CN114964701A - Model surface pressure continuous measurement test system based on pressure scanning valve - Google Patents

Abstract

The invention discloses a model surface pressure continuous measurement test system based on a pressure scanning valve, which comprises a pressure acquisition system and an angle acquisition system of a model surface and a main control machine, wherein the pressure acquisition system mainly comprises two sets of pressure scanning valves and a system processor, the angle acquisition system comprises VXI data acquisition equipment, the main control machine triggers the two sets of acquisition systems through a trigger mode and starts to acquire according to respective sampling rates, when the value of an angle channel signal enters a corresponding value of a test angle, the time from the moment corresponding to the corresponding angle to the moment when the sampling is started is recorded, meanwhile, the measured value of the scanning valve at the corresponding moment is found and stored, and the acquired measured parameters are selected and processed to obtain measured parameters under an attitude angle. In the process that the attitude angle of the model changes at a constant speed, the method can acquire sufficiently dense aerodynamic characteristic data, and improves the efficiency of the wind tunnel pressure measurement test.

Description

Model surface pressure continuous measurement test system based on pressure scanning valve

Technical Field

The invention belongs to the technical field of aerodynamic wind tunnel tests, and particularly relates to a model surface pressure continuous measurement test system based on a pressure scanning valve.

Background

The wind tunnel experiment technology is widely used as a method for aerodynamic research, and provides necessary guarantee for the development of the fields of aviation, aerospace and the like. The conventional wind tunnel pressure measurement test is a test angle sequence which is proposed by a customer unit in advance and is measured one by one according to the angles in the test. In the test, after the model is in place and stable, each angle needs to acquire test data of the position, and each required angle needs to perform the step until the train number is finished. The method is very good in data acquisition stability, and can truly reflect the model state at the current angle. However, this method also has certain disadvantages, such as a small amount of test data, incomplete information on the aerodynamic characteristics of the aircraft, and the like.

The existing model surface pressure measurement and force measurement test process comprises the following steps: after the wind speed is stable, when the model moves to an angle, the pressure acquisition system and the angle acquisition system on the surface of the model start to acquire in parallel according to respective sampling frequency of equipment, two data files are formed after the test is finished and are provided for data analysts, no matter the synchronism of the system acquisition or the time synchronism of the corresponding data of each point can not be guaranteed, and the test data volume provided by one wind is limited, and only the pressure measurement data and the force measurement data corresponding to the angle sequence in the test plan list are obtained.

Disclosure of Invention

Based on the defects, the invention provides the model surface pressure continuous measurement test system based on the pressure scanning valve, and solves the problems of low efficiency and small information quantity of test results of conventional stepping attitude angle static tests in low-speed wind tunnels in the prior art.

The technical scheme adopted by the invention is as follows: a model surface pressure continuous measurement test system based on a pressure scanning valve comprises a pressure acquisition system, an angle acquisition system and a main control computer, wherein the pressure acquisition system comprises two sets of PSI8400 pressure scanning valves, a system processor, an optical fiber interface unit, a scanning valve digital interface unit, a scanning valve interface unit and a plurality of sets of pressure calibration units; the main control computer triggers two sets of acquisition systems through a triggering mode and starts to acquire according to respective sampling rates, the VXI data acquisition system detects the signal change of an angle acquisition channel in real time, when the value of an angle channel signal enters a corresponding value of a test angle, the time of the moment of the corresponding angle from the moment of starting sampling is recorded, the measured value of a PSI8400 pressure scanning valve at the corresponding moment is found according to the time and stored, the pressure acquisition of all test angles is circulated until the pressure acquisition of all test angles is completed, the acquired data is selected and processed according to a specific rule, and therefore the measured parameters under the required attitude angle are obtained.

It is another object of the present invention to provide a test method using the test system as described above, as follows: after the test wind speed is stable, the angle mechanism starts to operate at a constant speed within a set angle range, the acquisition frequency of the VXI data acquisition system is 125Hz, the point measuring frequency of the PSI8400 pressure scanning valve is 20Hz, the two systems are triggered by a triggering mode to start acquisition according to respective sampling rates, the VXI data acquisition system detects the signal change of an angle acquisition channel in real time, when the value of the angle channel signal enters a corresponding value of the test angle, the VXI data acquisition system records the force measurement data of a balance corresponding to the current angle channel and also records the time from the moment corresponding to the angle to the moment of starting sampling, the pressure measurement acquisition unit finds the pressure measurement value at the moment corresponding to the test angle according to the time, analyzes, displays and stores the pressure measurement value, ensures that the data acquired by the two acquisition systems are completely the data at the same angle and the same moment, and circulates until the data acquisition of all the test angles is completed, the train number test is completed.

Further, after the test wind speed is stable, the angle mechanism starts to run at a constant speed within a set angle range of-4-20 degrees, and the surface pressure data of the model is acquired: the sampling period is 50ms, 20 points are collected every second, and 2112 points are collected in the total test time; the total time is 105.6s, and a 2112 x n data matrix is obtained; collecting model angle data: the sampling period is 8ms, 125 points are collected every second, the angular rate of model angular travel is 0.25 degrees/S, the angular range is minus 4 degrees to 20 degrees, the interval is 0.5 degrees, then a sampling point sequence under the corresponding angular point is obtained, and finally a data matrix of 49 multiplied by 2 angles and sampling points is obtained; time series: obtaining a time sequence, namely sampling points corresponding to a specific angle, through a formula 1; then obtaining the number of rows of the model pressure data matrix matched with the specific angle point according to the sampling frequency difference between the PSI8400 pressure scanning valve and the VXI data acquisition equipment by a formula 2,

and finally, matching the number of lines required to be found in the corresponding rows of the model pressure data matrix according to the corresponding points, and extracting data to obtain a 49 x (n +1) model pressure data matrix within an angle range of-4-20 degrees.

The invention has the advantages and beneficial effects that: the invention can realize the continuous collection of pressure data in the motion process of the model, so that pressure data under a series of mechanism angle changes can be obtained in one experiment; in the process that the attitude angle of the model changes at a constant speed, the pneumatic characteristic data which are dense enough can be collected, the pressure measurement test efficiency of the wind tunnel is greatly improved, more complete and rich pneumatic data are provided, the blowing time is reduced, and the test cost is reduced. This is more conducive to a complete and accurate understanding of the aerodynamic characteristics of the aircraft.

Drawings

Fig. 1 is a schematic diagram of a load cell of the present invention.

FIG. 2 is a data processing flow diagram of the present invention.

Detailed Description

The invention is further described below with reference to the examples of the drawings.

Example 1

The utility model provides a model surface pressure continuous measurement test system based on pressure scanning valve, includes pressure acquisition system and angle acquisition system and the main control computer on model surface, as shown in figure 1, pressure acquisition system include two sets of PSI8400 pressure scanning valve 6, system processor 2, optical fiber interface unit 3, the digital interface unit 4 of scanning valve, scanning valve interface unit 5 and three sets of pressure calibration unit 7, main control computer 1 and system processor 2 pass through the ethernet communication, system processor 2 respectively with optical fiber interface unit 3, three sets of pressure calibration unit 7 electric signal connection, optical fiber interface unit 3 and the digital interface unit 4 optical fiber communication of scanning valve, the digital interface unit 4 of scanning valve is connected with two sets of PSI8400 pressure scanning valve 6 through scanning valve interface unit 5. The angle acquisition system comprises VXI data acquisition equipment, and the VXI data acquisition equipment is connected with the main control computer through an electric signal.

The main control machine triggers two sets of systems through a triggering mode and starts to collect according to respective sampling rates, the VXI data collecting system detects signal changes of the angle collecting channels in real time, when the value of the angle channel signal enters a corresponding value of a test angle, the time of the corresponding angle at the moment from the sampling starting moment is recorded, the measured value of the test system is continuously measured according to the model surface pressure at the corresponding moment and stored, and the process is circulated until the pressure collection of all the test angles is completed.

In the embodiment, in the range of the attitude angle required to be measured, the measured parameters are collected according to the continuous change of the model attitude angle, and then the collected mass data are selected and processed according to a specific rule, so that the measured parameters under the required attitude angle are obtained. Namely, the pressure measurement value at the moment corresponding to the test angle is found by utilizing the continuous acquisition function of the VXI data acquisition system and the PSI8400 pressure scanning valve, and the pressure measurement value is analyzed, displayed, stored and processed, so that the pressure measurement test is completed.

Example 2

The test method using the system of example 1 was as follows: as shown in fig. 2, when the test angle is-4 to 20 degrees, after the test wind speed is stable, the angle mechanism starts to run at a constant speed to 20 degrees from-4 degrees, the acquisition frequency of the VXI data acquisition system is 125Hz, the measurement point frequency of the PSI8400 pressure scanning valve is 20Hz, the two sets of systems are triggered by a trigger mode to start acquisition according to respective sampling rates, the VXI data acquisition system detects the signal change of the angle acquisition channel in real time, when the value of the angle channel signal enters the corresponding value of the test angle, the VXI data acquisition system records the force measurement data of the balance corresponding to the current angle channel, and simultaneously records the time from the moment corresponding to the current angle channel to the moment when the sampling is started, and the pressure measurement acquisition unit finds the pressure measurement value at the moment corresponding to the test angle according to the time, analyzes, displays and stores the pressure measurement value, thereby ensuring that the data acquired by the two sets of acquisition systems are completely the same angle, And circulating the data at the same moment until the data acquisition of all test angles is completed, namely completing the train number test.

Wherein, the model pressure data acquisition: sampling period is 50ms, 20 points are collected every second, and 2112 points are collected in the total test time; the total time is 105.6s, and a 2112 x n data matrix is obtained;

collecting model angle data: sampling period is 8ms, 125 points are collected every second, the angular rate of model angle travel is 0.25 DEG/S, the angular range is-4-20 DEG, the interval is 0.5 DEG, further, a sampling point sequence under the corresponding angular point is obtained, and finally, a data matrix of 49 multiplied by 2 angles and sampling points is obtained;

time series: obtaining a time sequence, namely sampling points corresponding to a specific angle, through a formula 1; then obtaining the number of rows of the model pressure data matrix matched with the specific angle point according to the sampling frequency difference between the PSI8400 pressure scanning valve and the VXI data acquisition equipment by a formula 2,

and finally, matching the number of lines required to be found in the corresponding rows of the model pressure data matrix according to the corresponding points, and extracting data to obtain a 49 x (n +1) model pressure data matrix within an angle range of-4-20 degrees.

The PSI8400 pressure scanning valve adopted in the embodiment is a modularized parallel processing pressure acquisition system, and at most 64 high-speed 8-bit microprocessors are combined and integrated into one 32-bit microprocessor in an input component meeting a specified measurement task, so that very high acquisition and throughput measurement speed can be provided, and a hardware guarantee is provided for a continuous measurement technology for realizing pressure data.

Claims (3)

1. The utility model provides a model surface pressure continuous measurement test system based on pressure scanning valve, includes the pressure acquisition system and the angle acquisition system and the main control computer on model surface, its characterized in that: the pressure acquisition system comprises two sets of PSI8400 pressure scanning valves, a system processor, an optical fiber interface unit, a scanning valve digital interface unit, a scanning valve interface unit and a plurality of sets of pressure calibration units, a main control computer is communicated with the system processor through an Ethernet, the system processor is respectively in electric signal connection with the optical fiber interface unit and the plurality of sets of pressure calibration units, the optical fiber interface unit is in optical fiber communication with the scanning valve digital interface unit, the scanning valve digital interface unit is connected with the two sets of PSI8400 pressure scanning valves through the scanning valve interface unit, the angle acquisition system comprises VXI data acquisition equipment, and the VXI data acquisition equipment is in electric signal connection with the main control computer; the main control computer triggers two sets of acquisition systems through a triggering mode and starts to acquire according to respective sampling rates, the VXI data acquisition system detects the signal change of an angle acquisition channel in real time, when the value of an angle channel signal enters a corresponding value of a test angle, the time of the moment of the corresponding angle from the moment of starting sampling is recorded, the measured value of a PSI8400 pressure scanning valve at the corresponding moment is found according to the time and stored, the pressure acquisition of all test angles is circulated until the pressure acquisition of all test angles is completed, the acquired data is selected and processed according to a specific rule, and therefore the measured parameters under the required attitude angle are obtained.

2. A test method obtained by a model surface pressure continuous measurement test system based on a pressure scanning valve according to claim 1, characterized in that the method comprises the following steps: after the test wind speed is stable, the angle mechanism starts to operate at a constant speed within a set angle range, the acquisition frequency of the VXI data acquisition system is 125Hz, the point measuring frequency of the PSI8400 pressure scanning valve is 20Hz, the two systems are triggered by a triggering mode to start acquisition according to respective sampling rates, the VXI data acquisition system detects the signal change of an angle acquisition channel in real time, when the value of the angle channel signal enters a corresponding value of the test angle, the VXI data acquisition system records the force measurement data of a balance corresponding to the current angle channel and also records the time from the moment corresponding to the angle to the moment of starting sampling, the pressure measurement acquisition unit finds the pressure measurement value at the moment corresponding to the test angle according to the time, analyzes, displays and stores the pressure measurement value, ensures that the data acquired by the two acquisition systems are completely the data at the same angle and the same moment, and circulates until the data acquisition of all the test angles is completed, the train number test is completed.

3. A test method according to claim 2, characterized in that the method is as follows: after the test wind speed is stable, the angle mechanism starts to run at a constant speed within-4-20 degrees in a set angle range,

collecting model surface pressure data: sampling period is 50ms, 20 points are collected every second, and 2112 points are collected in the total test time; the total time is 105.6s, and a 2112 x n data matrix is obtained;

collecting model angle data: sampling period is 8ms, 125 points are collected every second, the angular rate of model angle travel is 0.25 DEG/S, the angular range is-4-20 DEG, the interval is 0.5 DEG, further, a sampling point sequence under the corresponding angular point is obtained, and finally, a data matrix of 49 multiplied by 2 angles and sampling points is obtained;

time series: obtaining a time sequence, namely sampling points corresponding to specific angles, through a formula 1; then obtaining the number of lines of a model pressure data matrix matched with a specific angle point according to the sampling frequency difference of the PSI8400 pressure scanning valve and the VXI data acquisition equipment by a formula 2,

and finally, matching the number of lines required to be found in the corresponding rows of the model pressure data matrix according to the corresponding points, and extracting data to obtain a 49 x (n +1) model pressure data matrix within an angle range of-4-20 degrees.

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