as safe return of an airplane.

[0003] In the prior art, the engine mechanical hydraulic backup system control is relatively single, and only controls the delivery process steady slow-speed rotating speed. Generally, the rotating speed range of the engine is regulated during delivery, and only the change within a certain use time range can be ensured, the mechanical system attenuation characteristics, the environmental temperature influence characteristics, the influence of the airplane inlet duct total pressure loss, the interference between the main pump accelerated oil and the steady oil and the like are not considered, the airplane installation characteristics cannot be matched, the influence of other interference factors cannot be considered, and with the increase of the use time, the backup slow-speed rotating speed cannot work stably, and the airplane is stopped until the rotating speed is reduced.

[0004] Therefore, how to ensure the stable working of the backup slow-speed rotating speed is a problem to be solved. SUMMARY

[0005] The application aims to provide a slow-speed stable working control method of an aero-engine, so as to solve the problem that the backup slow-speed rotating speed cannot work stably with the increase of the use time in the prior art.

[0006] The technical scheme of the application is a slow-speed stable working control method of an aero-engine, comprising the following steps.

[0007] A backup slow-speed state steady working oil requirement change amount, a backup slow-speed control attenuation amount, a backup accelerated oil supply control attenuation amount, a main pump accelerated oil supply deviation amount under different fuel temperatures, a critical value of an accelerated oil supply amount influencing a steady rotating speed, an influence amount of an inlet duct on the accelerated oil supply and a slow-speed oil requirement dispersion degree are respectively obtained, and a deviation amount of the accelerated oil supply compared with the steady oil supply is calculated.

[0008] The deviation amount of the accelerated oil supply compared with the steady oil supply is converted to an accelerated performance requirement, and a relationship curve of a half-time acceleration and an atmospheric temperature is further obtained.

[0009] According to the upper and lower limit requirements of the half-acceleration time and the atmospheric temperature relationship curve, the factory requirements are determined according to the upper and lower limit requirements of the acceleration time, the backup slow-speed rotating speed inspection is carried out, the backup acceleration time requirement is set, which is used as the field requirement, and the backup slow-speed stable working control is carried out according to the factory requirements and the field requirements.

[0010] Preferably, the backup slow-speed state steady working oil consumption change amount is obtained by evaluating the backup slow-speed oil consumption WfR through the long test engine and the engine out-of-factory and out-of-life return factory, and through data statistics evaluation;

[0011] The backup slow-speed control attenuation amount is obtained by comparing the factory data through the main pump long test data or the main pump accessory tester performance recording carried out with the engine long test or the engine out-of-life return factory;

[0012] The backup slow-speed control attenuation amount is obtained by comparing the factory data through the main pump long test data or the main pump accessory tester performance recording carried out with the engine long test or the engine out-of-life return factory;

[0013] The main pump acceleration oil supply bias amount under different fuel temperatures is obtained through the test verification of the main pump tester combined with different fuel temperatures;

[0014] The critical value of the acceleration oil supply affecting the steady rotating speed control is obtained by gradually reducing the main pump acceleration oil supply amount and carrying out performance recording through the main pump tester test verification;

[0015] The influence amount of the intake passage on the acceleration oil supply is obtained by comparing the difference between the (acceleration oil supply amount-steady oil supply amount) / steady oil supply amount at the factory and the (acceleration oil supply amount-steady oil supply amount) / steady oil supply amount after installation;

[0016] The slow-speed oil consumption dispersion degree is obtained by evaluating the slow-speed oil consumption dispersion degree of different engines.

[0017] Preferably, after obtaining the deviation amount of the engine acceleration oil supply compared with the steady oil supply, the engine factory acceleration inspection data is corrected to the standard atmospheric condition, and the corresponding relationship between the half-acceleration time and the acceleration oil relative increase amount is obtained through statistics, and the relationship curve between the half-acceleration time and the atmospheric temperature is obtained through the least square method data fitting.

[0018] Preferably, after obtaining the deviation amount of the engine acceleration oil supply compared with the steady oil supply, the acceleration verification of different acceleration oil supply coefficients is carried out at a set atmospheric temperature, different acceleration oil relative increase amounts are obtained, the acceleration upper limit under different acceleration oil supply acceleration coefficients is determined respectively according to the pre-reserved range under the engine installation condition without abnormal conditions, and the relationship curve between the half-acceleration time and the atmospheric temperature is obtained by respectively statistically obtaining the half-acceleration time under different atmospheric temperatures.

[0019] An aero-engine slow-speed stable working control method provided by the application obtains the deviation of the engine accelerating oil supply compared with the steady oil supply by calculating the deviation of the engine accelerating oil supply compared with the steady oil supply through obtaining the backup slow-speed state steady working oil requirement change amount, the backup slow-speed control attenuation amount, the backup accelerating oil supply control attenuation amount, the main pump accelerating oil supply deviation amount under different fuel temperatures, the critical value of the accelerating oil supply amount affecting the steady rotating speed, the influence amount of the air inlet on the accelerating oil supply and the slow-speed oil requirement dispersion, and further obtains the relationship curve between the half accelerating time and the atmospheric temperature; the requirements of the internal and external fields are determined according to the relationship curve between the half accelerating time and the atmospheric temperature. The design of the compatible product capacity is realized by using the engineering method; the influences of the mechanical system attenuation characteristics, the environmental temperature influence characteristics, the influence of the air inlet total pressure loss, the interference between the main pump accelerating oil and the steady oil and other factors are considered, the single control status of the engine mechanical hydraulic backup system is avoided, and the reliable working in the whole life cycle is realized. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions provided by the application, the following will briefly introduce the drawings. Obviously, the drawings described below are only some embodiments of the application.

[0021] Figure 1 It is a whole process schematic diagram of the application;

[0022] Figure 2 It is a slow-speed steady fuel flow distribution schematic diagram of different engines of the application;

[0023] Figure 3 It is a relationship schematic diagram of the accelerating oil relative increase and the half accelerating of different engines of the application;

[0024] Figure 4 It is a relationship schematic diagram of the atmospheric temperature and the half accelerating of the application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the application clearer, the following will combine the drawings in the embodiments of the application to make the technical solutions in the embodiments of the application more detailed.

[0026] An aero-engine slow-speed stable working control method, as shown in Figure 1 includes the following steps:

[0027] Step S100, respectively obtaining the backup slow-speed state steady working oil requirement change amount, the backup slow-speed control attenuation amount, the backup accelerating oil supply control attenuation amount, the main pump accelerating oil supply deviation amount under different fuel temperatures, the critical value of the accelerating oil supply amount affecting the steady rotating speed, the influence amount of the air inlet on the accelerating oil supply and the slow-speed oil requirement dispersion, calculating the deviation of the engine accelerating oil supply compared with the steady oil supply.

[0028] Backup slow speed drop is mainly due to the steady state fuel flow is continuously affected by external factors to reduce the engine oil supply to maintain its slow speed, for this kind of situation, combined with Figure 2 , first to backup slow speed drop received external factors affecting the analysis:

[0029] 1) backup slow state steady working oil consumption changes. Mainly to analyze whether there is performance attenuation, resulting in the increase in the use of time, in order to maintain the same slow speed, the steady state fuel supply of the engine increases, can be obtained by long test engine and use to life engine factory and life return to the factory recording slow speed WfR, data statistics evaluation can obtain data, generally less impact can be ignored.

[0030] 2) backup slow control attenuation. Mechanical hydraulic control mode will exist with the increase of the use of time, mechanical system structure attenuation changes, so you need to analyze the main pump long time use data, statistics slow speed reduction value, can be statistical main pump long test data or with the engine long test or to life return to the factory to carry out main pump accessory tester performance recording comparison of factory data, verified the impact of slow speed is 1.4%.

[0031] 3) backup acceleration fuel control attenuation. With the increase of the use of time, mechanical system acceleration fuel control also exists, so you need to analyze the main pump long time use data, the same is to main pump long test data or with the engine long test or to life return to the factory to carry out main pump accessory tester performance recording comparison of factory data, statistics main pump acceleration fuel control attenuation value, attenuation value is about 3.0% verified.

[0032] 4) main pump internal acceleration fuel supply capacity is insufficient to correct the fuel temperature modifier. In the main pump tester, combined with the main pump test at different fuel temperature, the main pump acceleration fuel deviation is about 1.6% under different fuel temperature.

[0033] 5) main pump acceleration oil interference slow control. When the acceleration line and steady line close, the acceleration valve will gradually open, at this time the upper chamber pressure of the servo piston decreases, the speed drops. Main pump tester test verification method is to gradually reduce the main pump acceleration fuel quantity performance recording, when (acceleration fuel quantity-steady state fuel quantity) / steady state fuel quantity is 8.0%, the acceleration fuel begins to obviously affect the control of steady state speed, so that the slow speed reduces.

[0034] 6) Inlet duct influence. The factors such as the increase of protective net in front of the inlet duct, the inlet loss, the power extraction value, the altitude and the wind speed and direction of the airport, etc. will cause the decrease of the total pressure at the engine inlet, which will affect P31, and then the acceleration fuel supply controlled by the oil-gas ratio will decrease. The method is to compare the (acceleration fuel supply - steady-state fuel supply) / steady-state fuel supply at the factory and the (acceleration fuel supply - steady-state fuel supply) / steady-state fuel supply after installation, and obtain the difference. It is verified that the inlet loss after installation will affect the acceleration fuel supply of the main pump by about 5.0%.

[0035] Considering the above-mentioned mechanical and hydraulic system influencing factors, the acceleration fuel supply will gradually decrease with use, and will approach the steady-state fuel supply, thereby interfering with the steady-state fuel supply. Considering the product dispersion of the mechanical system, the dispersion of the slow-speed steady-state fuel requirement of different engines is evaluated, and the dispersion of the slow-speed fuel requirement is about 15%.

[0036] The deviation of the engine acceleration fuel supply compared with the steady-state fuel supply is:

[0037] 1.4% + 3.0% + 1.6% + 8.0% + 5.0% + 15% = 34%.

[0038] Only the deviation is converted to the acceleration performance requirement, it can be ensured that the acceleration fuel supply will not interfere with the steady-state fuel supply.

[0039] Step S200, the deviation of the acceleration fuel supply compared with the steady-state fuel supply is converted to the acceleration performance requirement, and the relationship curve of the half-time acceleration and the atmospheric temperature is further obtained;

[0040] Considering the superposition of various influencing factors, in order to ensure that the backup slow-speed of the engine can work stably, after the minimization analysis, the relative increase of the acceleration fuel corresponding to the deviation of the acceleration fuel supply compared with the steady-state fuel supply is obtained, that is, 34%.

[0041] In order to avoid the influence of different acceleration fuel supply rules of the engine, the first measure is to select a speed range from the slow-speed to a speed close to the slow-speed to evaluate the half-time acceleration performance, for example, from the slow-speed to n2R = 85%; the second measure is to design the acceleration fuel supply of the engine according to the given fuel supply rule, and to adopt the debugging method of enlarging and reducing the acceleration fuel supply by the whole proportion coefficient during the debugging process. The above-mentioned method can effectively ensure the influence of the relative increase of the acceleration fuel between different engines.

[0042] Method one for converting the deviation of the acceleration fuel supply compared with the steady-state fuel supply to the acceleration requirement:

[0043] After the engine factory acceleration performance check data is corrected to the standard atmospheric conditions, the corresponding relationship between the half-time acceleration and the relative increase of the acceleration fuel is obtained, such as Figure 3, two straight lines in the figure represent different engine models, and the relationship curve between half-time acceleration time and atmospheric temperature is obtained after least square data fitting. According to statistics, the half-time acceleration time of a certain type of engine is corrected to the standard atmospheric condition.

[0044] Method two for converting the deviation amount of acceleration fuel supply compared with steady-state fuel supply to acceleration requirement:

[0045] By carrying out acceleration verification of different acceleration fuel supply coefficients at a set atmospheric temperature, different relative increase amounts of acceleration oil (such as A-F) are obtained (for example, one state point is verified for every 0.1s of acceptable minimum acceleration time granularity; or every 1% acceleration fuel supply adjustment step); for different acceleration oil relative increase amounts C=34%, the upper limit of acceleration under different acceleration fuel supply coefficients is determined respectively through the engine installation condition under the condition of no abnormal situation, that is, the engine stability margin; considering that the acceleration performance is different with different atmospheric temperatures, the relationship curve between half-time acceleration time and atmospheric temperature is obtained by respectively counting the half-time acceleration time under different atmospheric temperatures, as shown in Figure 4 The upper straight line in the figure is the upper limit of half-time acceleration time, and the lower straight line is the lower limit of half-time acceleration time.

[0046] Step S300, determine the upper and lower limits of half-time acceleration time according to the relationship curve between half-time acceleration time and atmospheric temperature, determine the factory requirement according to the upper and lower limits of acceleration time, perform backup slow-speed speed check, set backup acceleration time requirement, as field requirement, perform backup slow-speed stable work control according to factory requirement and field requirement.

[0047] Factory requirement: for the determined upper and lower limits of half-time acceleration time, it can be used as factory requirement, in addition, for the slow-speed speed (72±2)%, the control can be appropriately tightened, the requirement range is changed to (72±1)%, to avoid the deviation of acceleration fuel supply rule from the design state.

[0048] Field requirement: increase the check of backup slow-speed speed, require within the range of (72±2)% speed; increase the backup acceleration time requirement in the field.

[0049] The application obtains the deviation of the engine acceleration oil supply compared with the steady state oil supply by respectively acquiring the backup slow vehicle state steady state working oil consumption change amount, the backup slow vehicle control attenuation amount, the backup acceleration oil supply control attenuation amount, the main pump acceleration oil supply deviation amount under different fuel temperatures, the critical value of the acceleration oil supply amount affecting the steady state rotating speed, the influence amount of the air inlet on the acceleration oil supply and the slow vehicle oil consumption dispersion, and further obtains the relationship curve between the half acceleration time and the atmospheric temperature; the requirements of the internal and external fields are determined according to the relationship curve between the half acceleration time and the atmospheric temperature. The engineering method is used to realize the design of the compatible product capacity; the influences of the mechanical system attenuation characteristics, the environmental temperature influence characteristics, the influence of the aircraft air inlet total pressure loss, the interference between the main pump acceleration oil and the steady state oil and other factors are considered, the single engine mechanical hydraulic backup system control status is avoided, the reliable work in the whole life cycle is realized, the engineering application is strong, the method based on data statistics and the like can be realized, the unstable slow vehicle rotating speed work of the backup in the external field use process can be avoided through the internal and external field comprehensive control.

[0050] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the application, which should be covered in 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 controlling the stable operation of an aircraft engine at idle speed, characterized in that, include: The following parameters are obtained: the change in fuel demand during steady-state operation in the backup idle state, the attenuation of backup idle control, the attenuation of backup acceleration fuel supply control, the deviation of main pump acceleration fuel supply under different fuel temperatures, the critical value of acceleration fuel supply affecting steady-state speed, the influence of intake manifold on acceleration fuel supply, and the dispersion of idle fuel demand. The deviation of engine acceleration fuel supply compared to steady-state fuel supply is then calculated. The deviation between accelerated fuel injection and steady-state fuel injection is converted to acceleration performance requirements, and the relationship curve between half-range acceleration time and atmospheric temperature is further obtained. The upper and lower limits of the half-range acceleration time are determined based on the relationship curve between the half-range acceleration time and the atmospheric temperature. The factory requirements are determined based on the upper and lower limits of the acceleration time. The backup idle speed is checked and the backup acceleration time requirement is set as the field requirement. The backup idle speed is controlled to ensure stable operation based on the factory requirements and the field requirements. By recording the idle oil volume WfR of the engine during long-term testing and the engine when it is put out of service and returned to the factory, the change in oil volume required for steady-state operation of the backup idle engine is obtained through data statistical evaluation. By statistical analysis of main pump long-term test data or by comparing the performance of main pump accessory testers with factory data during engine long-term test or return to the factory at the end of service life, the amount of backup slow-speed control attenuation can be obtained. By comparing the main pump's long-term test data or the main pump accessory tester's performance data with the factory data during the engine's long-term test or when the engine is returned to the factory at the end of its service life, the main pump's acceleration fuel supply control attenuation value is statistically analyzed to obtain the backup acceleration fuel supply control attenuation value. Tests were conducted on the main pump tester in conjunction with different fuel temperatures of the main pump to obtain the accelerated fuel supply deviation of the main pump under different fuel temperatures. The main pump tester was tested and verified. By gradually reducing the main pump's accelerated oil supply and performing performance evaluation, the critical value when accelerated oil supply affects steady-state speed control was obtained. By comparing the difference between (acceleration fuel supply - steady-state fuel supply) / steady-state fuel supply at the factory and (acceleration fuel supply - steady-state fuel supply) / steady-state fuel supply after installation, the influence of the intake manifold on acceleration fuel supply can be obtained. The fuel demand dispersion at idle speed is obtained by evaluating the dispersion of fuel demand at idle speed for different engines in steady state.

2. The method for controlling the stable operation of an aero-engine at idle speed as described in claim 1, characterized in that: After obtaining the deviation between the engine acceleration fuel supply and the steady-state fuel supply, the engine factory acceleration test data was corrected to standard atmospheric conditions and statistically analyzed to obtain the correspondence between the half-range acceleration time and the relative increase in acceleration fuel. After data fitting using the least squares method, the relationship curve between the half-range acceleration time and the atmospheric temperature was obtained.

3. The method for controlling the stable operation of an aircraft engine at idle speed as described in claim 1, characterized in that: After obtaining the deviation between the engine's accelerated fuel supply and steady-state fuel supply, acceleration performance was verified by conducting different acceleration fuel supply coefficients at a set atmospheric temperature to obtain the relative increase in acceleration fuel. For different relative increases in acceleration fuel, the upper limit of acceleration under different acceleration fuel supply coefficients was determined by the reserved range under the engine installation conditions without abnormalities. The relationship curve between half-range acceleration time and atmospheric temperature was obtained by statistically analyzing the half-range acceleration time at different atmospheric temperatures.

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