A method for correcting characteristics of aircraft engine compression system

Abstract

The present invention provides a method for correcting characteristics of an aircraft engine compression system. The method can correct the characteristics of a compression component in real time according to actual measurement parameters during a test or when the engine is working, and can be used for real-time verification and diagnosis of the working conditions of the compression component and the engine. The method has the advantages of simple program implementation and good robustness, effectively improving efficiency and ensuring smooth progress of the test.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engines, and in particular relates to a method for correcting characteristics of a compression system of an aero-engine. Background Art

[0002] The impeller components in aircraft engines mainly include compression components and turbine components, including low-pressure compressor, high-pressure compressor, high-pressure turbine, low-pressure turbine, etc. The accuracy of their characteristics directly affects the prediction accuracy of the engine performance model. However, due to the differences in geometric parameters such as rotor-static clearance and blade angle and test conditions in the whole machine environment and in component tests, and even in the same whole machine environment, component performance will change with the increase of usage time. Therefore, its characteristics in the whole machine environment and during component tests are not the same, and there may be large differences. To obtain higher prediction accuracy of whole machine performance, it is necessary to correct the characteristics according to the actual performance of the engine.

[0003] According to similarity theory, the characteristics of impeller-type components can be expressed as isospeed lines composed of flow and pressure ratio curves at different speeds. Their complexity is greatly increased compared to channel-type components in engines. In adaptive / variable cycle engines, there are many flow paths, complex flows, and most impeller-type components are adjustable in design. It is more difficult to obtain high-precision characteristics of impeller-type components in real environments.

[0004] At present, there are two main methods for correcting the characteristics of components of turbines: one is to use the mapping method to generate more accurate component characteristics through the large amount of engine test data that has been obtained, so as to establish a more accurate aircraft engine performance model; the other is to correct the component characteristics based on the engine test data on the basis of the existing aircraft engine performance model based on component characteristics, so as to improve the calculation accuracy of the aircraft engine performance model, mainly based on genetic algorithms, iterative correction of influence coefficient matrix, model identification and other correction methods. However, a common feature of the above methods is that the correction of aircraft engine performance model and test performance calculation cannot be completed at the same time, resulting in a large amount of manual work, large amount of computer calculation and low efficiency in the correction of aircraft engine performance model. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide an online and fast method to improve the prediction accuracy of aircraft engine performance model and provide a basis for online gas path diagnosis and health assessment of various components.

[0006] In order to achieve the above object, the present invention provides the following technical solution, providing a method for correcting characteristics of an aircraft engine compression system, wherein the compression system includes a plurality of compression components, and the method includes the following steps:

[0007] S1: The characteristics of the first compression component are composed of several equal speed lines, which are expressed as (W c The three-dimensional coordinate points represented by , π, η) represent the characteristic points on each constant speed line;

[0008] S2: Calculate the relative conversion speed of the test according to the measured parameters of the inlet and outlet of the first compression component , Test conversion flow W c,t 、Test pressure ratio π t , test efficiency η t ;

[0009] S3: gridding and discretizing the first compression component characteristics loaded in S1;

[0010] S4: Use the three-cycle bisection method to numerically solve the virtual constant speed line;

[0011] S5: Backward interpolation to solve the measured W c,t or π t The β value β0 in the virtual constant speed line;

[0012] S6: The relative conversion speed of the test calculated based on S2 , interpolate the component characteristics loaded in S1 to obtain the test relative conversion speed The corresponding test speed constant line;

[0013] S7: interpolate β0 solved in S5 from the test constant speed curve obtained in S6 to obtain Wc0, π0, η0;

[0014] S8: Test conversion flow W calculated based on S2 ct 、Test pressure ratio π t , test efficiency η t Solve the Wc0, π0, and η0 calculated by S7 to obtain the flow coupling coefficient C W , pressure ratio coupling coefficient C π and efficiency coupling coefficient C η ;

[0015] S9: Flow coupling coefficient C obtained from S8 W , pressure ratio coupling coefficient C π and efficiency coupling coefficient C η Correcting the first compression component characteristic loaded by S1 to obtain a corrected first compression component characteristic;

[0016] S10: The remaining compression components are corrected according to S1-S9, and finally the correction characteristics of each compression component in the compression system are obtained.

[0017] The method for correcting the characteristics of the aircraft engine compression system provided by the present invention also has the following characteristics: when the compression component is a core engine drive fan, the inlet and outlet total temperature / total pressure distribution is measured according to its component level test, and the outlet total temperature and total pressure of the core engine drive fan in the aircraft engine or core engine are corrected according to the distribution law of the measuring points;

[0018] When the compression component is not at the front end of the engine compression system, its inlet conversion flow W ct The result is obtained by iterative calculation based on the principle that the throat converted flow rate remains unchanged under the critical state of the high-pressure turbine guide vane and the actual fuel flow measurement data participating in the combustion.

[0019] The method for correcting the characteristics of the aircraft engine compression system provided by the present invention also has the following characteristics: S3 comprises the following steps:

[0020] S3.1: Define dimensionless β number, β is a real number;

[0021] S3.2: Divide each converted flow-pressure ratio isospeed line into n equal parts according to the arc length to generate n+1 equal parts, and number the equal parts on each converted flow-pressure ratio isospeed line in the same order, and number them as P1(Wc1,π1), P2(Wc2,π2), ..., P i (Wc i ,π i ), ..., P n+1 (Wc n+1 ,π n+1 ), where n≥20;

[0022] S3.3: Obtain each equally divided point P on the converted flow-pressure ratio equal speed line i (Wc i ,π i ) then, according to Wc i The efficiency η at the equal points is obtained by converting the flow rate-efficiency isospeed line or interpolating the pressure ratio-efficiency isospeed line according to πi. i , and obtain the efficiency η i After that, each equally divided point P i Transformed into three-dimensional coordinates P i (Wc i ,π i ,η i );

[0023] S3.4: Connect the points with the same number on each equally divided converted flow-pressure ratio isospeed line to obtain n+1 auxiliary β lines. Each auxiliary β line has a corresponding β value, which is calculated based on the number of the equally divided points connected by the corresponding auxiliary β line. The β value β of the β line formed by connecting the points numbered i is i for:

[0024] β i =1+(i-1)*2 / n;

[0025] S3.5: The characteristics of the first compression component after discretization are:

[0026]

[0027]

[0028]

[0029] The method for correcting the characteristics of the aircraft engine compression system provided by the present invention also has the following characteristics: S3.3 includes: to ensure the interpolation accuracy and robustness, if along the conversion flow-pressure ratio equal speed line W ci The absolute value of the rate of change is greater than π i The absolute value of the rate of change of Wc i The efficiency η at the equal points is obtained by interpolating the converted flow-efficiency isospeed line. i On the contrary, according to π i The efficiency η at the equal points is obtained by interpolating the pressure ratio-efficiency constant speed line. i , where W ci The rate of change is π i The rate of change is

[0030] The method for correcting the characteristics of the aircraft engine compression system provided by the present invention also has the following characteristics: S4 comprises the following steps:

[0031] S4.1: given the two end point speed values ​​of the speed range, interpolating the flow rate-pressure ratio speed constant line of the loaded first compression component according to the average value of the two end point speed values ​​to obtain an initial virtual speed constant line;

[0032] S4.2: Determine π t Whether it is between the blocking point pressure ratio of the virtual constant speed line and the surging point pressure ratio of the virtual constant speed line, if so, proceed to S4.3; if not, return to S4.1;

[0033] S4.3: According to π t The virtual flow Wc on the interpolated virtual constant speed line v With test flow Wc t Compare and obtain the residual;

[0034] S4.4 performs the cyclic iteration of S4.1 and S4.3 until the residual is smaller than the target, and obtains the virtual constant speed line after iteration.

[0035] The method for correcting the characteristics of the compression system of an aircraft engine provided by the present invention also has the following characteristics: in S5, β in the virtual constant speed line obtained in S4 is expressed as β=f(π), and β0 is solved by interpolation: β0=f(π t ).

[0036] The method for correcting the characteristics of the aircraft engine compression system provided by the present invention also has the following characteristics: S7 comprises the following steps:

[0037] S7.1: Based on the discretized characteristics obtained in S3, the test relative conversion speed obtained in S6 is converted by common interpolation methods such as Lagrange interpolation. The corresponding test speed constant line is expressed as:

[0038]

[0039]

[0040]

[0041] S7.2: Substitute the β0 obtained in S6 into the test constant speed line expressed by the formula in S7.1 and solve by interpolation to obtain

[0042] Wc0=f(n c,t ,β0)

[0043] π0=f(n c,t ,β0)

[0044] η0=f(n c,t ,β0).

[0045] The method for correcting the characteristics of an aircraft engine compression system provided by the present invention also has the characteristic that after the compression components are replaced with aircraft engine turbine components, the method can also be used to correct the characteristics of aircraft engine turbine components.

[0046] Beneficial Effects

[0047] The method for correcting characteristics of an aircraft engine compression system provided by the present invention can provide compression component characteristic correction in real time according to actual measurement parameters during a test or engine operation, provide a basis for quickly correcting an aircraft engine performance model, and perform real-time verification and diagnosis of turbine components and engine operating conditions. It has the advantages of simple program implementation and good robustness, effectively improves efficiency, and ensures smooth progress of the test.

[0048] The basic steps and ideas of the method for correcting the characteristics of the aircraft engine compression system provided by the present invention can be used to correct the characteristics of other impeller components in the aircraft engine (such as the high-pressure turbine and the low-pressure turbine), thereby further improving the efficiency of correcting the aircraft engine performance model. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flow chart of a feature correction method provided by an embodiment of the present invention;

[0050] Figure 2 A flow chart of solving virtual constant speed lines by double-loop dichotomy in the feature correction method provided in an embodiment of the present invention;

[0051] Figure 3 Schematic diagram of the characteristics of the compression component in the embodiment of the present invention, wherein the upper figure is a converted flow-efficiency characteristic diagram, and the lower figure is a converted flow-pressure ratio characteristic diagram;

[0052] Figure 4 It is a characteristic schematic diagram of a turbine component in an embodiment of the present invention;

[0053] Figure 5 A schematic diagram of networked discrete compression characteristics in an embodiment of the present invention;

[0054] Figure 6 It is a schematic diagram of interpolation solution of actual characteristic lines in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The present invention is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation modes are not limitations of the present invention, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation modes are all within the scope of protection of the present invention.

[0056] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the invention.

[0057] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0058] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0059] Although the manufacturing process, working environment, and usage time will all affect the characteristics of engine turbine components, the basic change trend of their characteristics has the characteristics of being maintained, that is, the trend and shape of the characteristic line remain basically unchanged. This provides an important theoretical basis for correcting the characteristics of turbine components based on engine test data.

[0060] like Figure 1-4 As shown, this embodiment provides a method for correcting characteristics of an aircraft engine compression system, wherein the compression system includes a plurality of compression components, and the method includes the following steps:

[0061] S1: The characteristic of the first compression component is loaded. The characteristic of the first compression component is composed of a number of equal speed lines. The three-dimensional coordinate points represented by (Wc, π, η) represent the characteristic points on each equal speed line.

[0062] S2: Calculate the test relative conversion speed n based on the measured parameters of the inlet and outlet of the first compression component c,t , Test conversion flow W ct 、Test pressure ratio π t , test efficiency η t ;

[0063] S3: gridding and discretizing the first compression component characteristics loaded in S1;

[0064] S4: Three-cycle bisection method to solve virtual constant speed lines;

[0065] S5: Backward interpolation to solve the measured W ct or π t The β value β0 in the virtual constant speed line;

[0066] S6: The relative conversion speed of the test calculated based on S2 Interpolate the component characteristics loaded in S1 to obtain the test relative conversion speed The corresponding test speed constant line;

[0067] S7: interpolate β0 solved in S5 from the test constant speed curve obtained in S6 to obtain Wc0, π0, η0;

[0068] S8: Test conversion flow W calculated based on S2 ct、Test pressure ratio π t , test efficiency ηt and Wc0, π0, η0 calculated by S7 are solved to obtain the flow coupling coefficient C W , pressure ratio coupling coefficient C π and efficiency coupling coefficient C η ;

[0069] S9: Flow coupling coefficient C obtained from S8 W , pressure ratio coupling coefficient C π and efficiency coupling coefficient C η Correcting the first compression component characteristic loaded by S1 to obtain a corrected first compression component characteristic;

[0070] S10: The remaining compression components are corrected according to S1-S9, and finally the correction characteristics of each compression component in the compression system are obtained.

[0071] In some embodiments, when the compression component is a core engine drive fan, the inlet and outlet total temperature / total pressure distribution is measured according to its component-level test, and the outlet total temperature and total pressure of the core engine drive fan in the aircraft engine or core engine are corrected according to the distribution law of the measuring points; when the compression component is not at the front end of the engine compression system, its inlet converted flow rate W ct The result is obtained by iterative calculation based on the principle that the throat converted flow rate remains unchanged under the critical state of the high-pressure turbine guide vane and the actual fuel flow measurement data participating in the combustion.

[0072] In some embodiments, S3 includes the following steps:

[0073] S3.1: Define dimensionless β number, β is a real number;

[0074] S3.2: Divide each converted flow-pressure ratio isospeed line into n equal parts according to the arc length to generate n+1 equal parts, and number the equal parts on each converted flow-pressure ratio isospeed line in the same order, and number them as P1(Wc1,π1), P2(Wc2,π2), ..., P i (Wc i ,π i ), ..., P n+1 (Wc n+1 ,π n+1 ), where n≥20;

[0075] S3.3: Obtain each equally divided point P on the converted flow-pressure ratio equal speed line i (Wc i ,π i ) then, according to Wc i The efficiency η at the equal points is obtained by converting the flow rate-efficiency isospeed line or interpolating the pressure ratio-efficiency isospeed line according to πi.i , and obtain the efficiency η i After that, each equally divided point P i Transformed into three-dimensional coordinates P i (Wc i ,π i ,η i );

[0076] S3.4: Connect the points with the same number on each equally divided converted flow-pressure ratio isospeed line to obtain n+1 auxiliary β lines. Each auxiliary β line has a corresponding β value, which is calculated based on the number of the equally divided points connected by the corresponding auxiliary β line. The β value β of the β line formed by connecting the points numbered i is i for:

[0077] β i =1+(i-1)*2 / n;

[0078] S3.5: The characteristics of the first compression component after discretization are:

[0079]

[0080]

[0081]

[0082] In some embodiments, S3.3 includes: To ensure interpolation accuracy and robustness, if along the converted flow-pressure ratio equal speed line W ci The absolute value of the rate of change is higher than π i The absolute value of the rate of change of Wc i The efficiency η at the equal points is obtained by interpolating the converted flow-efficiency isospeed line. i On the contrary, according to π i The efficiency η at the equal points is obtained by interpolating the pressure ratio-efficiency constant speed line. i , where the converted flow-efficiency isospeed line has the converted flow as the x-axis and the efficiency as the y-axis; the pressure ratio-efficiency isospeed line has the pressure ratio as the x-axis and the efficiency as the y-axis, W ci The rate of change is π i The rate of change is

[0083] In some embodiments, S4 comprises the following steps:

[0084] S4.1: given the two end point speed values ​​of the speed range, interpolating the flow rate-pressure ratio speed line of the loaded first compression component according to the average value of the two end point speed values ​​to obtain an initial virtual speed line;

[0085] S4.2: Determine πt Whether it is between the blocking point pressure ratio of the virtual constant speed line and the surge point pressure ratio of the virtual constant speed line, if yes, proceed to S4.3; if not, return to S4.1; wherein, the blocking point pressure ratio is the pressure ratio corresponding to the point with the lowest pressure ratio or the point with the largest flow rate in the characteristic diagram; the surge point pressure ratio is the pressure ratio corresponding to the point with the highest pressure ratio or the point with the smallest flow rate in the characteristic diagram;

[0086] S4.3: According to π t The virtual flow Wc on the interpolated virtual constant speed line v With test flow Wc t Compare and obtain the residual;

[0087] S4.4 performs the cyclic iteration of S4.1 and S4.3 until the residual is smaller than the target, and obtains the virtual constant speed line after iteration.

[0088] In some embodiments, in S5, β in the virtual constant speed line obtained in S4 is expressed as β=f(π), and β0 is solved by interpolation: β0=f(π t ).

[0089] In some embodiments, S7 includes the following steps:

[0090] S7.1: Based on the discretized characteristics obtained in S3, the test relative conversion speed obtained in S6 is converted by common interpolation methods such as Lagrange quadratic interpolation. The corresponding test speed constant line is expressed as:

[0091]

[0092]

[0093]

[0094] S7.2: Substitute the β0 obtained in S6 into the test constant speed line expressed by the formula in S7.1 and solve by interpolation to obtain

[0095] Wc0=f(n c,t ,β0)

[0096] π0=f(n c,t ,β0)

[0097] η0=f(n c,t ,β0).

[0098] In some embodiments, after the compression component is replaced with an aircraft engine turbine component, the method can also be used to modify the characteristics of the aircraft engine turbine component.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A method for correcting characteristics of an aircraft engine compression system, wherein the compression system comprises a plurality of compression components, characterized in that: The method comprises the following steps: S1: The characteristics of the first compression component are composed of several equal speed lines, which are expressed as (W c The three-dimensional coordinate points represented by , π, η) represent the characteristic points on each constant speed line; S2: Calculate the relative conversion speed of the test according to the measured parameters of the inlet and outlet of the first compression component Test conversion flow W ct 、Test pressure ratio π t , test efficiency η t ; S3: gridding and discretizing the first compression component characteristics loaded in S1; S4: Use the three-cycle bisection method to numerically solve the virtual constant speed line; S5: Backward interpolation to solve the measured W ct or π t The β value β0 in the virtual constant speed line; S6: The relative conversion speed of the test calculated based on S2 Interpolate the component characteristics loaded in S1 to obtain the test relative conversion speed The corresponding test speed constant line; S7: Interpolate the β0 obtained in S5 from the test constant speed curve obtained in S6 to obtain Wc0, π0, η 0； S8: Calculate the test conversion flow W based on S2 ct 、Test pressure ratio π t , test efficiency η t Solve the Wc0, π0, and η0 calculated by S7 to obtain the flow coupling coefficient C W , pressure ratio coupling coefficient C π and efficiency coupling coefficient C η ; S9: Flow coupling coefficient C obtained from S8 W , pressure ratio coupling coefficient C π and efficiency coupling coefficient C η Correcting the first compression component characteristic loaded by S1 to obtain a corrected first compression component characteristic; S10: The remaining compression components are corrected according to S1-S9, and finally the correction characteristics of each compression component in the compression system are obtained. The S3 comprises the following steps: S3.1: Define dimensionless β number, β is a real number; S3.2: Divide each converted flow-pressure ratio isospeed line into n equal parts according to the arc length to generate n+1 equal parts, and number the equal parts on each converted flow-pressure ratio isospeed line in the same order, and number them as P1(Wc1,π1), P2(Wc2,π2), ..., P i (Wc i ,π i ), ..., P n+1 (Wc n+1 ,π n+1 ), where n≥20; S3.3: Obtain each equally divided point P on the converted flow-pressure ratio equal speed line i (Wc i ,π i ) then, according to Wc i The efficiency η at the equal points is obtained by converting the flow rate-efficiency isospeed line or interpolating the pressure ratio-efficiency isospeed line according to πi. i , and obtain the efficiency η i After that, each equally divided point P i Transformed into three-dimensional coordinates P i (Wc i ,π i ,η i ); S3.4: Connect the points with the same number on each equally divided converted flow-pressure ratio isospeed line to obtain n+1 auxiliary β lines. Each auxiliary β line has a corresponding β value, which is calculated based on the number of the equally divided points connected by the corresponding auxiliary β line. The β value β of the β line formed by connecting the points numbered i is i for: b i =1+(i-1)*2 / n; S3.5: The characteristics of the first compression component after discretization are:

2. The method for correcting the characteristics of an aircraft engine compression system according to claim 1, characterized in that: When the compression component is a core engine drive fan, the inlet and outlet total temperature / total pressure distribution is measured according to the component-level test, and the outlet total temperature and total pressure of the core engine drive fan in the aircraft engine or core engine are corrected according to the distribution law of the measuring points; When the compression component is not at the front end of the engine compression system, its inlet converted flow Wct is obtained by iterative calculation based on the principle that the throat converted flow is unchanged under the critical state of the high-pressure turbine guide vane and the actual fuel flow measurement data participating in the combustion.

3. The method for correcting the characteristics of an aircraft engine compression system according to claim 1, characterized in that: The S3.3 includes: To ensure the interpolation accuracy and robustness, if along the converted flow-pressure ratio equal speed line W ci The absolute value of the rate of change is greater than π i The absolute value of the rate of change of Wc i The efficiency η at the equal points is obtained by interpolating the converted flow-efficiency isospeed line. i On the contrary, according to π i The efficiency η at the equal points is obtained by interpolating the pressure ratio-efficiency constant speed line. i , where W ci The rate of change is π i The rate of change is 4. The method for correcting the characteristics of an aircraft engine compression system according to claim 1, characterized in that: The S4 comprises the following steps: S4.1: given the two end point speed values ​​of the speed range, interpolating the flow rate-pressure ratio speed constant line of the loaded first compression component according to the average value of the two end point speed values ​​to obtain an initial virtual speed constant line; S4.2: Determine π t Is it between the blocking point pressure ratio of the virtual constant speed line and the surging point pressure ratio of the virtual constant speed line? If so, proceed to S4.3; If not, return to S4.1; S4.3: According to π t The virtual flow Wc on the interpolated virtual constant speed line v With test flow Wc t Compare and obtain the residual; S4.4 performs the cyclic iteration of S4.1 and S4.3 until the residual is smaller than the target, and obtains the virtual constant speed line after iteration.

5. The method for correcting characteristics of an aircraft engine compression system according to claim 1, characterized in that: In S5, β in the virtual constant speed line obtained in S4 is expressed as β=f(π), and β0 is solved by interpolation: β0=f(π t ).

6. The method for correcting characteristics of an aircraft engine compression system according to claim 1, characterized in that: The S7 includes the following steps: S7.1: Based on the discretized characteristics obtained in S3, the test relative conversion speed obtained in S6 is converted by common interpolation methods such as Lagrange quadratic interpolation. The corresponding test speed constant line is expressed as: S7.2: Substitute the β0 obtained in S6 into the test constant speed line expressed by the formula in S7.1 and solve by interpolation to obtain Wc0=f(n c,t ,β0) π0=f(n c,t ,β0) η0=f(n c,t ,β0).

7. The method for correcting characteristics of an aircraft engine compression system according to claim 1, characterized in that: After the compression component is replaced by an aircraft engine turbine component, the method is also used to correct the characteristics of the aircraft engine turbine component.

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