A method for real-time monitoring and offline correction of wind tunnel pressure test data

Abstract

This invention discloses a method for real-time monitoring and offline correction of wind tunnel pressure test data. The aim is to solve a series of problems encountered during pressure testing, such as the inability to monitor the operating status of the pressure acquisition system, the inability to compare unknown data values, and the difficulty in determining the quality of test data. Without adding peripheral equipment, this invention fully utilizes the potential of existing pressure acquisition system equipment to achieve real-time dynamic monitoring of pressure data and provides a basis for offline data analysis and correction. Through analogy comparison, real-time monitoring of the operating status of the pressure acquisition system is achieved, reducing the risks of test run scrapping and data invalidation due to equipment failure. This invention requires minimal system modifications, is flexible and convenient to operate, and is economical and practical. The difference between the synchronously acquired set constant pressure and the measured constant pressure provides a basis for subsequent offline correction of the test data, improving data accuracy.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic wind tunnel testing technology, specifically to a method for real-time monitoring and offline correction of wind tunnel pressure test data. Background Technology

[0002] Pressure distribution tests on aircraft model surfaces (i.e., pressure measurement tests) are a common wind tunnel test conducted during aircraft development. This test typically involves machining pressure measurement holes at specific locations on the model surface, connecting them to an air intake pipe via a pressure acquisition system to obtain pressure data. This data reveals the pressure distribution on the surfaces of various aircraft components. The test data provides raw data on aerodynamic load distribution for calculating the structural strength of the aircraft and its components, and also provides experimental evidence for studying the performance and flow characteristics of the aircraft and its components. Therefore, the accuracy of the measurement data directly affects the correct evaluation of the overall performance of the aircraft, and consequently, the success or failure of the development work. However, as a dynamic experimental process, the pressure measurement test data is closely related to factors such as aircraft configuration, flow field conditions, and model attitude. Its theoretical true value is unknown. Therefore, correctly determining the quality of the acquired raw test data and avoiding economic losses due to the scrapping of test vehicles becomes a problem that relevant researchers must address.

[0003] Currently, most transonic wind tunnels, both domestically and internationally, utilize electronic scanning valve systems for pressure acquisition. These systems typically consist of a control unit, a pressure scanning module, a pressure calibration unit, a high-precision power supply, and an interface module. The core of the system, the pressure scanning module, is a miniature electronic differential pressure measurement unit comprised of multiple silicon piezoresistive pressure sensors. Before the experiment, several standard pressures are set in the pressure calibration unit, and the system's air path switching function is used to apply these standard pressures to the sensor measurement interfaces, enabling real-time on-site calibration of the pressure scanning module and improving measurement accuracy in the field environment. During the experiment, the sensor measurement interfaces are switched to connect to pressure measurement holes on the model surface to complete the acquisition of raw experimental data. Summary of the Invention

[0004] The purpose of this invention is to solve a series of problems during pressure testing, such as the inability to monitor the operation of the pressure acquisition system, the inability to compare the true value of the data due to unknown data, and the difficulty in judging the quality of the test data. This invention proposes a method for real-time monitoring and offline correction of wind tunnel pressure test data. Without adding system peripherals, it fully explores the potential of existing pressure acquisition system equipment, realizes real-time dynamic monitoring of pressure data, and provides a basis for offline analysis and correction of the data.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for real-time monitoring and offline correction of wind tunnel pressure test data includes the following steps:

[0007] Step 1: During the pressure test preparation process, while ensuring the electrical wiring required by the pressure acquisition system is met, an additional pressure monitoring pipeline is installed.

[0008] Step 2: Select one or more pressure measurement points on each pressure scanning module, connect the pipelines of the selected pressure measurement points with a multi-way connector, and connect them to one end of the added pressure monitoring pipeline. Lead the other end of the added pressure monitoring pipeline to the location of the pressure calibration unit.

[0009] Step 3: Following the standard test preparation procedure, complete the connection of all electrical circuits of the pressure acquisition system, and connect the pressure measurement points on the pressure scanning module (excluding the selected pressure measurement points) to the air ducts of the pressure measurement holes on the model surface.

[0010] Step 4: Before conducting the test, after the pressure acquisition system has completed the online calibration of the pressure scanning module, disconnect the pipeline connected to the calibration pressure output terminal of the pressure calibration unit at the gas path end where the pressure calibration unit is located, and connect the calibration pressure output terminal to the pressure monitoring pipeline.

[0011] Step 5: Before conducting the test, set a constant pressure value on the pressure calibration unit and output it from the calibration pressure output port;

[0012] Step Six: Before conducting the test, start the pressure acquisition system to begin data acquisition, observe the measured value of the pressure measurement point connected to the pressure monitoring pipeline selected on the pressure scanning module, and start the wind tunnel and begin the test when the difference between the measured value and the constant pressure value set in Step Five is within the data accuracy tolerance range.

[0013] Step 7: During the test, observe the changes in the differential pressure value from Step 6 in real time. Based on the changes in the differential pressure value, make a prediction on the operating status of the pressure acquisition system and the quality of the test data, and determine whether to terminate the test.

[0014] Step 8: After the test, check the changes in the differential pressure value from Step 6 throughout the entire test. Where the differential pressure value exceeds the tolerance range, use the actual measured value of the pressure monitored at the same time to correct the collected raw test data. The correction is as follows:

[0015] ,in: The pressure measurement value at the monitoring point selected by the i-th pressure scanning module. The constant pressure value set on the pressure calibration unit, The corrected pressure measurement value at the j-th pressure measurement point of the i-th pressure scanning module. This is the pressure measurement value at the j-th pressure measurement point of the i-th pressure scanning module before correction.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] By using the analogy comparison method, real-time monitoring of the operating status of the pressure acquisition system was achieved, reducing the risks of test vehicle scrapping and data failure that may result from equipment failure.

[0018] By making full use of the existing equipment in the pressure acquisition system, accurate pressure monitoring settings are achieved without adding external devices. The system requires minimal modification, is flexible and convenient to operate, and is economical and practical.

[0019] The difference between the set constant pressure and the measured constant pressure, collected synchronously, provides a basis for the subsequent offline correction of the experimental data, thus improving the accuracy of the data. Attached Figure Description

[0020] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0021] Figure 1 This is a diagram of the system connections. Detailed Implementation

[0022] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0023] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0024] like Figure 1 The system configuration of this embodiment is as follows: the pressure acquisition system uses the PSI8400 system, which mainly consists of a control host, a system processor (SP) (including a fiber optic interface unit (FIU) inserted into the SP and a 30psia pressure calibration unit (PCU)), a scan digital interface (SDI), an 8491 remote power supply device, and two ±15psid ESP-64HD DTC pressure measurement modules.

[0025] During test preparation, conventional system circuit cables were laid, along with five control air lines (C1, C2, C / REF, R / REF, and CAL). In addition, a pressure monitoring line P was added.

[0026] Select 64 points on each of the two pressure testing modules, and connect these two points to the two ports of the tee connector. Connect the third port of the tee connector to one end of pipe P. Lead the other end of pipe P to the location of SP.

[0027] Following standard test preparation procedures, complete all electrical connections for the PSI8400 system, and connect the pressure testing port air vent lines to all pressure testing modules except for point 64. Specifically, one end of the C1 and C2 lines is connected via a tee connector to the C1 and C2 interfaces of the two pressure testing modules respectively, and the other end is connected to the C1 and C2 interfaces of the SP respectively; one end of the C / REF and R / REF lines is connected via a tee connector to the C / REF and R / REF interfaces of the two pressure testing modules respectively, and the other end is placed at the REF position of the SP, open to the atmosphere; one end of the CAL line is connected via a tee connector to the CAL interface of the two pressure testing modules, and the other end is connected to the CAL4 interface of the PCU.

[0028] Before the test, use the CV1 command to push the valve body of the pressure measuring module to the calibration end, and complete the on-site calibration and inspection of all pressure measuring modules as usual.

[0029] After completing the above calibration checks, disconnect the CAL line connected to the PCU's CAL 4 interface, and connect one end of line P at the location of SP to the PCU's CAL 4 interface. Then, using the CV1 command, push the pressure measurement module valve body to the measuring end, and using the PC2 command, set the PCU calibration pressure to 30 kPa, outputting it from the PCU's CAL 4 interface.

[0030] Before the test, the 8400 system was started to collect data and observe the measured values ​​at 64 points on the two pressure measurement modules. When the measured values ​​gradually stabilized and remained within the range of 30 kPa ± 0.030 kPa, the wind tunnel was started and the test began.

[0031] During the test, the changes in the measured values ​​at 64 points on the two pressure measuring modules were monitored in real time. If the value fluctuated within the range of 30kPa±0.030kPa, it indicated that the 8400 system was operating normally and the data was reliable. If the value fluctuated beyond the range of 30kPa±0.030kPa, it indicated that there might be a problem, and the test could be terminated if necessary.

[0032] After the test, the changes in the 64 measured values ​​on the two pressure measuring modules were checked throughout the test. For the data segment whose value exceeded the range of 30kPa±0.030kPa, the collected data was corrected using the following formula:

[0033] ,in: The pressure measurement value at the monitoring point selected by the i-th pressure scanning module. The constant pressure value set on the pressure calibration unit, The corrected pressure measurement value at the j-th pressure measurement point of the i-th pressure scanning module. This is the pressure measurement value at the j-th pressure measurement point of the i-th pressure scanning module before correction.

[0034] For example: If the inspection reveals that the pressure values ​​at 64 points from time t to t+2 are 30.042, 30.036, and 29.045 kPa respectively, all exceeding the tolerance range of 30 ± 0.030 kPa, then the data collected from other pressure measurement points of this module need to be corrected. The correction formulas are as follows:

[0035] At time t: Pjt_repair = Pjt_measure - (30.042 - 30), j = 1~63;

[0036] At time t+1: Pjt_repair = Pjt_measure - (30.036 - 30), j = 1~63;

[0037] At time t+2: Pjt_repair = Pjt_measure - (29.045 - 30), j = 1~63.

[0038] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for real-time monitoring and offline correction of wind tunnel pressure test data, characterized in that... Includes the following steps: Step 1: During the pressure test preparation process, while ensuring the electrical wiring required by the pressure acquisition system is met, an additional pressure monitoring pipeline is installed. Step 2: Select any pressure measurement point on each pressure scanning module, connect the pipeline of the selected pressure measurement point with a multi-way connector, and then connect it to one end of the added pressure monitoring pipeline. Lead the other end of the added pressure monitoring pipeline to the location of the pressure calibration unit. Step 3: Following the standard test preparation procedure, complete the connection of all electrical circuits of the pressure acquisition system, and connect the pressure measurement points on the pressure scanning module, except for the selected measurement points, to the air vent pipes of the pressure measurement holes; Step 4: Before conducting the test, after the pressure acquisition system has completed the online calibration of the pressure scanning module, disconnect the pipeline connected to the calibration pressure output terminal of the pressure calibration unit at the gas path end where the pressure calibration unit is located, and connect the calibration pressure output terminal to the pressure monitoring pipeline. Step 5: Before conducting the test, set a constant pressure value on the pressure calibration unit and output it from the calibration pressure output port; Step Six: Before conducting the test, start the pressure acquisition system to begin data acquisition, observe the measured value of the pressure measurement point connected to the pressure monitoring pipeline selected on the pressure scanning module, and start the wind tunnel and begin the test when the difference between the measured value and the constant pressure value set in Step Five is within the data accuracy tolerance range. Step 7: During the test, observe the changes in the differential pressure value from Step 6 in real time. Based on the changes in the differential pressure value, make a prediction on the operating status of the pressure acquisition system and the quality of the test data, and determine whether to terminate the test. Step 8: After the test, check the changes in the differential pressure value from Step 6 throughout the entire test. Where the differential pressure value exceeds the tolerance range, use the actual measured value of the pressure monitored at the same time to correct the collected original test data. The correction is as follows: ,in: The pressure measurement value at the monitoring point selected by the i-th pressure scanning module. The constant pressure value set on the pressure calibration unit, The corrected pressure measurement value at the j-th pressure measurement point of the i-th pressure scanning module. This is the pressure measurement value at the j-th pressure measurement point of the i-th pressure scanning module before correction.

2. The method for real-time monitoring and offline correction of wind tunnel pressure test data according to claim 1, characterized in that... In step two, one or more pressure measurement points are selected on the pressure scanning module.

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