CN114818112A - Post-processing method for integrated VB-Matlab type five-hole probe - Google Patents
Post-processing method for integrated VB-Matlab type five-hole probe Download PDFInfo
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Abstract
The invention discloses an integrated VB-Matlab type five-hole probe post-processing method, which belongs to the field of field measurement data processing and comprises the following steps: acquiring a pressure value, an inflow parameter and an environmental parameter of each hole detected by a five-hole probe; interpolating the calibration file by using a three-dimensional interpolation method, and fitting to obtain the calibration file under all Mach numbers in a fixed interval; performing rough step estimation on the mach number of the incoming flow, and obtaining flow field parameters of the air flow by utilizing a calibration file under the rough step estimation mach number; comparing a calibration file under the Mach number estimated in a coarse step with the incoming flow Mach number to obtain flow field parameters; the invention solves the problem of post-processing calculation of the five-hole probe, integrates the VB human-computer interaction interface and the Matlab rapid data processing capability by utilizing the VB and the Matlab and the interface between the VB and the Matlab, and meets the requirements of professionals in the industry on processing flow field parameters acquired by the five-hole pressure probe.
Description
Technical Field
The invention belongs to the field of field measurement data processing, and relates to an integrated VB-Matlab type five-hole probe post-processing method which is suitable for the post-processing process of flow field measurement data of gas dynamics, wind tunnel tests, aircraft design and the like.
Background
The five-hole probe is the most commonly used measuring instrument in current flow field measurement and control, and has the characteristics of low manufacturing cost, high precision, strong applicability and the like; in addition, the Mach number of the measuring point, the flow velocity of the measuring point, the airflow angle of the measuring point and the airflow pressure which cannot be obtained by other measuring and controlling instruments can be obtained by the five-hole probe in the measuring process, so that the five-hole probe is a preferred measuring instrument for personnel in the industry. However, the wind tunnel has high cost, multiple working conditions of test pieces and long experimental time during experiments, and some calculation methods cannot be integrated into five-hole probe calculation software, so that the post-processing of the measurement data of the five-hole probe every time is very important. The invention solves the problem of post-processing calculation of the five-hole probe. The invention combines the VB human-computer interaction interface and the Matlab rapid data processing capability by utilizing VB and Matlab and interfaces between the VB and the Matlab, and meets the requirements of professionals in the industry on processing flow field parameters acquired by a five-hole pressure probe.
The calculation angle range of the existing linear interpolation method is +/-30 degrees, and only a calibration curve under a single Mach number can be used in calculation. Therefore, the linear interpolation method has no good adaptability to the flow field with Mach number change, and when the Mach number of the incoming flow exceeds a certain range of the calibrated speed, a calculation result has a large error.
The calculation angle range of the existing partition expansion is +/-60 degrees, and only one calibration curve under Mach number is used in calculation. Compared with the linear interpolation method, the calculation angle range of the five-hole probe is improved, but the adaptability to the Mach number change is not high. When the difference between the incoming flow mach number and the calibration mach number is large, higher calculation accuracy cannot be guaranteed at all.
Disclosure of Invention
In order to solve the above problems, the present invention provides the following technical solutions: a post-processing method of an integrated VB-Matlab type five-hole probe comprises the following steps:
s1, acquiring the pressure value, inflow parameter and environment parameter of each hole detected by the five-hole probe;
s2, interpolating the calibration files by using a three-dimensional interpolation method, and fitting to obtain the calibration files under all Mach numbers in a fixed interval;
s3, performing coarse step estimation on the Mach number of the incoming flow, and obtaining flow field parameters of the air flow by using a calibration file under the Mach number of the coarse step estimation;
and S4, comparing the calibration file under the Mach number of the rough step estimation with the incoming flow Mach number to obtain the flow field parameters.
Further: the three-dimensional interpolation method comprises a three-dimensional linear interpolation method, a three-dimensional Newton quadratic interpolation method and a three-dimensional least square interpolation method.
Further: the three-dimensional least square interpolation method is used for interpolating the calibration files to obtain the calibration files under all Mach numbers in a fixed interval as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
performing least square fitting on characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach characteristic curve and the Mach to obtain the relation between the characteristic values of the Mach and the position;
and obtaining calibration files under all Mach numbers in a fixed interval through least square fitting interpolation.
Further: the process of interpolating the calibration file by using the three-dimensional linear interpolation method to obtain the calibration files under all Mach numbers in the fixed interval is as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
linear fitting is carried out on characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach number characteristic curve and the Mach number to obtain the relation between the Mach number and the characteristic value of the position;
and obtaining calibration files under all Mach numbers in the Mach number interval by a three-dimensional linear interpolation method.
Further, the process of interpolating the calibration file by using the three-dimensional newton quadratic interpolation method to obtain the calibration files at all mach numbers within the fixed interval is as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
carrying out Newton quadratic interpolation fitting on the characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach number characteristic curve and the Mach number to obtain the relation between the characteristic values of the Mach number and the position;
and obtaining calibration files under all Mach numbers in the Mach number interval through three-dimensional Newton quadratic interpolation.
Further, the fixed interval is: 0.2 to 0.8.
Further, the process of obtaining the flow field parameter by comparing the calibration file under the rough step Mach number with the incoming flow Mach number is as follows:
performing initial calculation on the incoming flow parameters through the roughly estimated Mach number to obtain a calculated Mach number and the roughly estimated Mach number, and outputting a result of performing initial calculation on the incoming flow parameters through the roughly estimated Mach number to obtain flow field parameters when the difference between the Mach number and the roughly estimated Mach number is one ten thousandth or less;
and when the difference between the Mach number and the roughly estimated Mach number is more than one ten thousandth, repeating the initial calculation process by taking the calibration file corresponding to the first Mach number calculation as a reference until the difference between the calculated Mach number and the Mach number corresponding to the calibration file is one thousandth, and outputting a result of oscillation approaching a true value through continuous iterative calculation to obtain the flow field parameters.
The integrated VB-Matlab type five-hole probe post-processing method provided by the invention has the following advantages: the invention solves the problem of post-processing calculation of the five-hole probe, integrates the VB human-computer interaction interface and the Matlab rapid data processing capability by utilizing the VB and the Matlab and the interface between the VB and the Matlab, and meets the requirements of professionals in the industry on processing flow field parameters acquired by the five-hole pressure probe.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1(a) is a 0.2Ma angular calibration plot; (b) an angle calibration plot of 0.5Ma, (c) an angle calibration plot of 0.8 Ma;
FIG. 2 is a graph of angle calibration curves for three Mach numbers placed in the same coordinate;
FIG. 3 is a graph showing four boundary points obtained by the least squares method;
FIG. 4 is an interface diagram of a module employing the method of the present application;
FIG. 5 is a schematic diagram of an exemplary process for three-dimensional least squares interpolation;
FIG. 6 is a block diagram of a module calculation process;
FIG. 7 is a diagram of a conventional linear interpolation process;
FIG. 8 is a schematic view of a five-well probe zone calculation zone;
FIG. 9 is a schematic diagram of a three-dimensional linear interpolation process.
Detailed Description
It should be noted that, in the case of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other, and the present invention will be described in detail with reference to the accompanying drawings and embodiments.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. Any specific values in all examples shown and discussed herein are to be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In the description of the present invention, it is to be understood that the directions or positional relationships indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the directions or positional relationships shown in the drawings for the convenience of description and simplicity of description, and that these directional terms, unless otherwise specified, do not indicate and imply that the device or element so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be considered as limiting the scope of the invention: the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
Spatially relative terms, such as "above … …," "above … …," "above … … surface," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.
A post-processing method of an integrated VB-Matlab type five-hole probe comprises the following steps:
s1, acquiring the pressure value, inflow parameter and environment parameter of each hole detected by the five-hole probe;
s2, interpolating the calibration files by using a three-dimensional interpolation method, and fitting to obtain the calibration files under all Mach numbers in a fixed interval;
s3, performing coarse step estimation on the Mach number of the incoming flow, and obtaining flow field parameters of the air flow by using a calibration file under the Mach number of the coarse step estimation;
and S4, comparing the calibration file under the Mach number of the rough step estimation with the incoming flow Mach number to obtain the flow field parameters.
Further: the process of obtaining the flow field parameters by comparing the calibration file under the rough step Mach number with the incoming flow Mach number is as follows:
performing initial calculation on the incoming flow parameters through the roughly estimated Mach number to obtain a calculated Mach number and the roughly estimated Mach number, and outputting a result of performing initial calculation on the incoming flow parameters through the roughly estimated Mach number to obtain flow field parameters when the difference between the Mach number and the roughly estimated Mach number is one ten thousandth or less;
and when the difference between the Mach number and the roughly estimated Mach number is more than one ten thousandth, repeating the initial calculation process by taking the calibration file corresponding to the first Mach number calculation as a reference until the difference between the calculated Mach number and the Mach number corresponding to the calibration file is one thousandth, and outputting a result of oscillation approaching a true value through continuous iterative calculation to obtain the flow field parameters.
Further, the three-dimensional interpolation method comprises a three-dimensional linear interpolation method, a three-dimensional Newton quadratic interpolation method and a three-dimensional least square interpolation method.
Further, the three-dimensional least square interpolation method interpolates the calibration file to obtain the calibration files under all mach numbers in a fixed interval as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
performing least square fitting on characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach characteristic curve and the Mach to obtain the relation between the characteristic values of the Mach and the position;
and obtaining calibration files under all Mach numbers in a fixed interval through least square fitting interpolation.
Further: the process of interpolating the calibration file by using the three-dimensional linear interpolation method to obtain the calibration files under all Mach numbers in the fixed interval is as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
linear fitting is carried out on characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach number characteristic curve and the Mach number to obtain the relation between the Mach number and the characteristic value of the position;
and obtaining calibration files under all Mach numbers in the Mach number interval by a three-dimensional linear interpolation method.
Further: the process of interpolating the calibration file by using the three-dimensional Newton quadratic interpolation method to obtain the calibration files under all Mach numbers in the fixed interval is as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
carrying out Newton quadratic interpolation fitting on the characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach number characteristic curve and the Mach number to obtain the relation between the characteristic values of the Mach number and the position;
and obtaining calibration files under all Mach numbers in the Mach number interval through three-dimensional Newton quadratic interpolation.
Further: the fixed interval is as follows: 0.2 to 0.8.
Calibrating a plurality of Mach numbers at equal intervals in the fixed interval; if we determine that the probe is used in a Mach number range of 0.2 to 0.8Ma, then 0.2Ma, 0.5Ma, 0.8Ma are calibrated (these are also already said). This calibration is a calibration process, and the probe is placed in a calibration wind tunnel to complete the calibration, and fig. 1(a) is a 0.2Ma angle calibration curve (i.e., an angle calibration file); (b) angle calibration plot of 0.5Ma, (c) angle calibration plot of 0.8 Ma.
The calibration file refers to a file for importing computing software during computing;
the calibration curve is a curve made when the calibration points are shown in a curved form; both are things that are one, but in different situations, different habitual calls.
Since the calibration curves for the total static pressure coefficient are also similar, this specification is not to be interpreted.
The characteristic values (K) of the same pitch angle alpha and deflection angle beta positions of the calibrated Mach number characteristic curves are obtained α ，K β ，C Pt ，C Po ) A least squares fit is made to the mach number,
the angular calibration curves of the above three mach numbers are put in the same coordinate, as shown in fig. 2 below. The characteristic values (K) of the same pitch angle alpha and yaw angle beta are then calculated a ，K β ) A least squares fit is performed. Since there are 169 calibration points in each mach number calibration file, 169 least square fits are used, and the fitting process of the least square method (which is a mathematical method and is not only well known in the industry) finally fits 169 unary multiple functions, and the subsequent interpolation is to input the mach number in the 169 equations to obtain the interpolation value. This gives the entire interval [0.2, 0.8 ]]A calibration curve at each mach number can be obtained. Fig. 3 is a diagram showing a curve obtained by the least square method at four boundary points, and a calibration curve (the third plot from the left) of 0.6Ma interpolated.
The difference between the three-dimensional linear interpolation and the three-dimensional newton quadratic interpolation is the characteristic value (K) for the same pitch angle α and yaw angle β as compared with the least square method α ，K β ，C Pt ，C Ps ) And (3) carrying out three-dimensional linear interpolation or three-dimensional Newton quadratic interpolation, namely achieving the same effect by different means, namely obtaining calibration curves corresponding to all Mach numbers in the whole interval.
The invention can carry out post-processing calculation on the single-measuring-point data and the multi-measuring-point data in the file data import format, and most importantly, the invention provides a plurality of calculation methods during calculation, namely, the traditional calculation method and the newly developed calculation method.
FIG. 4 is an interface diagram of a module employing the method of the present application;
the data acquisition of the invention is that the data input and output module imports and exports the calculation file in the control area, the number of the measuring points is required to be written in the data import type before the calculation, and the data is in a dat format, thus ensuring the calculation speed and precision.
The analysis module is embodied in the calculation method, different calculation methods have different modules called in different calculation processes, the most basic bilinear interpolation module is called in a plurality of calculations, and in least square fitting, MartixVB.dll is called for the calculation of a matrix conveniently, and MartixVB.dll is also a control for calculating the matrix in VB software.
Compared with the traditional algorithm, the Mach number dimension is added into the calibration file in the invention to prepare for three-dimensional interpolation, an iterative calculation method is used for the three-dimensional interpolation, namely the oscillation process of the three-dimensional interpolation process, the calculated Mach number is used as a reference value to interpolate a calibration curve under the Mach number again, the calculation is performed again on the basis of the calibration file corresponding to the calculated Mach number, and the difference between the final calculation result and the previous calculation result is less than 0.1%, so the calculation precision is greatly increased. In addition, for the calculation method of the partition expansion, a calibration file of each of 5 partitions is included (a five-hole probe is changed into a four-hole probe for use because of the phenomenon of separation of one hole at the back when the angle is large), the calibration file of which partition is used is determined by comparing the pressure values of the holes during calculation, then the calculation is started, and linear interpolation or interpolation calculation under the same single Mach number in the three-dimensional case is also used during calculation of each partition.
It is worth noting that the method of matrix calculation is used in the three-dimensional least square method interpolation.
The invention provides three modes in a three-dimensional interpolation method (iteration is carried out during three-dimensional calculation because the Mach number corresponding to a calibration file and the difference value of the calculated Mach number are compared), a three-dimensional least square method is taken as an example, a plurality of Mach numbers with equal intervals in a range are firstly calibrated, and characteristic values (K) of the same characteristic curve, the same pitch angle alpha, the same deflection angle beta and the same position of each calibrated Mach number are obtained α ,K β ,C Pt ,C Ps ) Fitting with Mach number to obtain Mach number and K α ,K β ,C Pt ,C Ps The relationship of (1), namely a plurality of unary multiple functions, can obtain characteristic curves under all Mach numbers in the Mach number Ma interval through interpolation. FIG. 5 is a schematic diagram of an exemplary process for three-dimensional least squares interpolation;
calculating the angle coefficients according to the pressure values of the holes of the five-hole probe as follows:
wherein: p 1 、P 2 、P 3 、P 4 、P 5 Pressure values of five holes of the five-hole probe respectively, wherein
Mean pressure in the 1 st, 3 rd, 4 th and 5 th wells, K α Is a calibration coefficient of alpha direction, K β Is a beta direction calibration coefficient, C Pt For total pressure calibration factor, C Ps Is a static pressure calibration coefficient;
taking the main flow velocity of the incoming flow as 0.7Mac as an example, in the experiment, K is calculated by the formulas (1), (2) and (3) according to the pressure value of each hole of the five-hole probe α ，K β Taking a characteristic curve with the roughly estimated Mach number Ma (0) being 0.7 (optional) as a calibration file for primary calculation;
the angles and C of the incoming flow can be obtained by the formulas (4) and (5) by using a linear interpolation method Pt And C Ps According to C Pt 、C Ps Calculating Mach number Ma (1) calculated for the first time by using the obtained total pressure and static pressure, judging the difference value between Ma (1) and Ma (0), and if the difference value is not the sameIf the value is greater than one ten thousand, linear interpolation calculation is carried out again by using a characteristic curve corresponding to Ma (1), the Mach number Ma (2) calculated for the second time can be calculated by the same steps, then the difference value between the Ma (2) and the Ma (1) is compared, and the like is carried out until the difference value between the Mach number Ma (n) calculated for the nth time and the Mach number Ma (n-1) calculated for the n-1 time is less than one ten thousand, finally calculated flow field parameters such as each direction angle, total pressure, static pressure, Mach number and the like of the incoming flow are output, namely the real incoming flow Mach number is approximated by continuous oscillation, automatic acquisition and calibration are realized by using a computer, the process can be completed in a very short time, and the calculation flow is shown as the following figure 6.
The three-dimensional linear interpolation is similar to a three-dimensional Newton quadratic interpolation method and a three-dimensional least square method, but the three-dimensional linear interpolation only considers the three-dimensional interpolation between two Mach numbers, and the iterative computation steps are limited under the condition that the Mach number of a flow field is greatly changed; compared with the three-dimensional least square method, the three-dimensional Newton quadratic interpolation method has the defect that the smoothness of a fitting curve is not enough.
The calculation accuracy of the three-dimensional interpolation method is improved by 0.1-0.5% compared with the accuracy of the traditional bilinear interpolation method, wherein the calculation accuracy of the three-dimensional least square method is improved by at least 0.5% compared with the traditional method according to the current data.
When the method and the device are used, a user can select single-point calculation or file import calculation according to own requirements. When the file import calculation is used, the number of the measuring points needs to be written beside the file import calculation.
If single-point calculation is used, the pressure value of each hole of the five-hole probe is only required to be input into the main parameters, other parameters are input into the other parameters, and the parameters are clicked for confirmation. And then clicking the import calibration file to import the calibration file of the five-hole probe to calculate. And when the file is imported and calculated, the operation is not needed, and the measurement data of the five-hole probe can be directly imported, wherein the imported data format is as shown in the following, and the data format is still the atmospheric pressure, the atmospheric temperature, the total temperature of the incoming flow and the pressure value of the No. 1-5 holes of the five-hole probe from front to back.
Then, different calculation methods are selected, the calculation processes of the different calculation methods are different, and the calculation results are also different.
(1) The conventional method, namely bilinear interpolation (calculation angle ± 30 °), the calculation process is as shown in fig. 7 below. A, B, C, D is a calibration point, the middle point is a calculation value of the measuring point, the alpha and beta angles and the total static pressure coefficient of the measuring point are calculated by linear interpolation, the Mach number of the measuring point can be calculated according to the pressure values of the five holes, and the flow velocity of the measuring point can be obtained according to the temperature of the incoming flow, so that the parameters of the air flow are all obtained.
(2) And the partition expansion calculation mainly solves the limitation of the traditional five-hole probe on the calculation angle, the range of the alpha angle and the beta angle in the traditional calculation method is only +/-30 degrees, and the partition expansion can enable the alpha angle and the beta angle to reach +/-60 degrees. During calculation, according to the pressure values of different holes, the maximum value of the pressure values is searched, and bilinear interpolation is carried out in the corresponding area, so that specific flow field parameters are obtained. FIG. 8 is a schematic diagram of a calculation process of the method of the present application; pt represents total pressure, Ps represents static pressure;
(3) the method mainly solves the problem that a five-hole probe can only use a calibration file under one Mach number in calculation. The essence of the three-dimensional linear interpolation is a lagrange interpolation. The three methods fit and interpolate calibration files at different Mach numbers under the condition that the calibration files at a plurality of known Mach numbers are used. Therefore, iterative calculation can be performed during calculation, the incoming flow Mach number is calculated in the calibration curve under the roughly estimated Mach number, calculation is performed again according to the calculated calibration curve under the Mach number, and the like, so that the calculated Mach number and the Mach number corresponding to the calibration curve used for calculation are controlled within a certain deviation. FIG. 9 is a diagram of a conventional linear interpolation process;
according to the three-dimensional least square interpolation method, a curve with Mach number as a variable is fitted on the basis of calibration coefficients of different Mach numbers of the five-hole probe under the same angle. In this process, the calculation of the matrix is completed by a software call written by the VB, Matlab.
(4) Mixed calculation, which mainly refers to the combination use of five-hole probe partition expansion and three-dimensional linear interpolation, three-dimensional Newton quadratic interpolation and three-dimensional least square interpolation;
the traditional bilinear interpolation method cannot be used for different calculation methods. The new calculation method is an expansion on the basis of bilinear interpolation.
Different calibration files need to be imported for different calculation methods.
For the conventional calculation method calibration file format, the first row is the number of calibration points for each of the α and β angles, and the second row begins with calibration coefficients for each angle and the total pressure, static pressure coefficient, and angle of the calibration points.
For the calibration file of the partition expansion method, only the calibration files of different partitions need to be added below.
The calibration files of the three-dimensional linear interpolation, the three-dimensional Newton quadratic interpolation and the three-dimensional least square interpolation method are shown as follows, and Mach number dimensionality is added to facilitate interpolation calculation.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.
Claims (7)
1. A post-processing method of an integrated VB-Matlab type five-hole probe is characterized by comprising the following steps: the method comprises the following steps:
s1, acquiring the pressure value, inflow parameter and environment parameter of each hole detected by the five-hole probe;
s2, interpolating the calibration files by using a three-dimensional interpolation method, and fitting to obtain the calibration files under all Mach numbers in a fixed interval;
s3, performing coarse step estimation on the Mach number of the incoming flow, and obtaining flow field parameters of the air flow by using a calibration file under the Mach number of the coarse step estimation;
and S4, comparing the calibration file under the Mach number of the rough step estimation with the incoming flow Mach number to obtain the flow field parameters.
2. The integrated VB-Matlab type five-hole probe post-processing method according to claim 1, wherein the integrated VB-Matlab type five-hole probe post-processing method comprises the following steps: the three-dimensional interpolation method comprises a three-dimensional linear interpolation method, a three-dimensional Newton quadratic interpolation method and a three-dimensional least square interpolation method.
3. The integrated VB-Matlab type five-hole probe post-processing method according to claim 2, wherein the integrated VB-Matlab type five-hole probe post-processing method comprises the following steps: the three-dimensional least square interpolation method is used for interpolating the calibration files to obtain the calibration files under all Mach numbers in a fixed interval as follows:
calibrating a plurality of equidistant Mach numbers in a fixed interval;
performing least square fitting on characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach characteristic curve and the Mach to obtain the relation between the characteristic values of the Mach and the position;
and obtaining calibration files under all Mach numbers in a fixed interval through least square fitting interpolation.
4. The integrated VB-Matlab type five-hole probe post-processing method according to claim 2, wherein the integrated VB-Matlab type five-hole probe post-processing method comprises the following steps: the process of interpolating the calibration file by using the three-dimensional linear interpolation method to obtain the calibration files under all Mach numbers in the fixed interval is as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
linear fitting is carried out on characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach number characteristic curve and the Mach number to obtain the relation between the Mach number and the characteristic value of the position;
and obtaining calibration files under all Mach numbers in the Mach number interval by a three-dimensional linear interpolation method.
5. The integrated VB-Matlab type five-hole probe post-processing method according to claim 2, wherein the integrated VB-Matlab type five-hole probe post-processing method comprises the following steps: the process of interpolating the calibration file by using the three-dimensional Newton quadratic interpolation method to obtain the calibration files under all Mach numbers in the fixed interval is as follows:
calibrating a plurality of Mach numbers with equal intervals in a fixed interval;
carrying out Newton quadratic interpolation fitting on the characteristic values of the same pitch angle alpha, deflection angle beta and position of each calibrated Mach number characteristic curve and the Mach number to obtain the relation between the characteristic values of the Mach number and the position;
and obtaining calibration files under all Mach numbers in the Mach number interval through three-dimensional Newton quadratic interpolation.
6. The integrated VB-Matlab type five-hole probe post-processing method according to claim 1, wherein the integrated VB-Matlab type five-hole probe post-processing method comprises the following steps: the fixed interval is as follows: 0.2 to 0.8.
7. The integrated VB-Matlab type five-hole probe post-processing method according to claim 1, wherein the integrated VB-Matlab type five-hole probe post-processing method comprises the following steps: the process of obtaining the flow field parameters by comparing the calibration file under the rough step Mach number with the incoming flow Mach number is as follows:
performing initial calculation on the incoming flow parameters through the roughly estimated Mach number to obtain a calculated Mach number and the roughly estimated Mach number, and outputting a result of performing initial calculation on the incoming flow parameters through the roughly estimated Mach number to obtain flow field parameters when the difference between the Mach number and the roughly estimated Mach number is one ten thousandth or less;
and when the difference between the Mach number and the roughly estimated Mach number is more than one ten thousandth, repeating the initial calculation process by taking the calibration file corresponding to the first Mach number calculation as a reference until the difference between the calculated Mach number and the Mach number corresponding to the calibration file is one thousandth, and outputting a result of oscillation approaching a true value through continuous iterative calculation to obtain the flow field parameters.
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