CN111339686A - Turboshaft engine reverse modeling method based on test data - Google Patents
Turboshaft engine reverse modeling method based on test data Download PDFInfo
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Abstract
The invention discloses a turboshaft engine reverse modeling method based on test data, and belongs to the field of aero-engines. The implementation method of the invention comprises the following steps: carrying out state conversion on test data of a plurality of test points of the turboshaft engine to obtain a test point data set in a target test state; screening data in the test point data set to obtain a screened test point data set; according to the plurality of actually measured parameters, sequentially performing parameter trial and error on the plurality of trial and error iteration parameters to obtain a primary turboshaft engine model; adjusting the characteristics of the universal parts, and calibrating a preliminary turboshaft engine model by combining throttling test data; and performing Reynolds number and clearance correction on the calibrated turboshaft engine model to obtain a target turboshaft engine model. The invention directly utilizes the test data without depending on the test characteristics of the components, can complete the model construction in a short time and keeps high precision. The method has the advantages of simple operation and strong applicability.
Description
Technical Field
The invention relates to a turboshaft engine pneumatic thermal model construction method, in particular to a turboshaft engine reverse model construction method based on test data, which is suitable for engine model construction only with turboshaft engine complete machine test data and without engine part test characteristics, and carries out turboshaft engine pneumatic thermal performance prediction, and belongs to the field of aeroengines.
Background
The aircraft engine mathematical model is an important tool for evaluating and predicting the service performance of the aircraft engine in different flight states, and is widely applied in the development process of the aircraft engine.
The construction of aircraft engine mathematical models typically relies on a large number of component test features as supports. On the basis, the component characteristics are proportionally adjusted according to parameters such as flow rate, pressure ratio and the like. And then testing parameters in the characteristics of components such as a gas compressor, a turbine, a combustion chamber and the like according to the flow continuity equation, the energy conservation equation, the power balance equation, the rotating speed matching and other criteria under the condition of the whole machine, and iterating until the criteria are simultaneously achieved to obtain a model predicted value. And repeating the processes until the deviation between the obtained mathematical model predicted value and the test value meets certain precision. The construction of the engine mathematical model based on the test characteristics of the components is called forward modeling. The method can be established only by relying on the test characteristics of a large number of parts, and the established model has large error and low precision.
An aeroengine mathematical model independent of part test characteristics is constructed, the simulation precision of the model is improved, and the model is the leading edge of the performance analysis of the existing engine.
Disclosure of Invention
The invention discloses a turboshaft engine reverse modeling method based on test data, which aims to solve the technical problems that: under the condition that characteristics of a turboshaft engine body part are not available, high-altitude performance data obtained in an engine test are completely used as modeling resources, a turboshaft engine reverse modeling method which directly utilizes test data and does not need to depend on the characteristics of the part test is provided, an aviation turboshaft engine model is constructed, the precision and the efficiency of the model in test evaluation of the turboshaft engine are improved, and further the test high-altitude performance evaluation precision is improved. The method has the advantages of simple operation and strong applicability. The method has important significance in the aspects of engine test data validity, engine performance evaluation and the like, and solves the problems of relevant engineering of the turboshaft engine.
The purpose of the invention is realized by the following technical scheme:
the invention discloses a reverse modeling method of a turboshaft engine based on test data, which comprises the steps of carrying out state conversion on the test data of a plurality of test points of the turboshaft engine to obtain a test point data set in a target test state; screening data in the test point data set to obtain a screened test point data set; according to the plurality of actually measured parameters, sequentially performing parameter trial and error on the plurality of trial and error iteration parameters to obtain a primary turboshaft engine model; adjusting the characteristics of the universal parts, and calibrating a preliminary turboshaft engine model by combining throttling test data; and performing Reynolds number and clearance correction on the calibrated turboshaft engine model to obtain a target turboshaft engine model. The invention directly utilizes the test data without depending on the test characteristics of the components, can complete the model construction in a short time and keeps high precision. The method has the advantages of simple operation and strong applicability.
The invention discloses a turboshaft engine reverse modeling method based on test data, which comprises the following steps:
step 1: and analyzing and processing the test data of the turboshaft engine. Checking bad points in data by using continuity check of the same parameters of the turboshaft engine under different throttling states; and converting the air flow and the rotating speed of the gas turbine to the state of the international standard atmospheric sea level, and converting the other section parameters to the uniform test state.
And (4) carrying out preliminary confirmation on test data by using data assistance, and analyzing and pre-estimating design index parameters of each part. Checking dead pixels in data by using continuity check of the same parameters of the engine under different throttling states; and converting the air flow and the rotating speed of the gas turbine to the state of the international standard atmospheric sea level, and converting the other section parameters to the uniform test state.
The data assistance comprises a test point layout, an aircraft engine structure section, a design report and a specification.
Step 2: in order to ensure the precision of reversely constructing the turboshaft engine model, an engine test state point is selected. The engine test state point selection method comprises the following steps: selecting test point data by adopting Reynolds number index screening, ensuring that the test data simply reflects the pneumatic-thermal matching relation in the engine, and eliminating the influence of Reynolds number; the test data of the high state is selected through the engine state screening, so that the test point selected as the preliminary mathematical model of the heat is ensured to have a higher working state, the engine is under a higher load, the sensor is in a higher-precision measurement interval, and the relative error of each measured parameter is smaller. And selecting test points with more throttle states by adopting the throttle state screening, so that more available data can be ensured during the subsequent calibration of the reversely constructed turboshaft engine model, and the more data, the more beneficial the final precision of the subsequently reversely constructed turboshaft engine model.
Step 2.1: and selecting test point data by adopting Reynolds number index screening, ensuring that the test data simply reflects the pneumatic-thermal matching relation in the engine, and eliminating the influence of Reynolds number.
And (3) Reynolds number index screening is carried out on the test data of the turboshaft engine in the step (1), and the test point set 1 with the RNI index larger than a preset screening threshold is selected as a to-be-selected test point set, so that the test data can simply reflect the pneumatic thermal power matching relation in the engine, and the Reynolds number influence can be eliminated. The RNI index is calculated by formula (1).
Wherein: RNI Reynolds number index, Pt as total intake pressure at current test point, and PtrefIs referred to as total pressure, RrefIs a reference gas constant, R is a test point gas constant, TtrefIs the reference total temperature Tt is the intake total temperature mu of the current test pointrefFor reference aerodynamic viscosity, μ is the aerodynamic viscosity at the test point.
Step 2.2: the test data of the high state is selected through the engine state screening, the selected test point is ensured to have a higher working state, the engine is in a higher load, the sensor is in a higher-precision measurement interval, and the relative error of each measured parameter is smaller.
And (3) screening the engine state of the test data of the turboshaft engine in the step (2.1), selecting a test point set 2 with the relative conversion rotating speed of the gas turbine larger than a preset screening threshold value, ensuring that the selected test point as a preliminary mathematical model of heat power has a higher working state, the engine is in a higher load, the sensor is in a higher-precision measurement interval, and the measured parameters have smaller relative errors. The gas turbine relative reduced rotation speed is calculated by equation (2).
Wherein: n is a radical of1corGas turbine reduced speed, N1，ISA，SLS，1.0For the design rotational speed.
Step 2.3: and selecting test points with more throttle states by adopting throttle state screening, so that more available data can be ensured during subsequent calibration of the reversely constructed turboshaft engine model, and the more data, the more beneficial the final precision of the subsequently reversely constructed turboshaft engine mathematical model.
And (3) screening the engine throttling state of the test data of the turboshaft engine in the step (2.2), selecting a test point set 3 with more throttling states, wherein more available data are provided during subsequent calibration of the reversely constructed turboshaft engine model, and the more data are, the more beneficial the final precision of the subsequently reversely constructed turboshaft engine model is.
And step 3: and (3) establishing a preliminary turboshaft engine model by using the test data of the engine test state points selected in the step (2) through parameter iteration trial and error.
Sequentially carrying out parameter trial and error on a plurality of trial and error iteration parameters in the aerodynamic thermodynamic model by using the test data of the engine test state points selected in the step 2 to obtain an initial turboshaft engine model, which comprises the following steps:
according to the actually measured physical air flow, performing trial and error on the air flow converted by an inlet in the aerodynamic model;
according to the actually measured fuel flow, testing and collecting the outlet temperature of the combustion chamber in the aerodynamic thermodynamic model;
according to the actually measured outlet temperature of the gas compressor, the efficiency of the gas compressor in the pneumatic thermodynamic model is tried and found;
according to the actually measured shaft power, testing and collecting the efficiency of the power turbine in the pneumatic thermodynamic model;
and obtaining a primary turboshaft engine model after the sequential trial and completion.
And 4, step 4: and (3) calibrating the model by utilizing the preliminary turboshaft engine model and the throttling state test data established in the step (3) and adjusting the characteristics of the universal part to obtain the characteristics of the calibrated rear part and the turboshaft engine model, and constructing the turboshaft engine model based on the test data. The general component characteristic adjusting method comprises an efficiency adjusting method, a rotating speed adjusting method and a common working line adjusting method.
And (3) selecting the part characteristics according to the grade, the total pressure ratio and the flow based on the preliminary turboshaft engine model established in the step (3), and calibrating the throttling state to obtain the calibrated part characteristics. The general-purpose component characteristic adjustment method includes an efficiency adjustment method, a rotation speed adjustment method, and a variable adjustment method. The efficiency adjusting method comprises the steps of performing efficiency translation adjustment on the characteristics of the selected part according to the efficiency distribution of the throttling state actually measured in the test, and keeping a circulating reference point unchanged during adjustment; the rotating speed adjusting method is used for adjusting the rotating speed in the component characteristics according to a rotating speed translation method, and only the corresponding rotating speed value is changed without changing the position of a rotating speed line of the component during adjustment; adjusting a common working line of the components, carrying out variable geometric adjustment according to the relation between the pressure ratio and the air flow of the air compressor measured actually in a test, and carrying out up-and-down adjustment on the common working line at different rotating speeds. The method for adjusting the characteristics of the universal component is used for calibrating the throttling state to obtain the characteristics of the calibrated component, and the reverse construction model of the turboshaft engine based on the test data is constructed by utilizing the characteristics of the calibrated component.
And 5, correcting the turboshaft engine reverse construction model based on the test data constructed in the step 4 by using the part characteristics calibrated in the step 4 and combining a correction method of full-envelope error information, and further improving the model precision to obtain a target model. The method for correcting the full-envelope error information comprises a Reynolds number correction method and a gap correction method.
And (4) correcting the turboshaft engine reverse construction model based on the test data constructed in the step (4) by using the part characteristics calibrated in the step (4) and combining a correction method of full-envelope error information, and further improving the model precision. Before the precision of a turboshaft engine reverse construction model based on test data is further improved, model test deviation of overall parameters and pressure parameters is defined as relative error, and model test deviation of temperature is defined as absolute error. The method for correcting the full-envelope error information comprises a Reynolds number correction method and a gap correction method.
The Reynolds number correction method comprises the following steps: observing the distribution relation of the error of each point along with the engine inlet pressure, introducing Reynolds number correction if the error magnitude and the pressure distribution show obvious correlation and the condition that the oil consumption rate parameter is lower than a test value is shown under the condition of low inlet pressure, properly reducing the efficiency of a compression part when the engine inlet pressure is lower, and determining the reduction amplitude according to experience and the distribution improvement condition of the full envelope error.
The clearance correction method comprises the following steps: observing the distribution relation of the error of each point along with the temperature of an inlet of the engine, introducing clearance correction if the error shows obvious correlation along with the temperature, specifically adjusting the correction quantity of the clearance correction of the top end of the blade designed in the pneumatic thermodynamic cycle program, wherein the adjustment amplitude is determined according to experience and the distribution improvement condition of the full envelope error.
Further comprising the step 6: according to the target model in the step 5, the precision of the model in the test evaluation of the turboshaft engine is improved, the performance prediction precision of the turboshaft engine is improved, the effectiveness identification rate of test acquisition data is improved, the high altitude performance evaluation precision of the test is improved, and the problems of related engineering of the turboshaft engine are solved in engineering application.
Preferably, in the step 5, a model is reversely constructed on the basis of the test data of the turboshaft engine, the simulation error of the main performance parameter in the full envelope range of the turboshaft engine is increased to be within 1% from about 5%, the performance prediction level of the turboshaft engine can be greatly improved, the test data can also be used for judging the effectiveness of the test data, and the problem of relevant engineering in the application field of the turboshaft engine is solved.
Has the advantages that:
1. the invention discloses a reverse modeling method of a turboshaft engine based on test data, which comprises the steps of carrying out state conversion on the test data of a plurality of test points of the turboshaft engine to obtain a test point data set in a target test state; screening data in the test point data set to obtain a screened test point data set; according to the plurality of actually measured parameters, sequentially performing parameter trial and error on the plurality of trial and error iteration parameters to obtain a primary turboshaft engine model; adjusting the characteristics of the universal parts, and calibrating a preliminary turboshaft engine model by combining throttling test data; the invention provides a reverse modeling method which does not depend on part test characteristics and only utilizes test data, can avoid the dependence of the traditional turboshaft engine modeling method on accurate part test characteristics, and has more loose modeling conditions.
2. The invention discloses a turboshaft engine reverse modeling method based on test data, which utilizes the test data to participate in a modeling process, has less adjustment parameters, is simple to operate and high in efficiency, and achieves the model precision of a conventional modeling method in a short time.
3. The invention discloses a reverse modeling method of a turboshaft engine based on test data, which realizes reverse modeling of the turboshaft engine based on the test data, can improve the precision of a model in test evaluation of the turboshaft engine, improve the performance prediction precision of the turboshaft engine, improve the effectiveness identification rate of test collected data, improve the high-altitude performance evaluation precision of the test, and solve the problems of related engineering of the turboshaft engine in engineering application.
Drawings
FIG. 1 shows a flow chart of an embodiment of a method for reverse modeling of a turboshaft engine based on experimental data.
Fig. 2 shows a flow chart of parameter trial and error of an embodiment.
Fig. 3 shows a process diagram of efficiency translation adjustment of an embodiment.
Fig. 4 shows a schematic process diagram of the rotational speed translation adjustment according to the embodiment.
Fig. 5 shows a process diagram of the co-working line adjustment of an embodiment.
Detailed Description
For a better understanding of the objects and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings and examples.
Example 1:
various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some instances, methods, procedures, components, and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present invention.
As shown in fig. 1, the reverse modeling method for the turboshaft engine based on the test data disclosed in this embodiment includes the following specific steps:
in step 1, turboshaft engine test data is analyzed and processed.
In this embodiment, the test data may be high altitude performance data acquired during installation or test of the turboshaft engine. The test data are converted to the target state, so that all data are unified, and the accuracy of the test data is guaranteed. The target state may be an international standard atmospheric plane state, an altitude simulation test state, etc., and a person skilled in the art may set the target state according to actual needs, which is not limited by the present invention.
Before the state conversion is carried out on the test data, the test data process of the plurality of test points can be preliminarily confirmed according to the test point layout of the plurality of test points in the test, the structural section of the turboshaft engine, the design report of the turboshaft engine, the specification of the turboshaft engine and other data assistance, the design index parameters of each part are analyzed and estimated, the continuity check of the same parameters of the engine in different throttling states is utilized, dead spots in the test data of the plurality of test points are eliminated, and the accuracy of the finally established target pneumatic thermodynamic model is ensured. The dead pixel can be a test point with obvious error or insufficient accuracy in test data.
As a typical example, the test data may include information relating to the operating state of the turboshaft engine in flight of a helicopter, such as turboshaft engine inlet physical air flow, gas turbine speed, fuel flow, compressor outlet temperature, output shaft power, and the like.
In step 2, screening the data in the test point data set to obtain a screened test point data set.
In the present embodiment, the data in the test point data set is filtered, and the filtering is performed based on the reynolds number index, the gas turbine relative conversion rotational speed, the number of throttle states, and the like of the data in the test point data set.
In step 2.1, data with the Reynolds number index larger than the Reynolds number threshold in the test point data set is selected to obtain a first test point data set.
In this implementation manner, the reynolds number threshold may be set according to the requirements of model accuracy, the number of test data, and the like, which is not limited by the present invention. For example, the reynolds number threshold is set to 0.7, so that the test data in the test point data set 1 can be ensured not to be influenced by the reynolds number factor, the test data in the first test point data set can directly reflect the pneumatic-thermal matching relationship inside the turboshaft engine, and meanwhile, the accuracy of the model can be ensured. The RNI index is calculated by formula (3).
Wherein: RNI Reynolds number index, Pt as total intake pressure at current test point, and PtrefFor reference total pressure, the value is 101.325kPa, RrefThe value is 287J/(kg K), R is the test point gas constant, TtrefFor reference total temperature, the value 288.15K, Tt is the total inlet air temperature at the current test point, μrefFor reference aerodynamic viscosity, the value is 1.844E-05, μ is the test point aerodynamic viscosity.
In step 2.2, selecting the gas turbine relative conversion rotating speed in the test point data set 1 to be larger than the rotating speed threshold value, and obtaining a test point data set 2.
In this implementation, the rotation speed threshold is set according to the model precision, the number of test data, and the like, which is not limited by the present invention. For example, the rotational speed threshold is set to 0.9, the turboshaft engine is in a high-load, high-efficiency and high-power state, and sensors and the like on the turboshaft engine are in a higher-precision measurement interval, so that the relative error of the determined test data in the test point data set 2 can be reduced, and the precision of the model can be ensured. The gas turbine relative reduced rotation speed is calculated by equation (4).
Wherein: n is a radical of1corGas turbine reduced speed, N1，ISA，SLS，1.0For the design rotational speed.
In step 2.3, the test points with more throttle state data corresponding to the test point data set 2 are selected to obtain the screening test point data set 3.
In this implementation, the state data amount is set according to the model precision, the number of test data, and the like, which is not limited by the present invention.
In a typical example, data volumes of test data of test points covered by different throttling states are counted, the data volumes of the different throttling states are sorted according to the sequence of the data volumes from large to small, and a state data volume threshold is determined according to the data volume of one or more throttling states sorted before. So as to select the test data of the test points covered by the previous throttle state or throttle states in the test point data set 2, and obtain the screening test point data set 3.
By the mode, the model precision is ensured, and meanwhile, the test data are kept as much as possible, so that the subsequent calibration process can have enough test data, the calibration precision is improved, and the model precision is further improved.
In step 3, sequentially performing parameter trial and error on a plurality of trial and error iteration parameters in the aerodynamic thermodynamic model according to the test point data to obtain an engine initial model;
in a typical example, in step 3, model-adjustable parameter iteration trial and error is carried out according to the sequence of the converted air flow, the outlet temperature of the combustion chamber, the air compressor and the power turbine part, and the specific implementation method is as follows:
TABLE 1 parameter matching criterion
| Numbering | Testing parameters to be matched | Trial and error iteration parameter |
| 1 | Measured physical air flow | Inlet converted |
| 2 | Measured fuel flow | Outlet temperature of |
| 3 | Actual measurement of compressor outlet temperature | Efficiency of |
| 4 | Measured shaft power | Power turbine efficiency |
1. And (4) testing and assembling the inlet converted flow in the aerodynamic model according to the actually measured physical air flow.
2. And (4) according to the actually measured fuel flow, testing and collecting the outlet temperature of the combustion chamber in the pneumatic thermodynamic model.
3. And (4) testing the efficiency of the air compressor in the aerodynamic thermodynamic model according to the actually measured outlet temperature of the air compressor.
4. And testing and assembling the efficiency of the power turbine in the aerodynamic thermodynamic model according to the actually measured output shaft power.
Performing parameter trial and error on matching criteria of different test data according to the parameter matching criteria in the table 1, and when the number of trial and error parameters is smaller than the number of parameters to be matched in the test, performing iterative trial and error according to the adjustable parameters of the model to obtain a trial and error result; and when the number of the trial and error parameters is larger than the number of the parameters to be matched in the test, judging the range of the initial selection reasonable value of each parameter according to the trial and error results of a plurality of parameters by using the data assistance in the step 1.
In this implementation manner, trial and error are sequentially performed according to the above sequence, and trial and error of the next step can be performed only after trial and error success is ensured, and the parameter trial and error flow is shown in fig. 2. The successful trial and achievement can mean that parameters in the pneumatic thermodynamic model obtained through trial and achievement can enable the pneumatic thermodynamic model to simultaneously meet the flow continuity equation, the energy conservation equation, the power balance equation, the rotating speed matching and other criteria.
Because the actually measured parameter and the trial and error iteration parameter have a monotonous or single-value corresponding relationship, the trial and error iteration parameter corresponding to the actually measured parameter can be found out according to the change of the actually measured parameter. The measured fuel flow is used for carrying out trial and error on the outlet temperature of the combustion chamber in the aerodynamic thermodynamic model. Since a greater measured fuel flow rate indicates more fuel is added to the combustion chamber of the turboshaft engine, a higher outlet temperature of the combustion chamber is achieved by combusting the fuel in the combustion chamber. Presetting a combustion chamber outlet temperature, calculating the predicted fuel flow through a pneumatic thermodynamic model, and judging whether the predicted fuel flow is the same as the actually measured fuel flow. And when the predicted fuel flow is different from the actually measured fuel flow, modifying parameters related to the outlet temperature of the combustion chamber in the pneumatic thermodynamic model, and calculating the predicted fuel flow according to the pneumatic thermodynamic model after the parameters are modified. And when the predicted fuel flow is the same as the actually measured fuel flow and the modified parameters of the aerodynamic thermodynamic model simultaneously meet the flow continuity equation, the energy conservation equation, the power balance equation, the rotating speed matching and other criteria, determining that the trial and error is successful and obtaining the primary model of the engine. The other parameter trial and error processes are similar and will not be described herein.
It should be understood that the trial and error process described above is only an example provided by the present invention, and those skilled in the art can set the trial and error process according to actual needs, and the present invention is not limited to this.
In step 4, the characteristics of the general component are adjusted based on the preliminary model and the throttle state test data to obtain a calibrated mathematical model.
In a possible implementation manner, based on the component characteristics of the universal turboshaft engine, the pneumatic thermodynamic model after test and collection is calibrated through at least one of efficiency translation adjustment, rotating speed translation adjustment and common working line adjustment, so that the calibrated pneumatic thermodynamic model is obtained.
In one possible implementation, the efficiency translation adjustment may include: and carrying out efficiency translation adjustment on at least one part characteristic according to the actually detected distribution of the throttling state efficiency so as to calibrate the trial and error aerodynamic model and obtain the calibrated aerodynamic model. In the process of performing the efficiency translation adjustment of at least one component characteristic, the cyclic reference point is not changed, and the cyclic state point may include a test point covered by a throttling state with the largest data amount in the screening test point data set.
Fig. 3 shows a process diagram of the efficiency shift adjustment according to the present embodiment. As shown in fig. 3, the plurality of points shown in the figure, which are not connected together by a line, represent the actually detected throttle state efficiency, and the plurality of points connected together by a line represent the throttle state efficiency curve calculated according to the aerodynamic model after the trial and error. And keeping the cyclic reference point unchanged, and calibrating the pneumatic thermodynamic model for multiple times through multiple efficiency translation adjustment until the calculated throttling state efficiency curve is adjusted to a distribution state approaching the actually detected throttling state efficiency to obtain the finally calibrated pneumatic thermodynamic model.
In one possible implementation, the rotational speed translation adjustment may include: and according to the actually detected distribution of the rotating speed, carrying out rotating speed translation adjustment on at least one part characteristic so as to calibrate the trial and error aerodynamic model and obtain the calibrated aerodynamic model. Wherein, in the process of carrying out the rotational speed translation adjustment of at least one component characteristic, the corresponding component rotational speed line position is unchanged.
Fig. 4 is a schematic diagram showing a process of the rotational speed translation adjustment according to the present embodiment. As shown in fig. 4, the points shown in the figure which are not connected together by a line represent the actually detected rotational speed, and the points connected together by a line represent the rotational speed curve calculated according to the tried-and-made aerodynamic model. Keeping the position of the rotating speed line of the component unchanged, and calibrating the pneumatic thermodynamic model for multiple times through multiple rotating speed translation adjustment until the rotating speed curve obtained through calculation is adjusted to be close to the actually detected rotating speed distribution state, so as to obtain the finally calibrated pneumatic thermodynamic model.
In one possible implementation, the adjusting of the common working line may include: and according to the relation between the determined pressure ratio and the flow of the air compressor, carrying out up-and-down adjustment on the common working line through variable geometric adjustment at different rotating speeds so as to calibrate the trial-and-error aerodynamic thermodynamic model and obtain the calibrated aerodynamic thermodynamic model.
Fig. 5 is a schematic diagram showing a process of the adjustment of the common working line according to the present embodiment. As shown in fig. 5, the points shown in the figure which are not connected together by a line represent the actually detected joint working line when the components of the turboshaft engine are working together, and the joint working line is the compressor pressure ratio-flow rate line. Represented by a plurality of points connected together by lines is a common working line calculated from the tried and made aerodynamic model. And calibrating the pneumatic thermodynamic model for multiple times through multiple times of variable geometric adjustment at different rotating speeds until the common working line obtained by calculation is adjusted to be close to the actually detected common working line, and obtaining the finally calibrated pneumatic thermodynamic model.
In step 5, correcting the turboshaft engine reverse construction model based on the test data constructed in the step 4 by using the part characteristics calibrated in the step 4 and combining a correction method of full-envelope error information, and further improving the model precision to obtain a target model; the method for correcting the full-envelope error information comprises a Reynolds number correction method and a gap correction method.
In a possible implementation manner, the corrected aero-thermodynamic model may be modified by using at least one of a reynolds number modification manner and a clearance modification manner according to an aircraft envelope (a flight envelope, which refers to a closed geometric figure that represents an aircraft flight range and an aircraft use restriction condition with parameters such as a flight speed, an altitude, an overload, and an ambient temperature as coordinates) corresponding to the turbine engine, so as to obtain the target model.
In one possible implementation, the reynolds number correction mode includes:
acquiring errors and inlet pressure of actually detected test data of a plurality of test points of the turboshaft engine, and determining an oil consumption rate parameter corresponding to the inlet pressure;
and when the correlation between the error and the inlet pressure distribution is determined and the condition that the oil consumption rate parameter is lower than the test value is presented under the condition of low inlet pressure, correcting the calibrated aerodynamic thermodynamic model in a Reynolds number correction mode to obtain the target aerodynamic thermodynamic model. Wherein the calculated fuel consumption is calculated according to the corrected aerodynamic model.
In this implementation, the correlation coefficient of the error with the inlet pressure profile may represent the degree to which the error is correlated with the inlet pressure profile, with the greater the magnitude of the correlation coefficient, the more pronounced the correlation of the error with the inlet pressure profile. The corrected aerodynamic thermodynamic model is corrected in a Reynolds number correction mode, so that the efficiency of a compression part in the corrected aerodynamic thermodynamic model can be reduced when the inlet pressure is lower than a pressure threshold, and the amplitude of reducing the efficiency of the compression part can be adjusted according to the change condition of an aircraft envelope before and after model correction.
In one possible implementation, the gap correction method includes:
acquiring actually detected errors and inlet temperatures of test data of a plurality of test points of the turboshaft engine;
and when the correlation between the error and the inlet temperature distribution is determined, correcting the calibrated aerodynamic model in a clearance correction mode to obtain a target aerodynamic model.
In this implementation, the correlation coefficient of the error with the inlet temperature distribution may represent the degree of correlation of the error with the inlet temperature distribution, and the larger the value of the correlation coefficient, the more significant the correlation of the error with the inlet temperature distribution. The corrected aerodynamic thermodynamic model is corrected in a clearance correction mode, and the correction quantity of the blade tip clearance of the turboshaft engine can be adjusted. The amplitude of the correction amount for adjusting the blade tip clearance can be adjusted according to the change condition of the aircraft envelope before and after model correction and the like.
Step 6: according to the target model in the step 5, the precision of the model in the test evaluation of the turboshaft engine is improved, the performance prediction precision of the turboshaft engine is improved, the effectiveness identification rate of test acquisition data is improved, the high altitude performance evaluation precision of the test is improved, and the problems of related engineering of the turboshaft engine are solved in engineering application.
In the step 5, a turboshaft engine reverse construction model based on test data is adopted, the simulation error of main performance parameters in the full envelope range of the turboshaft engine is improved to be within 1% from about 5%, the performance prediction level of the turboshaft engine can be greatly improved, the test data validity can be judged, and the problem of relevant engineering in the application field of the turboshaft engine is solved.
In the modeling method of the turboshaft engine provided by the embodiment, the state of the test data of a plurality of test points of the turboshaft engine is converted to obtain a test point data set in a target test state; screening data in the test point data set to obtain a screened test point data set; sequentially carrying out parameter trial and error on a plurality of trial and error iteration parameters in the aerodynamic thermodynamic model according to a plurality of actually measured parameters which are actually detected to obtain the trial and error aerodynamic thermodynamic model; calibrating the trial and error aerodynamic thermodynamic model to obtain a calibrated aerodynamic thermodynamic model; and correcting the corrected aerodynamic thermodynamic model to obtain a target aerodynamic thermodynamic model. The period for constructing the target pneumatic thermodynamic model of the turboshaft engine is short, and the error of the constructed target pneumatic thermodynamic model of the turboshaft engine is small and the precision is high.
The above detailed description is intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above detailed description is only exemplary of the present invention and is not intended to limit the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A turboshaft engine reverse modeling method based on test data is characterized in that: comprises the following steps of (a) carrying out,
step 1: analyzing and processing test data of the turboshaft engine; checking bad points in data by using continuity check of the same parameters of the turboshaft engine under different throttling states; converting the air flow and the rotating speed of the gas turbine to the state of the international standard atmospheric sea level, and converting the other section parameters to the uniform test state;
step 2: in order to ensure the precision of reversely constructing a turboshaft engine model, selecting an engine test state point; the engine test state point selection method comprises the following steps: selecting test point data by adopting Reynolds number index screening, ensuring that the test data simply reflects the pneumatic-thermal matching relation in the engine, and eliminating the influence of Reynolds number; selecting high-state test data through engine state screening to ensure that a test point selected as a preliminary mathematical model of heat has a higher working state, the engine is under a higher load, the sensor is in a higher-precision measurement interval, and the relative error of each measured parameter is smaller; selecting test points with more throttle states by adopting throttle state screening, ensuring that more available data exist during subsequent calibration of the reversely constructed turboshaft engine model, and the more data, the more beneficial the final precision of the subsequently reversely constructed turboshaft engine model;
step 3, establishing a preliminary turboshaft engine model through parameter iteration trial and error by using the test data of the engine test state points selected in the step 2;
and 4, step 4: calibrating the model by utilizing the preliminary turboshaft engine model and the throttling state test data established in the step 3 and adjusting the characteristics of the universal part to obtain the characteristics of the calibrated part and the turboshaft engine model, and constructing the turboshaft engine model based on the test data; the general component characteristic adjusting method comprises an efficiency adjusting method, a rotating speed adjusting method and a common working line adjusting method;
step 5, correcting the turboshaft engine reverse construction model based on the test data constructed in the step 4 by using the part characteristics calibrated in the step 4 and combining a correction method of full-envelope error information, and further improving the model precision to obtain a target model; the method for correcting the full-envelope error information comprises a Reynolds number correction method and a gap correction method.
2. The reverse modeling method for the turboshaft engine based on the experimental data as claimed in claim 1, characterized in that: and 6, according to the target model in the step 5, improving the precision of the model in the test evaluation of the turboshaft engine, improving the performance prediction precision of the turboshaft engine, improving the effectiveness identification rate of test acquisition data, improving the high-altitude performance evaluation precision of the test, and solving the related engineering problem of the turboshaft engine in engineering application.
3. A method of reverse modeling a turboshaft engine based on experimental data according to claim 1 or 2, characterized in that: the step 1 is realized by the method that,
carrying out preliminary confirmation on test data by using data assistance, and analyzing and pre-estimating design index parameters of each part; checking dead pixels in data by using continuity check of the same parameters of the engine under different throttling states; converting the air flow and the rotating speed of the gas turbine to the state of the international standard atmospheric sea level, and converting the other section parameters to the uniform test state;
the data assistance comprises a test point layout, an aircraft engine structure section, a design report and a specification.
4. A method of reverse modeling of a turboshaft engine based on experimental data according to claim 3, characterized in that: the step 2 is realized by the method that,
step 2.1: selecting test point data by adopting Reynolds number index screening, ensuring that the test data simply reflects the pneumatic-thermal matching relation in the engine, and eliminating the influence of Reynolds number;
reynolds number index screening is carried out on the test data of the turboshaft engine in the step 1, and the test point set 1 with the RNI index larger than a preset screening threshold is selected as a to-be-selected test point set, so that the test data can be ensured to simply reflect the pneumatic thermal matching relation in the engine, and the influence of the Reynolds number is eliminated; the RNI index is calculated by formula (1);
wherein: RNI Reynolds number index, Pt as total intake pressure at current test point, and PtrefIs referred to as total pressure, RrefIs used as reference gasNumber, R is the gas constant at the test point, TtrefIs the reference total temperature Tt is the intake total temperature mu of the current test pointrefIs the reference aerodynamic viscosity, mu is the test point aerodynamic viscosity;
step 2.2: selecting high-state test data through engine state screening to ensure that a selected test point has a higher working state, the engine is under a higher load, the sensor is in a higher-precision measurement interval, and the relative error of each measured parameter is smaller;
screening the engine state of the test data of the turboshaft engine in the step 2.1, selecting a test point set 2 with the relative conversion rotating speed of the gas turbine larger than a preset screening threshold value, ensuring that the selected test point serving as a preliminary mathematical model of heat power has a higher working state, the engine is in a higher load, the sensor is in a higher-precision measurement interval, and the measured parameters have smaller relative errors; the relative conversion rotating speed of the gas turbine is calculated by the formula (2);
wherein: n is a radical of1corGas turbine reduced speed, N1，ISA，SLS，1.0Designing the rotating speed;
step 2.3: selecting test points with more throttle states by adopting throttle state screening, ensuring that more available data exist during subsequent calibration of reversely constructed turboshaft engine models, and the more data, the more beneficial the final precision of the subsequently reversely constructed turboshaft engine mathematical models;
and (3) screening the engine throttling state of the test data of the turboshaft engine in the step (2.2), selecting a test point set 3 with more throttling states, wherein more available data are provided during subsequent calibration of the reversely constructed turboshaft engine model, and the more data are, the more beneficial the final precision of the subsequently reversely constructed turboshaft engine model is.
5. The reverse modeling method for the turboshaft engine based on the experimental data as claimed in claim 4, characterized in that: the step 3 is realized by the method that,
and (3) matching the test data of the engine test state points selected in the step (2) in sequence, and sequentially performing parameter trial and error on a plurality of trial and error iteration parameters in the aerodynamic thermodynamic model to obtain a primary turboshaft engine model.
6. The reverse modeling method for the turboshaft engine based on the experimental data as claimed in claim 5, characterized in that: in step 3, carrying out model adjustable parameter iteration trial and error according to the sequence of the converted air flow, the outlet temperature of the combustion chamber, the air compressor and the power turbine part, and specifically realizing the method as follows:
according to the actually measured physical air flow, performing trial and error on the air flow converted by an inlet in the aerodynamic model;
according to the actually measured fuel flow, testing and collecting the outlet temperature of the combustion chamber in the aerodynamic thermodynamic model;
according to the actually measured outlet temperature of the gas compressor, the efficiency of the gas compressor in the pneumatic thermodynamic model is tried and found;
according to the actually measured shaft power, testing and collecting the efficiency of the power turbine in the pneumatic thermodynamic model;
and obtaining a primary turboshaft engine model after the sequential trial and completion.
7. The reverse modeling method for the turboshaft engine based on the experimental data as claimed in claim 6, characterized in that: step 4, the method is realized by the following steps,
based on the preliminary turboshaft engine model established in the step 3, selecting part characteristics according to the number of stages, the total pressure ratio and the flow rate, and calibrating the throttling state to obtain calibrated part characteristics; the general component characteristic adjusting method comprises an efficiency adjusting method, a rotating speed adjusting method and a common working line adjusting method; the efficiency adjusting method comprises the steps of performing efficiency translation adjustment on the characteristics of the selected part according to the efficiency distribution of the throttling state actually measured in the test, and keeping a circulating reference point unchanged during adjustment; the rotating speed adjusting method is used for adjusting the rotating speed in the component characteristics according to a rotating speed translation method, and only the corresponding rotating speed value is changed without changing the position of a rotating speed line of the component during adjustment; adjusting a common working line of the components, performing variable geometric adjustment according to the relation between the pressure ratio and the air flow of the air compressor measured in an experiment, and performing up-and-down adjustment of the common working line at different rotating speeds; the method for adjusting the characteristics of the universal component is used for calibrating the throttling state to obtain the characteristics of the calibrated component, and the reverse construction model of the turboshaft engine based on the test data is constructed by utilizing the characteristics of the calibrated component.
8. The reverse modeling method for the turboshaft engine based on the experimental data as claimed in claim 7, characterized in that: step 5 the method is realized by the following steps,
correcting the turboshaft engine reverse construction model based on the test data constructed in the step 4 by using the characteristics of the parts calibrated in the step 4 and combining a correction method of full envelope error information, and further improving the model precision; before the precision of a turboshaft engine reverse construction model based on test data is further improved, model test deviation of overall parameters and pressure parameters is defined as relative error, and model test deviation of temperature is defined as absolute error.
9. The reverse modeling method for the turboshaft engine based on the experimental data as claimed in claim 8, characterized in that: the correction method of the full envelope error information comprises a Reynolds number correction method and a clearance correction method;
the Reynolds number correction method comprises the following steps: observing the distribution relation of the error of each point along with the engine inlet pressure, introducing Reynolds number correction if the error magnitude and the pressure distribution show obvious correlation and the condition that the oil consumption rate parameter is lower than a test value is shown under the condition of low inlet pressure, properly reducing the efficiency of a compression part when the engine inlet pressure is lower, wherein the reduction amplitude is determined according to experience and the distribution improvement condition of the full envelope error;
the clearance correction method comprises the following steps: observing the distribution relation of the error of each point along with the temperature of an inlet of the engine, introducing clearance correction if the error shows obvious correlation along with the temperature, specifically adjusting the correction quantity of the clearance correction of the top end of the blade designed in the pneumatic thermodynamic cycle program, wherein the adjustment amplitude is determined according to experience and the distribution improvement condition of the full envelope error.
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