Recently, the research team of the key laboratory of the Ministry of Education of Aerospace Micro-nano System of Northwestern Polytechnical University developed the world's first set of fluid wall surface shear stress tester.
In 2013, the “Development and Application of Fluid Wall Shear Stress Tester”, a project of national major science instrument equipment led by the Northwestern Polytechnical University and organized by the Ministry of Industry and Information Technology, was formally established. This project is based on national major projects such as aerospace vehicles and new types of ships. The research and development of experimental fluid mechanics instruments is a goal. It plans to develop a fluid wall surface shear stress tester with independent intellectual property rights, sound functions, and stable and reliable quality. By 2020, it will achieve an annual production capacity of 150 complete machines with a research funding of 65.58 million. yuan.
The fluid wall surface shear stress is one of the most basic fluid mechanics parameters. It is a direct physical quantity to study the boundary layer flow state. It is the most important basis for the fine control and control of frictional resistance. However, because the shear stress value is extremely small, the dynamic property is high. The flow field is easily subject to interference and destruction, and there has been no effective test means or specialized instrumentation at home and abroad, which has affected the development of related science and technology industries and major engineering construction.
Northwestern Polytechnical University held several meetings in several years, promoting the development and application of the fluid wall surface shear stress tester, and finally successfully developed the world's first set of fluid wall surface shear stress tester. The tester makes full use of the microelectromechanical system ( MEMS technology is highly integrated, with high sensitivity and good dynamics. Through the establishment of micro-machining technology and testing specifications, two key types of core devices, flexible thermal-sensitive thin-film micro-sensors and floating shear-stress micro-sensors, have been developed. The probe can capture the flow field data at different positions and analyze the flow state. The complete set of wall shear stress measurement instruments has a measuring range of 0-60Pa, a resolution of 0.3Pa, an accuracy of 5%, and has the advantage of small disturbance to the flow field.
In addition, Northwestern Polytechnical University has cooperated with China COMAC Shanghai Aircraft Design & Research Institute and other institutions to confirm the instrument's high-performance miniature sensitive probe technology, weak signal anti-interference measurement system technology and complex and harsh working environment probes. The package protection technology provides effective test data support for large passenger aircraft, aero engines, underwater vehicle shape design and estuary coast engineering. And the instrument has reached the national standard GB/T6587-2012 (general specification of electronic measuring instruments) requirements.
At present, the team has completed the micro-sensor probe, instrument machine engineering manufacturing and testing platform, built the precision machining, assembly and other processes and reliability quality assurance system required for instrument production.
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