Study On Flowrate Measurement Method In Micro-scale Based On Fluidic Oscillation Principle

Abstract: The flow measuremet is one of the important parameters monitoredof industrial manufacture and scientific research. In recent years, the minia-turization, integration and intelligentization of devices have become an in-ternational hot research topic, especially the development of the Micro Elec-tromechanical System (MEMS) technology which poses a new challenge tomeasure flow accurately under a small scale. The development of fluid flowmeasurement technology restricts the improvement of miniaturization andperformance of microfluidic devices, so the emergence and application of themicrofluidic flow sensors are desperately needed. In view of the problemsmentioned above, the small scale jet oscillator is studied in aspects of theoryanalysis, structure design，simulation and Micro-PIV test. In detail, the majorcontributions of this thesis are as follow:(1) In view of the problems of low flow rate in MEMS, the advantageand deficiency of all kind of miniature flow sensors as well as present re-search situation based on MEMS in industrial field is analyzed. Combinedtogether with current research situation, a flowrate measurement methodbased on jet oscillation is proposed.(2) The working principle and the measurement method of the jet oscil-lator were described. According to the basic character of jet flow and bista-bility structure, the principle of entrainment effect, wall attachment and jetoscillation were discussed.(3) Two small-scale jet oscillators are designed based on bistabilitystructure. One is the symmetric feedback channel with non-splitting jet os-cillator, the other is non-feedback channel with ω-shaped block jet oscillator.The two small-scale jet oscillators are produced by wet etching technology.(4) Simulation tests on the two small-scale jet oscillators are conducted.Measurement models of the two small-scale jet oscillators are established byanalyzing the dynamic features of the oscillating chamber. The relationship between Reynolds number and Strouhsl Number and the minimum vibrationspeed of the two small-scale jet oscillators are also studied.(5) The Micro-PIV test was conducted on the non-feedback channel os-cillator proposed, preliminary experiment results shows that the non-feedbackchannel oscillator can induce fluidic oscillating.