| Summary: | 碩士 === 國立聯合大學 === 機械工程學系碩士班 === 105 === This study explored the flow on a flat-plate triboelectric electrode with leading step inside Kármán vortex street, and application Eddy current flowmeter. When the Reynolds number of eddy current dissipation frequency behind the cylinder is less than , Strouhal Numberm value is about 0.2, the vortex oscillation frequency will be proportional to the wind speed.
In this study, the flow field was measured by wind tunnel experiment, and the finite element method (FEM) was used to simulate the two-dimensional flow field. A commercially available multiphysics simulation was used for FEM analysis. Analysis of the parameters for the pipe height to diameter ratio is 8.33, Reynolds number is 4000, the eletrode distance from the cylinder is 12mm and 18mm. Use the Hot wire Anemometer (HWA) to measure the oscillation frequency. The frequency are 300 Hz, 335 HZ when the electrode distance from the cylinder is 12mm and 18mm. The calculated results are agree with the experiment results. The results show that the electrode is more closer to the cylinder, oscillation frequency becomed smaller, the value of amplitude becomed higher. On the other hand, when the cylinder is far away from the electrode, it returns to the initial vortex stripping frequency, and the frequency amplitude is hindered by the model to the vortex structure and the greater the pressure loss as the distance increases. There is no external power required and easy to detect. It can expected to become a new type of wind speed flowmeters.
|
|---|
