The System Implementation Of A Micro-flow Velocity Measurement Method Based On Fluorescent Tracer Technique

The flow velocity measurement technology is an integral part of the flow studying. Although there is a lot of proven flow velocity measurement instruments, such as Pitot Tube, LDV, PIV and so on, micro-flow velocity measurement faces two problems. On the one hand, the traditional measurement instruments don't work because of low dynamic pressure. On the other hand, the advanced measurement instruments are difficult to apply in the field environment because of their complicated structure, high maintenance and operation costs. To solve these problems, this paper proposed a micro-flow velocity measurement method based on fluorescent tracer technique, the main research contents and results are as follows:First of all, this paper elaborated on the concrete implementation scheme and experimental steps of this method, completed the selection of fluorescent tracers, excitation light sources and photodiodes. Besides, a circulation water tank, driving circuits of excitation light sources and signal condition circuits were designed to complete the experiment scheme. Finally the fluorescent tracers migrating time between two detection points in a distance of L was captured by an MCU, and measured results were calculated and displayed.Then this paper revealed the basic laws of the fluorescent tracers diffusion in the water in detail, corrected the errors caused by Molecular Diffusion, thus the basic formula of this method was theoretically derived.Finally, the function of this measurement system was basically implemented in under the experimental condition of micro-flow velocity. Comparing the results to the ones measured by flow-area method, the correctness of this method was proved.