Plane cascade wind tunnel test flow field quality evaluation method

Abstract

The invention belongs to the technical field of plane cascade wind tunnel tests, and particularly relates to a plane cascade wind tunnel test flow field quality evaluation method, which comprises the steps of 1, selecting flow field inspection quality inspection parameters; 2, evaluating the periodicity of an outlet flow field according to the flow field inspection quality inspection parameters of the outlet measurement plane MP2 of the plane cascade test piece; 3, calculating the mass flow average value of the MP1 flow field inspection quality inspection parameters of the inlet measurement plane of the plane cascade test piece; step 4, the incoming flow accuracy is evaluated by measuring the mass flow average value of the quality inspection parameters of the flow field inspection quality of the plane MP1 through the inlet of the plane cascade test piece; and 5, evaluating the uniformity of the flow field of the inlet according to the average mass flow value of the flow field inspection quality inspection parameters of the inlet measurement plane MP1 of the plane cascade test piece.

Description

Technical Field

[0001] This application belongs to the field of planar blade cascade wind tunnel testing technology, specifically relating to a method for evaluating the flow field quality in a planar blade cascade wind tunnel test. Background Technology

[0002] Planar blade cascade wind tunnel testing is a fundamental test for axial-flow turbomachinery. With the increasing demand for high-load airfoil design in modern aero-engines, the requirements for the reliability and accuracy of planar blade cascade wind tunnel tests are becoming increasingly stringent. The flow field quality in the planar blade cascade wind tunnel is a core factor determining the quality of planar blade cascade tests.

[0003] The flow field quality of an empty wind tunnel without planar cascade test specimens is a fundamental requirement for a planar cascade wind tunnel to function as a wind tunnel, and specific calibration requirements and evaluation indicators are usually specified in standards. The accuracy, uniformity, and periodicity of the inlet flow field, and the outlet flow field, are the core aspects of the flow field quality of a planar cascade wind tunnel with planar cascade test specimens. The special test section structure and limited test section dimensions inevitably lead to interference from the circumferential endwalls and spanwise sidewalls, allowing the planar cascade test specimens to only approximately simulate ideal planar cascade flow within a certain region.

[0004] While the Navigation Standard 20145-2014 provides some specifications for wind tunnel testing methods for planar blade cascades, its requirements for the flow field quality in such wind tunnels are very rudimentary. Specifically, the periodicity of the flow field in a planar blade cascade is primarily evaluated by manually observing the static pressure distribution on the in front wall of the cascade and the wake distribution behind the cascade in the middle two or three blade channels. This manual judgment method is highly random and variable, failing to provide a unified standard for evaluating flow field quality and hindering the comparison and correlation analysis of test data from different conditions, different blade cascades, and different wind tunnels.

[0005] Furthermore, the angle of attack of the blade cascade is mainly based on the ideal value set by the rotating disk in the wind tunnel test section. Navigation Standard 20145-2014 did not pay attention to or evaluate the accuracy of the actual angle of attack of the blade cascade, which seriously affected the accuracy of the blade cascade test data.

[0006] To improve the quality and usability of planar blade cascade wind tunnel test data, it is urgent to establish a comprehensive and unified quantitative evaluation method for the flow field quality of planar blade cascade wind tunnels. Summary of the Invention

[0007] The purpose of this application is to provide a method for evaluating the flow field quality in a planar cascade wind tunnel test. This method comprehensively and quantitatively evaluates the flow field quality in a planar cascade wind tunnel test from three dimensions: incoming flow accuracy, inlet flow field uniformity, and outlet flow field periodicity. This aims to reduce the uncertainty of planar cascade wind tunnel tests and promote the continuous standardization and refinement of existing planar cascade wind tunnel test technologies.

[0008] The technical solution of this application is:

[0009] A method for evaluating the flow field quality in a planar blade cascade wind tunnel test includes:

[0010] Step 1: Select flow field inspection quality inspection parameters This includes the inlet Mach number of the planar blade cascade test specimen at 50% blade height, measured on the inlet measurement plane MP1. Intake angle And the exit Mach number of the exit measurement plane MP2 at 50% blade height. Exhaust angle ;

[0011] Step 2: Measure the flow field at the outlet of the planar blade cascade test specimen to check the quality parameters of the plane MP2. To evaluate the periodicity of the outlet flow field;

[0012] Step 3: Calculate the flow field parameters for the MP1 inlet measurement plane of the planar blade cascade test specimen to check the quality. The average mass flow rate;

[0013] Step 4: Use the inlet of the planar blade cascade test specimen to measure the flow field in plane MP1 to check the quality inspection parameters. The average mass flow rate is used to evaluate the accuracy of the incoming flow.

[0014] Step 5: Measure the MP1 flow field at the inlet of the planar blade cascade test specimen to check the quality inspection parameters. The average mass flow rate is used to evaluate the uniformity of the inlet flow field.

[0015] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, the blade passage of the planar cascade test specimen is defined as follows:

[0016] From bottom to top, the blades of the planar blade cascade test specimen are defined sequentially as follows: blade number [number], among which... The number of planar blade cascade test specimens;

[0017] Will The flow region formed by extending half a grid pitch to each side from the leading and trailing edges of the blade along the grid pitch direction is defined as the blade passage, denoted as . No. 1 blade channel.

[0018] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, the first [blank] on the inlet measurement plane MP1 is defined as [blank]. grating position of each measuring point :

[0019] ;

[0020] Define the first measurement plane MP2 on the exit. grating position of each measuring point :

[0021] ;

[0022] Position of the upper grid on the inlet measuring plane MP1 and the grid position on the exit measurement plane MP2 , in Measurement points within the range, and Corresponding to the corresponding blade channel;

[0023] in,

[0024] , , For the inlet angle, outlet angle, and cascade pitch of the planar blade test specimen;

[0025] The distance from the inlet measurement plane MP1 of the planar blade cascade test specimen to the leading edge of the blade cascade;

[0026] The distance from the exit measurement plane MP2 of the planar blade cascade test specimen to the trailing edge line of the blade cascade;

[0027] for The distance from the leading edge of blade number 1 to the upper surface of the cascade plate of the planar blade test specimen;

[0028] for The distance from the trailing edge of the blade to the upper surface of the cascade plate of the planar blade test specimen;

[0029] For the first measurement plane MP1 on the import Each measuring point is located at a distance from the upper surface of the cascade plate of the planar blade cascade test specimen.

[0030] On the exit measurement plane MP2, the first Each measuring point is located at a distance from the upper surface of the cascade plate of the planar blade test piece.

[0031] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar blade cascade wind tunnel test, in step two, flow field quality inspection parameters are extracted from the outlet measurement plane MP2 at positions of 25%, 50%, 75%, and 100% within any two consecutive blade channels. Calculate the export Mach number periodic index Periodicity index of air outlet angle The periodicity of the outlet flow field is evaluated.

[0032] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, step two includes:

[0033] extract The position of the blade channel on the outlet measurement plane MP2. for , , , Exit Mach number of the measuring point , , , and extraction The position of the blade channel on the outlet measurement plane MP2. for , , , Exit Mach number of the measuring point , , , Calculate the export Mach number periodic index :

[0034] ;

[0035] Among them, Mach number reference deviation;

[0036] extract The position of the blade channel on the outlet measurement plane MP2. for , , , Air outlet angle at measuring point , , , and extraction The position of the blade channel on the outlet measurement plane MP2. for , , , Air outlet angle at measuring point , , , Calculate the periodicity index of the air angle. :

[0037] ;

[0038] in, This is the reference deviation for the airflow angle.

[0039] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality in a planar cascade wind tunnel test, step two involves evaluating the periodicity of the outlet flow field:

[0040] like and If so, the outlet flow field is considered to have good periodicity;

[0041] like and If so, the outlet flow field is considered to have good periodicity;

[0042] like or If so, it is considered that the periodicity of the outlet flow field is poor.

[0043] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, in step three, the calculation... The quality inspection parameters of the MP1 flow field at the inlet measuring plane of the blade passage are checked. average mass flow rate :

[0044] ;

[0045] in,

[0046] for The blade channel corresponds to the first... The flow field quality inspection parameters are located at each measuring point, with a total of [number] measuring points. ;

[0047] for The blade channel corresponds to the first... Density at each measuring point;

[0048] For The blade channel corresponds to the first... Axial velocity at each measuring point.

[0049] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar blade cascade wind tunnel test, in step four, the flow field quality inspection parameters of the planar MP1 flow field are measured at the inlet of any blade passage. Calculate the inlet Mach number deviation coefficient based on the average mass flow rate. Intake angle deviation coefficient The accuracy of the incoming flow is evaluated.

[0050] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, in step four, the calculation... Mach number deviation coefficient at the inlet of the blade passage :

[0051] ;

[0052] in,

[0053] for The average mass flow rate at Mach number of blade passage at inlet measurement plane MP1;

[0054] The theoretical inlet Mach number of the blade cascade is determined by the experimental conditions of the planar blade cascade.

[0055] calculate Mach number deviation coefficient at the inlet of the blade passage :

[0056] ;

[0057] for The average mass flow rate of the blade passage at the inlet measurement plane MP1 at the inlet angle;

[0058] The theoretical intake angle of the blade cascade is determined by the experimental conditions of the planar blade cascade.

[0059] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality in a planar cascade wind tunnel test, step four involves evaluating the accuracy of the incoming flow:

[0060] like and If so, the accuracy of the incoming flow is considered good;

[0061] like and If so, the accuracy of the incoming flow is relatively good;

[0062] like or If the accuracy of the incoming flow is poor, then it is considered that the accuracy of the incoming flow is poor.

[0063] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, in step five, the flow field quality inspection parameters of the planar MP1 flow field are measured at the inlet of any two consecutive blade channels. Calculate the inlet Mach number uniformity index based on the average mass flow rate. Intake angle uniformity index The uniformity of the inlet flow field is evaluated.

[0064] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality of a planar cascade wind tunnel test, step five involves calculating the inlet Mach number uniformity index. :

[0065] ;

[0066] in,

[0067] for The average mass flow rate at Mach number of blade passage at inlet measurement plane MP1;

[0068] Calculate the intake angle uniformity index :

[0069] ;

[0070] in,

[0071] for The average mass flow rate of the blade passage at the inlet measuring plane MP1 at the inlet angle.

[0072] According to at least one embodiment of this application, in the above-described method for evaluating the flow field quality in a planar cascade wind tunnel test, step five involves evaluating the uniformity of the inlet flow field:

[0073] like and If the inlet flow field is considered to be uniform, then it is considered to be good.

[0074] like and If so, the inlet flow field is considered to be relatively uniform;

[0075] like or If the uniformity of the inlet flow field is poor, it is considered that the uniformity of the inlet flow field is poor.

[0076] This application has at least the following beneficial technical effects:

[0077] This paper provides a method for evaluating the flow field quality in a planar blade cascade wind tunnel test. The method provides a comprehensive, quantitative, and standardized evaluation of the flow field quality in a planar blade cascade wind tunnel test from the aspects of incoming flow accuracy, inlet uniformity, and outlet periodicity. It can effectively overcome the shortcomings of the current method that relies on subjective judgment and has incomplete evaluation dimensions, and can significantly improve the reliability and comparability of test data. Attached Figure Description

[0078] Figure 1This application provides a schematic diagram of defining the blade channel and cascade orientation of a planar blade cascade test specimen, determining the range of the blade channel, and corresponding the inlet and outlet measuring points of the blade cascade with the blade channel.

[0079] Figure 2 This is a schematic diagram of typical measuring points at the outlet of two continuous blade channels provided in the embodiments of this application.

[0080] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0081] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0082] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0083] Precisely defining the blade passage and cascade orientation of the planar blade cascade test specimen, determining the range of the blade passage, and mapping the inlet and outlet measuring points of the cascade to the blade passage are the geometric basis for the quantitative evaluation of the flow field quality in planar blade cascade wind tunnel tests. Specifically, as follows... Figure 1 As shown.

[0084] Define the blade passages for the planar blade cascade test specimen, as detailed below:

[0085] From bottom to top, the blades of the planar blade cascade test specimen are defined sequentially as follows: blade number [number], among which... The number of planar blade cascade test specimens.

[0086] The blade has only one pressure side forming the wall of the blade channel, called the lower end wall. The blade has only one suction side forming the wall of the blade cascade channel, which is called the upper end wall.

[0087] The blade is completely within the flow field, and The flow regions formed by extending half a grid pitch to each side from the leading and trailing edges of the blade are defined as blade channels, and include a total of [missing information]. A complete blade passage, denoted as No. 1 blade channel.

[0088] Inlet angle of planar blade test specimen The exhaust angle can be determined based on the test conditions of the planar blade cascade test specimen. Grid pitch It can be determined by the design parameters of the planar blade cascade test specimen.

[0089] The distance from the inlet measuring plane MP1 of the planar blade cascade test specimen to the leading edge of the blade cascade. The distance from the exit measurement plane MP2 to the trailing edge of the blade cascade The location can be determined based on the measurement position of the test section.

[0090] The upper surface of the cascade plate of the planar blade test specimen is used as the reference.

[0091] The distance from the leading edge of blade number 1 to the upper surface of the cascade plate of the planar blade cascade test specimen is: The distance from the trailing edge point to the upper surface of the cascade plate of the planar blade test specimen is .

[0092] On the imported measuring plane MP1, the first The distance from each measuring point to the upper surface of the cascade plate of the planar blade cascade test piece is [missing information]. The first measurement plane MP2 at the exit The distance from each measuring point to the upper surface of the cascade plate of the planar blade cascade test piece is [missing information]. .

[0093] Define the first measurement plane MP1 on the inlet. grating position of each measuring point :

[0094] ………(1)

[0095] Define the first measurement plane MP2 on the exit. grating position of each measuring point :

[0096] ………(2)

[0097] Position of the upper grid on the inlet measuring plane MP1 and the grid position on the exit measurement plane MP2 , in Measurement points within the range, and Corresponding to the blade passage number. Corresponding measuring points at the exits of two consecutive blade passages, such as... Figure 2 As shown.

[0098] Based on the above, this application provides a method for evaluating the flow field quality in a planar blade cascade wind tunnel test.

[0099] Step 1: Select flow field inspection quality inspection parameters .

[0100] Based on the fundamental principles of planar blade cascade wind tunnel testing, the Mach number and airflow angle at 50% of the blade height section, which best represent the flow field characteristics of a planar blade cascade, are selected as flow field quality inspection parameters. .

[0101] Flow field quality inspection parameters This includes four airflow parameters measured on the inlet and outlet planes of the planar blade cascade test specimen, namely the inlet Mach number at 50% blade height on the inlet measurement plane MP1. Intake angle And the exit Mach number of the exit measurement plane MP2 at 50% blade height. Exhaust angle .

[0102] Step 2: Measure the flow field at the outlet of the planar blade cascade test specimen to check the quality parameters of the plane MP2. The periodicity of the outlet flow field is evaluated.

[0103] The outlet airflow parameters of the planar blade cascade test specimen are significantly affected by the blades, and the airflow parameters vary significantly along the cascade direction. On a blade channel, there is usually an alternating distribution of a clear mainstream region and a wake region. The flow in different blade channels has obvious periodicity. Therefore, it is too simplistic to evaluate the periodicity based solely on the blade channel. It is necessary to consider the consistency of airflow parameters at the corresponding cascade positions between different blade channels.

[0104] Specifically, flow field quality inspection parameters can be extracted from the outlet measurement plane MP2 at positions of 25%, 50%, 75%, and 100% within any two consecutive blade channels. Calculate the export Mach number periodic index Periodicity index of air outlet angle The periodicity of the outlet flow field is evaluated.

[0105] extract The position of the blade channel on the outlet measurement plane MP2. for , , , Exit Mach number of the measuring point , , , and extraction The position of the blade channel on the outlet measurement plane MP2. for , , , Exit Mach number of the measuring point , , , Calculate the export Mach number periodic index :

[0106] ……… (3)

[0107] Among them, The Mach number reference deviation is selected from 0.005 to 0.01 based on typical subsonic plane cascade test engineering experience and measurement uncertainty.

[0108] extract The position of the blade channel on the outlet measurement plane MP2. for , , , Air outlet angle at measuring point , , , and extraction The position of the blade channel on the outlet measurement plane MP2. for , , , Air outlet angle at measuring point , , , Calculate the periodicity index of the air angle. :

[0109] ……… (4)

[0110] in, The reference deviation for the airflow angle is selected as 0.2°~0.5° based on the engineering experience of typical subsonic plane cascade tests and measurement uncertainty.

[0111] Evaluation of the periodicity of the outlet flow field:

[0112] like and If the outlet periodicity of the two consecutive blade channels is good, then the outlet flow field is considered to be good.

[0113] like and If the outlet periodicity of the two consecutive blade channels is good, then the outlet flow field is considered to be good.

[0114] like or If this is the case, then it is assumed that the outlet periodicity of the two continuous blade channels is poor, that is, the outlet flow field is poorly periodic.

[0115] Step 3: Calculate the flow field parameters for the MP1 inlet measurement plane of the planar blade cascade test specimen to check the quality. The average mass flow rate.

[0116] Planar blade cascade tests typically focus on the average aerodynamic performance of the blade passage, which can be characterized by the mass-average airflow parameters of the blade passage.

[0117] calculate The quality inspection parameters of the MP1 flow field at the inlet measuring plane of the blade passage are checked. average mass flow rate :

[0118] …………(5)

[0119] in,

[0120] for The blade channel corresponds to the first... The flow field quality inspection parameters are located at each measuring point, with a total of [number] measuring points. ;

[0121] for The blade channel corresponds to the first... The density at each measuring point can be calculated from the static pressure, Mach number, and total temperature using aerodynamic functions and the gas state equation;

[0122] For The blade channel corresponds to the first... The axial velocity at each measuring point can be calculated from the Mach number, airflow angle, and total temperature using aerodynamic functions.

[0123] Step 4: Use the inlet of the planar blade cascade test specimen to measure the flow field in plane MP1 to check the quality inspection parameters. The average mass flow rate is used to evaluate the accuracy of the incoming flow.

[0124] Specifically, the MP1 flow field measurement parameters at the inlet plane of any blade passage can be used for quality inspection. Calculate the inlet Mach number deviation coefficient based on the average mass flow rate. Intake angle deviation coefficient The accuracy of the incoming flow is evaluated.

[0125] calculate Mach number deviation coefficient at the inlet of the blade passage :

[0126] …………(6)

[0127] in,

[0128] for The average mass flow rate at Mach number of blade passage at inlet measurement plane MP1;

[0129] The theoretical inlet Mach number of the blade cascade is determined by the experimental conditions of the planar blade cascade.

[0130] calculate Mach number deviation coefficient at the inlet of the blade passage :

[0131] …………(7)

[0132] for The average mass flow rate of the blade passage at the inlet measurement plane MP1 at the inlet angle;

[0133] The theoretical intake angle of the blade cascade is determined by the experimental conditions of the planar blade cascade.

[0134] Evaluate the accuracy of the incoming flow:

[0135] like and If the flow rate through the blade channel is good, then the accuracy of the incoming flow is considered to be good.

[0136] like and If the accuracy of the incoming flow in the blade channel is good, then it is considered that the accuracy of the incoming flow is good.

[0137] like or If the accuracy of the incoming flow in the blade channel is poor, it is considered that the accuracy is poor.

[0138] Step 5: Measure the MP1 flow field at the inlet of the planar blade cascade test specimen to check the quality inspection parameters. The average mass flow rate is used to evaluate the uniformity of the inlet flow field.

[0139] The inlet airflow parameters of a planar blade cascade are less affected by the blades, and the airflow parameters vary less along the cascade direction, typically exhibiting a flat and uniform distribution within a single blade channel. Therefore, the mass flow rate average inlet parameters can be used as a unit to examine the parameters, and a uniformity index can be defined to evaluate the inlet flow field uniformity between any two consecutive blade channels.

[0140] Specifically, the flow field and quality inspection parameters can be checked at the MP1 flow field measurement plane of any two consecutive blade channels inlet. Calculate the inlet Mach number uniformity index based on the average mass flow rate. Intake angle uniformity index The uniformity of the inlet flow field is evaluated.

[0141] Calculate the uniformity index of the imported Mach number :

[0142] …………(8)

[0143] in,

[0144] for The average mass flow rate at Mach number at the inlet measuring plane MP1 of the blade passage.

[0145] Calculate the intake angle uniformity index :

[0146] ………… (9)

[0147] in,

[0148] for The average mass flow rate of the blade passage at the inlet measuring plane MP1 at the inlet angle.

[0149] Evaluation of the uniformity of the inlet flow field:

[0150] like and If the inlet flow field of the two blade channels is considered to be of good uniformity, then it is assumed that the uniformity of the flow field is good.

[0151] like and If the inlet flow field of the two blade channels is considered to be relatively uniform, then it is assumed that the uniformity of the flow field is good.

[0152] like or If this is the case, then the inlet flow field uniformity of the two blade channels is considered to be poor.

[0153] Compared to the method of evaluating the flow field quality of a planar blade cascade wind tunnel using manual observation as described in the existing navigation standard HB 20145-2014, the flow field quality evaluation method for planar blade cascade wind tunnel tests disclosed in the above embodiments proposes quantitative flow field quality evaluation indicators and standards. On the one hand, based on key technologies and practical engineering requirements, it proposes indicators and standards for evaluating the accuracy of the incoming flow from the cascade, supplementing the deficiency of HB 20145-2014 in not paying attention to the actual incoming flow angle of attack of the cascade. This indicator can effectively improve the quality of planar blade cascade wind tunnel test data. On the other hand, based on the typical characteristics of the inlet and outlet flow fields of the planar blade cascade, it establishes evaluation indicators for the uniformity of the inlet flow field and the periodicity of the outlet flow field, making the evaluation of the flow field quality of the planar blade cascade wind tunnel more reasonable and refined, and taking into account practical engineering applicability. This makes the evaluation of the flow field quality of the planar blade cascade wind tunnel more objective and rigorous, and can improve the accuracy and efficiency of flow field quality evaluation.

[0154] The planar blade cascade wind tunnel test flow field quality evaluation method disclosed in the above embodiments provides a unified standard for establishing flow field quality. It is more comprehensive and systematic in the dimensions of planar blade cascade wind tunnel flow field quality evaluation, which can promote the continuous standardization of planar blade cascade wind tunnel test methods and provide a good technical foundation for the comparison and correlation analysis of test data between different states, different blade cascades and different wind tunnels.

[0155] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for evaluating the flow field quality in a planar blade cascade wind tunnel test, characterized in that, include: Step 1: Select flow field inspection quality inspection parameters This includes the inlet Mach number of the planar blade cascade test specimen at 50% blade height, measured on the inlet measurement plane MP1. Intake angle And the exit Mach number of the exit measurement plane MP2 at 50% blade height. Exhaust angle ; Step 2: Measure the flow field at the outlet of the planar blade cascade test specimen to check the quality parameters of the plane MP2. To evaluate the periodicity of the outlet flow field; Step 3: Calculate the flow field parameters for the MP1 inlet measurement plane of the planar blade cascade test specimen to check the quality. The average mass flow rate; Step 4: Use the inlet of the planar blade cascade test specimen to measure the flow field in plane MP1 to check the quality inspection parameters. The average mass flow rate is used to evaluate the accuracy of the incoming flow. Step 5: Measure the MP1 flow field at the inlet of the planar blade cascade test specimen to check the quality inspection parameters. The average mass flow rate is used to evaluate the uniformity of the inlet flow field.

2. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 1, characterized in that, in, Define the blade passage of the planar blade cascade test specimen: From bottom to top, the blades of the planar blade cascade test specimen are defined sequentially as follows: blade number [number], among which... The number of planar blade cascade test specimens; Will The flow region formed by extending half a grid pitch to each side from the leading and trailing edges of the blade along the grid pitch direction is defined as the blade passage, denoted as . No. 1 blade channel.

3. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 2, characterized in that, in, Define the first measurement plane MP1 on the inlet. grating position of each measuring point : ； Define the first measurement plane MP2 on the exit. grating position of each measuring point : ； Position of the upper grid on the inlet measuring plane MP1 and the grid position on the exit measurement plane MP2 , in Measurement points within the range, and Corresponding to the corresponding blade channel; in, , , For the inlet angle, outlet angle, and cascade pitch of the planar blade test specimen; The distance from the inlet measurement plane MP1 of the planar blade cascade test specimen to the leading edge of the blade cascade; The distance from the exit measurement plane MP2 of the planar blade cascade test specimen to the trailing edge line of the blade cascade; for The distance from the leading edge of blade number 1 to the upper surface of the cascade plate of the planar blade test specimen; for The distance from the trailing edge of the blade to the upper surface of the cascade plate of the planar blade test specimen; For the first measurement plane MP1 on the import Each measuring point is located at a distance from the upper surface of the cascade plate of the planar blade cascade test specimen. On the exit measurement plane MP2, the first Each measuring point is located at a distance from the upper surface of the cascade plate of the planar blade test piece.

4. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 3, characterized in that, In step two, the flow field quality inspection parameters of the outlet measurement plane MP2 at positions of 25%, 50%, 75%, and 100% within any two consecutive blade channels are extracted. Calculate the export Mach number periodic index Periodicity index of air outlet angle The periodicity of the outlet flow field is evaluated.

5. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 4, characterized in that, In step two: extract The position of the blade channel on the outlet measurement plane MP2. for , , , Exit Mach number of the measuring point , , , and extraction The position of the blade channel on the outlet measurement plane MP2. for , , , Exit Mach number of the measuring point , , , Calculate the export Mach number periodic index : ； Among them, Mach number reference deviation; extract The position of the blade channel on the outlet measurement plane MP2. for , , , Air outlet angle at measuring point , , , and extraction The position of the blade channel on the outlet measurement plane MP2. for , , , Air outlet angle at measuring point , , , Calculate the periodicity index of the air angle. : ； in, This is the reference deviation for the airflow angle.

6. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 5, characterized in that, In step two, the periodicity of the outlet flow field is evaluated: like and If so, the outlet flow field is considered to have good periodicity; like and If so, the outlet flow field is considered to have good periodicity; like or If so, it is considered that the periodicity of the outlet flow field is poor.

7. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 6, characterized in that, In step three, calculate The quality inspection parameters of the MP1 flow field at the inlet measuring plane of the blade passage are checked. average mass flow rate : ； in, for The blade channel corresponds to the first... The flow field quality inspection parameters are located at each measuring point, with a total of [number] measuring points. ; for The blade channel corresponds to the first... Density at each measuring point; For The blade channel corresponds to the first... Axial velocity at each measuring point.

8. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 7, characterized in that, In step four, the quality inspection parameters are checked using the MP1 flow field measurement plane at the inlet of any blade passage. Calculate the inlet Mach number deviation coefficient based on the average mass flow rate. Intake angle deviation coefficient The accuracy of the incoming flow is evaluated.

9. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 8, characterized in that, In step four, calculate Mach number deviation coefficient at the inlet of the blade passage : ； in, for The average mass flow rate at Mach number of blade passage at inlet measurement plane MP1; The theoretical inlet Mach number of the blade cascade is determined by the experimental conditions of the planar blade cascade. calculate Mach number deviation coefficient at the inlet of the blade passage : ； for The average mass flow rate of the blade passage at the inlet measurement plane MP1 at the inlet angle; The theoretical intake angle of the blade cascade is determined by the experimental conditions of the planar blade cascade.

10. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 9, characterized in that, In step four, the accuracy of the incoming flow is evaluated: like and If so, the accuracy of the incoming flow is considered good; like and If so, the accuracy of the incoming flow is relatively good; like or If the accuracy of the incoming flow is poor, then it is considered that the accuracy of the incoming flow is poor.

11. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 10, characterized in that, In step five, the quality inspection parameters are checked using the flow field measurement plane MP1 at the inlet of any two consecutive blade channels. Calculate the inlet Mach number uniformity index based on the average mass flow rate. Intake angle uniformity index The uniformity of the inlet flow field is evaluated.

12. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 11, characterized in that, In step five, the uniformity index of the inlet Mach number is calculated. : ； in, for The average mass flow rate at Mach number of blade passage at inlet measurement plane MP1; Calculate the intake angle uniformity index : ； in, for The average mass flow rate of the blade passage at the inlet measuring plane MP1 at the inlet angle.

13. The method for evaluating the flow field quality in a planar blade cascade wind tunnel test according to claim 12, characterized in that, In step five, the uniformity of the inlet flow field is evaluated: like and If the inlet flow field is considered to be uniform, then it is considered to be good. like and If so, the inlet flow field is considered to be relatively uniform; like or If the uniformity of the inlet flow field is poor, it is considered that the uniformity of the inlet flow field is poor.

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