Aero-engine performance calculation method based on test data

Abstract

The invention provides an aero-engine performance calculation method based on test data, and relates to the technical field of aero-engine detection, and the method comprises the following steps: S1, installing an engine on a test bed; s2, recording parameters such as engine power, gas turbine front temperature, gas turbine rear temperature, fuel oil flow, oil consumption rate and the like at different rotating speed points; s3, calculating and analyzing the relationship between the rotating speed and the parameters such as the power, the gas turbine front temperature, the gas turbine rear temperature, the fuel oil flow and the oil consumption rate; s4, the performance of the engine in the specified state is calculated according to the relation between the different parameters and the rotating speed obtained through analysis, and compared with a traditional quadratic or cubic curve fitting method which does not consider the defects of engine performance degradation and manufacturing dispersity, the method has the advantages that the performance of the engine in the specified state is obtained by establishing a matrix equation and combining performance difference comparison under the order n = i and the order n = i + 1; the optimal fitting order is screened, for example, the power calculation error can be reduced, and meanwhile environment fluctuation interference is eliminated by matching atmosphere temperature, pressure and humidity real-time monitoring and parameter correction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine detection, and particularly relates to an aero-engine performance calculation method based on test data. BACKGROUND

[0002] Aero-engine performance calculation is a core link of bench test acceptance, and its result directly determines whether the engine meets the factory standard and airworthiness requirements. Currently, a quadratic or cubic polynomial curve fitting method is generally used to process bench test data in the industry, a function relationship of rotational speed and performance parameters such as power and gas turbine temperature is established, and performance calculation under specified states such as take-off and intermediate emergency state is realized. This method is widely used because it is simple to operate and can be realized by relying on conventional fitting tools.

[0003] However, the traditional curve fitting method has significant technical defects in actual application, and it is difficult to meet the needs of high-precision testing of aero-engines. First, it does not consider the influence of engine performance degradation and manufacturing dispersion. As a complex high-dimensional nonlinear system, the assembly parameter dispersion of the engine parts is large, and in the testing and use process, the core components such as the compressor and turbine will inevitably have performance degradation, and the calculation error caused by the part degradation after 300 hours of endurance test can be as high as 4.33%. The quadratic or cubic fixed order fitting is only based on instantaneous test data to construct a static relationship, which cannot adapt to the individual differences of different engines in manufacturing, and cannot reflect the dynamic changes of performance parameters caused by part degradation, resulting in deviation of the fitted curve from the actual working condition. SUMMARY

[0004] The purpose of the present application is to solve the problems in the prior art and provide an aero-engine performance calculation method based on test data.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: an aero-engine performance calculation method based on test data, characterized in that it comprises the following steps: S1, installing the engine to the ground test bench, connecting mechanical and electrical interfaces, and carrying out performance recording work according to the file requirements; S2, recording engine performance parameters at different rotational speed points, and before recording, the engine internal airflow and components should be in thermal equilibrium state for not less than 3 minutes, and the engine rotational speed should be gradually increased by a fixed step length first, and then gradually decreased by a same step length; S3, establishing a matrix equation according to the recorded performance points , and converting it into ; S4, bringing into and Solve the equation to determine the matrix ; S5, calculate the engine performance of the specified state according to the determined matrix, and compare and the performance difference, if the difference meets the specified requirements, the performance of the specified state point calculated when n=i is the result, and the engine performance under the specified conditions is obtained through the Mach number similarity criterion and compared with the acceptance standard.

[0006] Preferably, the performance parameters recorded in step S2 include engine power, gas turbine pre-temperature, gas turbine post-temperature, fuel flow, and fuel consumption rate.

[0007] Preferably, the step size when the speed is rising and the step size when the speed is falling in step S2 can be set to be inconsistent.

[0008] Preferably, the elements in the matrix are the power of the speed of the i-th recorded point, the elements in the matrix are the coefficients of the power term corresponding to the speed of each row in the matrix , and the elements in the matrix are the data of the i-th parameter at the j-th point.

[0009] Preferably, the specified conditions in step S5 are: sea level static, international standard atmosphere; the engine is equipped with a bench intake duct and an exhaust section; no helicopter system bleed air, anti-icing bleed air, and motor power extraction; the output shaft speed is kept constant.

[0010] Preferably, during the recording of performance parameters, an environmental parameter real-time monitoring module is added to collect atmospheric temperature, atmospheric pressure, and air humidity data in real time, and to perform environmental correction on the recorded performance parameters.

[0011] Preferably, when adjusting the speed, a multi-section step size setting is used to divide the speed range into a low speed section, a medium speed section, and a high speed section, and appropriate ascending and descending step sizes are set for each speed section.

[0012] Preferably, after obtaining the performance of the specified state point, a performance trend analysis step is added to construct an engine performance decay curve through continuous multiple test data to predict the performance trend in the subsequent use of the engine.

[0013] Preferably, it further includes a test data storage and tracing module, which encrypts and stores the speed data, performance parameter data, matrix solving process data, and final performance results of each test, and establishes a unique data index to facilitate subsequent data retrieval and problem tracing.

[0014] ​​The preferred, suitable for turbo shaft engine, turbojet engine and turbofan engine, for different types of engines, can adjust the matrix The value range of the middle speed power term and the recording type of the performance parameter.

[0015] Compared with the prior art, the advantages and positive effects of the present application are that, 1、In the present application, compared with the traditional quadratic or cubic curve fitting method which does not consider the defects of engine performance attenuation and manufacturing dispersion, the present method establishes a matrix equation and combines the performance difference comparison of n=i and n=i+1 order, selects the optimal fitting order, such as the power calculation error can be controlled within 2%, the gas turbine outlet temperature error can be controlled within 5℃, and at the same time, the real-time monitoring of atmospheric temperature and pressure and humidity and parameter correction are further used to eliminate the environmental fluctuation interference, so that the deviation between the performance calculation results of the specified state takeoff, intermediate emergency and actual values is greatly reduced, the judgment of whether the engine meets the acceptance standard is more accurate, and the risk of qualified engines being misjudged or unqualified engines flowing into the field due to calculation error is avoided.

[0016] 2、In the present application, by standardizing the bench installation process such as ensuring the coaxiality of the dynamometer and the output shaft, detecting the continuity of the sensor signal line, avoiding the influence of mechanical connection deviation and abnormal electrical signal on the test, using the control logic of gradually increasing the speed first and then gradually decreasing the speed, and setting a stable time of not less than 3 minutes at each speed point to take the speed fluctuation ±1r / min and the exhaust temperature fluctuation ±2℃ as the stability standard, the hysteresis effect of engine speed change and the disturbance of component thermal imbalance on parameters are effectively eliminated, at the same time, the adaptive step length is set for different speed sections low, medium and high, which is in line with the dynamic response characteristics of the engine, so that the performance parameters of each test point can truly reflect the stable working condition of the engine, and the data fluctuation caused by improper speed control is avoided, providing high-quality original data support for subsequent calculation.

[0017] 3、In the present application, by installing environmental sensors upstream of the bench inlet to collect real-time atmospheric temperature, pressure and humidity, and according to the preset formula such as power correction formula corrected power=measured power×standard atmospheric pressure / measured atmospheric pressure^0.7, the performance parameters are dynamically corrected, which solves the problem that the performance data is not comparable in traditional test due to environmental differences such as temperature and pressure changes in different regions and different time periods, and combines the Mach number similarity criterion to convert the bench data into performance values under the standard conditions of sea level stillness and international standard atmosphere, so that the performance results of different test environments and different batches of engines have a unified comparison benchmark, which is convenient for cross-scene acceptance judgment.

[0018] 4. In this invention, complete test data, including raw engine speed data, sensor calibration records, intermediate matrix solving processes, and final performance results, is stored in an encrypted database. A unique index is created for each test task, linking the test date, engine number, and test personnel, ensuring traceability throughout the entire testing process. When performance disputes or malfunctions occur subsequently, technicians can quickly retrieve historical data through the index, reconstruct the test calculation process, and accurately pinpoint the problem area, such as sensor calibration deviations or improper matrix order selection. This not only meets the aviation industry's compliance requirements for test data traceability but also significantly improves troubleshooting efficiency.

[0019] 5. In this invention, the method flexibly adjusts the types of performance parameters to be selected and the matrix fitting parameters. For example, for turbojet engines, thrust parameters are added and the range of the speed power term in the matrix is ​​adjusted to 3-5. For turbofan engines, bypass ratio-related parameters are added. This breaks the limitation of traditional methods that are only applicable to a single type of engine. It can be adapted to the performance testing needs of various aero-engines such as turboshaft, turbojet, and turbofan engines. There is no need to develop independent test schemes for different types of engines, which reduces the cost of technology research and development. At the same time, it expands the application scenarios of the method and facilitates its large-scale promotion in the field of aero-engine testing.

[0020] 6. In this invention, the optimal fitting order is determined by comparing the performance difference between orders n=i and n=i+1. When the difference meets the allowable error, such as a power difference ≤2%, there is no need to further increase the order. This avoids the problem of insufficient fitting accuracy at low orders and prevents redundant costs such as increased computational complexity and extended time consumption caused by high-order fitting. It achieves the optimal balance between computational accuracy and efficiency, and is especially suitable for batch engine factory testing scenarios, which can improve testing while ensuring accuracy. Detailed Implementation

[0021] This invention discloses a method for calculating the performance of an aero-engine based on test data, comprising the following steps: S1. Install the engine onto the ground test bench, connect the mechanical and electrical interfaces, and proceed according to the document requirements. Performance-based admissions work; S2. Record engine performance parameters at different speed points. Before recording, the engine must be stable for no less than 3 minutes in each working state to ensure that the internal airflow and components of the engine are in thermal equilibrium. When recording, the engine speed should first increase gradually in a fixed step size, and then decrease gradually in a corresponding step size. S3. Establish a matrix equation based on the performance points of the admitted students. and transform it into ; S4, will Substitute them separately and In the process, solving the equations determines the matrix. ; S5, calculating the engine performance of the specified state according to the determined matrix, and comparing and the performance difference at the time, if the difference meets the specified requirements, the performance of the specified state point calculated when n=i is the result, and the engine performance under the specified condition is obtained through the Mach number similarity criterion and compared with the acceptance standard.

[0022] Further, the performance parameters recorded in step S2 include engine power, gas turbine front temperature, gas turbine rear temperature, fuel flow, and fuel consumption rate.

[0023] Further, the step size when the speed is rising and the step size when the speed is falling in step S2 can be set to be inconsistent.

[0024] Further, the elements in the matrix are the th power of the speed of the i th recorded point, the elements in the matrix are the coefficients of the power term corresponding to the speed of each row in the matrix , and the elements in the matrix are the data of the i th parameter at the j th point.

[0025] Further, the specified condition in step S5 is specifically: sea level static, international standard atmosphere; the engine is equipped with a bench intake duct and an exhaust section; no helicopter system bleed air, anti-icing bleed air, and motor power extraction; the output shaft speed is kept constant.

[0026] Further, during the recording of the performance parameters, an environmental parameter real-time monitoring module is added to collect atmospheric temperature, atmospheric pressure, and air humidity data in real time, and to perform environmental correction on the recorded performance parameters.

[0027] Further, when adjusting the speed, a multi-section step size setting is used, dividing the speed range into low speed section, medium speed section, and high speed section, and setting appropriate ascending and descending step sizes for each speed section.

[0028] Further, after obtaining the performance of the specified state point, a performance trend analysis step is added to construct an engine performance decay curve through continuous multiple test data to predict the performance trend in the subsequent use of the engine.

[0029] Further, it also includes a test data storage and traceability module, which encrypts and stores the speed data, performance parameter data, matrix solving process data, and final performance results of each test, and establishes a unique data index, facilitating subsequent data retrieval and problem tracing.

[0030] ​​Further, suitable for turbo shaft engine, turbojet engine and turbofan engine, for different types of engines, the matrix can be adjusted The value range of the speed power term and the type of performance parameters are recorded.

[0031] Specifically, the method for calculating the performance of the aero-engine based on test data of the present application, the aero-engine is hoisted to the designated installation position of the ground test bench, the mechanical interface connection work is completed, among which the coaxiality of the dynamometer and the engine output shaft needs to be ensured to meet the requirements of the general specification for aero-engine test, and the electrical interface connection is completed, including connecting the signal lines of the speed sensor, the temperature sensor before the gas turbine, the temperature sensor after the gas turbine, and the fuel flow sensor with the corresponding ports of the data acquisition system, and performing line break detection to ensure normal signal transmission, then starting the engine according to the requirements of the relevant files for aero-engine performance test to prepare for performance recording work. During the performance recording process, first, the engine speed is controlled according to the set speed sequence, the speed change needs to follow the order of gradually rising first and then gradually falling, at each preset speed point, such as Ng1 is 1000r / min, Ng2 is 1500r / min, and Ngm is 8000r / min, the engine needs to be kept stable running, and the stable time is not less than 3 minutes, to judge whether the engine reaches the stable state, the standard is that the speed fluctuation amplitude in 30 seconds is not more than ±1r / min, and the exhaust temperature fluctuation amplitude is not more than ±2℃, at this time, the airflow and components in the engine are in thermal equilibrium state, the parameters representing the state of the engine no longer change with time, then the performance parameters of the speed point are recorded through the sensors and the data acquisition system, including the engine power, the temperature before the gas turbine, the temperature after the gas turbine, the fuel flow, and the fuel consumption rate calculated according to the fuel flow and the power, during the speed rising process, the fixed step can be set as 500r / min, during the speed falling process, the step can be adjusted according to the response characteristics of the engine at different speed intervals, such as setting as 600r / min, which does not need to be consistent with the rising step. According to the l performance parameter data of m speed points obtained by recording, a matrix equation is established Wherein the matrix is the n-i+1 power of the speed of the first I recording point, is the coefficient of each row of the matrix , is the data of the jth point of the i th recorded parameter (power, temperature, air flow)

[0032] Then, the established matrix equation is transformed by simultaneously left multiplying the transpose matrix of the matrix A on both sides of the equation to obtain the transformed equation . Substitute n = 2, 3, and so on into the matrix and the matrix Solve the transformation equation corresponding to each n value using linear algebra solving tools to obtain the matrix The performance parameters of the engine in the specified state, such as the take-off state, the intermediate emergency state, are calculated according to the matrix B obtained for different n values, including power, fuel consumption rate, gas turbine outlet temperature, and the difference of each performance parameter in the same specified state when n = i and n = i + 1 is calculated. The difference is compared with the preset allowable error range, such as the power difference not exceeding 2% and the temperature difference not exceeding 5°C. If the difference meets the allowable error requirement, the performance of the specified state point calculated when n = i is selected as the final calculation result. Then, according to the Mach number similarity criterion, the final calculation result is converted into the performance data of the engine under the specified conditions, which are specifically sea level static environment, international standard atmospheric temperature 15°C, atmospheric pressure 101.325 kPa. The engine installation bench is required to have a special intake and exhaust section, and the flow field characteristics of the intake and exhaust section meet the test standards. The helicopter system bleed air valve and anti-icing bleed air valve are closed to ensure no system bleed air. At the same time, the motor power extraction circuit is cut off to ensure no motor power consumption. The engine output shaft speed is kept constant by the dynamometer closed-loop control. During the process of recording the performance parameters, the environmental parameters are configured, and the related sensors and data processing units are monitored in real time. The atmospheric temperature sensor, atmospheric pressure sensor, and air humidity sensor are installed 1 meter upstream of the bench intake and are protected from direct sunlight and air flow disturbance. The data acquisition system collects environmental parameter data at a frequency of 1 per second and corrects the recorded performance parameters according to the preset environmental correction formula, such as correcting the power parameter according to the atmospheric pressure deviation. The corrected power = measured power × standard atmospheric pressure / measured atmospheric pressure) ^ 0.7 to eliminate the influence of environmental factors on the test results. When controlling the engine speed, a multi-section step setting method is used to divide the entire speed range into low speed section (1000-3000 r / min), medium speed section (3000-6000 r / min), and high speed section (6000-8000 r / min). The step size is set to 300 r / min in the low speed section, 500 r / min in the medium speed section, and 400 r / min in the high speed section. By adapting the dynamic response characteristics of the engine at different speed sections, it is ensured that each speed point can reach a stable thermal equilibrium state. After obtaining the performance data of the specified state points of the engine, a performance trend analysis link is added. Three performance tests are carried out on the same engine according to the same test process, with an interval of 24 hours between each test. The same specified state point performance data obtained from the three tests is arranged in chronological order, and a linear fitting method is used to construct an engine performance attenuation curve. Through the curve, the performance change trend of the engine in the subsequent use process is predicted, such as predicting the power attenuation of the engine after 100 hours of cumulative operation. This provides a basis for subsequent maintenance planning.The configuration test data storage and traceability related hardware and software system uses an encrypted database to store each test data, including the rotational speed data of each rotational speed point, the performance parameter original data, the intermediate data in the matrix solving process, the final performance calculation results, and the calibration records before each sensor test. A unique data index is established for each test task. The index information includes the test date, the engine serial number, and the test personnel number. If subsequent historical data needs to be retrieved or test problems need to be traced, the corresponding test record can be quickly located through the index. This method can be applied to different types of engines, such as turboshaft engines, turbojet engines, and turbofan engines. When testing different types of engines, related parameter settings need to be adjusted. For turbojet engines, thrust parameter recording needs to be added in the performance parameter recording link and the matrix. The value range of the rotational speed power term is adjusted to 3 to 5. For turbofan engines, related parameters such as bypass ratio, such as bypass airflow temperature and bypass airflow pressure, need to be recorded to adapt to the performance characteristics of different types of aeroengines.

[0033] The working principle of the aero-engine performance calculation method based on test data of the application is as follows: first, through the standardized bench installation process, the mechanical connection precision and electrical signal reliability during engine testing are ensured to provide a stable foundation for subsequent testing. In the performance recording stage, the method adopts the mode of first increasing and then decreasing the speed and sets a long enough stable time to eliminate the hysteresis effect in the engine speed change process and the influence of component thermal imbalance on parameter measurement, ensuring that the recorded performance parameters can truly reflect the stable state of the engine at the corresponding speed. By establishing a matrix equation and using transpose matrix transformation to solve, the method realizes the fitting of the relationship between performance parameters and speed based on the least square method. Compared with traditional quadratic or cubic curve fitting, this method can adapt to the performance characteristics of different engines by adjusting the fitting order (n value) while avoiding the error caused by the traditional method not considering engine performance decay and manufacturing dispersion. By comparing the performance difference between n=i and n=i+1, the optimal fitting order can be determined. When the difference meets the allowable error, it means that the fitting order at this time can ensure the calculation accuracy. Further increasing the order does not significantly improve the accuracy, thus balancing the calculation efficiency and accuracy. The application of the Mach number similarity criterion is to convert the performance data under the bench test environment into data under standard conditions (sea level, still, international standard atmosphere, etc.) to ensure the comparability of performance results under different test environments for accurate comparison with acceptance standards to determine whether the engine is qualified. Real-time monitoring and correction of environmental parameters are to eliminate the interference of test environment fluctuations (such as atmospheric pressure and temperature changes) on performance parameters. Multi-section step setting is to optimize the speed control logic according to the dynamic response characteristics of different engine speed sections, both of which serve to improve test accuracy. Performance trend analysis can achieve pre-judgment of engine performance by constructing a decay curve from continuous test data, providing a reference for subsequent use and maintenance. The test data storage and traceability system ensures the traceability of the test process, facilitating subsequent problem troubleshooting. Adjusting the types of parameters recorded and the matrix fitting order for different types of engines is to adapt to the performance characteristics of various engines to ensure the universality of the method. Finally, through the synergistic effect of the above steps, the precise calculation of the specified state performance of the aero-engine is realized, and the entire test calculation process can be reproduced by the skilled person in the art according to the principle.

[0034] The above merely describes preferred embodiments of the present application, but is not intended to limit the present application in other forms. Any person skilled in the art can make changes or modifications to the above disclosed technical contents to apply to other fields with equivalent embodiments of equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution content of the present application and in accordance with the technical essence of the present application still belongs to the protection scope of the technical solution of the present application. In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly. For example, it can be a fixed connection, or it can be a detachable connection, or it can be an integral connection; it can be a mechanical connection, or it can be an electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

Claims

1. A method for calculating the performance of an aero-engine based on test data, characterized in that, Includes the following steps: S1. Install the engine onto the ground test bench, connect the mechanical and electrical interfaces, and carry out performance testing according to the document requirements; S2. Record engine performance parameters at different speed points. Before recording, the engine must be stable for no less than 3 minutes in each working state to ensure that the internal airflow and components of the engine are in thermal equilibrium. When recording, the engine speed should first increase gradually in a fixed step size, and then decrease gradually in a corresponding step size. S3. Establish a matrix equation based on the performance points of the admitted students. and transform it into ; S4, will Substitute respectively and In the process, solving the equations determines the matrix. ; S5. Calculate the engine performance under specified conditions based on the determined matrix, and compare it with... and The performance difference at n=i is calculated. If the difference meets the specified requirements, the performance at the specified state point calculated at n=i is the result. Then, the engine performance under the specified conditions is obtained through the Mach number similarity criterion and compared with the acceptance standard.

2. The method for calculating the performance of aero-engines based on test data according to claim 1, characterized in that, The performance parameters recorded in step S2 include engine power, gas turbine inlet temperature, gas turbine outlet temperature, fuel flow rate, and fuel consumption rate.

3. The method for calculating aero-engine performance based on test data according to claim 1, characterized in that, In step S2, the step size when the speed increases and the step size when the speed decreases can be set to be different.

4. The method for calculating aero-engine performance based on test data according to claim 1, characterized in that, matrix The element in the middle is the rotation speed of the i-th admission point. Power, matrix The elements are matrices The coefficient of the power term corresponding to each row of rotational speeds in the matrix. The Chinese element is the first to be admitted The parameter in the first... Data from each point.

5. The method for calculating the performance of an aero-engine based on test data according to claim 1, characterized in that, The specific conditions specified in step S5 are: the sea level is still and the atmosphere is in international standard; the engine is equipped with a test bench air intake and exhaust section; there is no helicopter system bleed air, anti-icing bleed air, or motor power extraction; and the output shaft speed remains constant.

6. The method for calculating the performance of an aero-engine based on test data according to claim 1, characterized in that, During the performance parameter selection process, a real-time environmental parameter monitoring module was added to collect atmospheric temperature, atmospheric pressure, and air humidity data in real time, and to perform environmental corrections on the performance parameters.

7. The method for calculating the performance of an aero-engine based on test data according to claim 1, characterized in that, When adjusting the speed, a multi-segment step size setting is adopted, dividing the speed range into low speed segment, medium speed segment and high speed segment, and setting an appropriate lifting step size for each speed segment.

8. The method for calculating the performance of an aero-engine based on test data according to claim 1, characterized in that, After obtaining the performance at the specified state point, a performance trend analysis step is added. By constructing an engine performance degradation curve through multiple consecutive test data, the performance change trend of the engine during subsequent use can be predicted.

9. The method for calculating the performance of an aero-engine based on test data according to claim 1, characterized in that, It also includes a test data storage and traceability module, which encrypts and stores the rotation speed data, performance parameter data, matrix solution process data and final performance results of each test, and establishes a unique data index to facilitate subsequent data retrieval and problem traceability.

10. The method for calculating the performance of an aero-engine based on test data according to claim 1, characterized in that, Suitable for turboshaft engines, turbojet engines, and turbofan engines; the matrix can be adjusted for different engine types. The range of values ​​for the power term of the intermediate speed and the types of performance parameters to be selected.