| Micro-flow velocity measurement is closely related to the studying of the water movement in peaceful lake, small flow in the pipeline and slope flow. Micro-flow velocity measurement in field environment is a problem all the time, although there are many proven flow velocity measurement instruments.For one thing, the traditional measurement instruments fail to work because of low dynamic pressure. For another, the LDV is not suitable in the harsh field environment for the sake of the difficulty in maintaining. Therefore, the laboratory proposed a micro-flow velocity measurement method based on fluorescent tracer technique. And this paper improved this method and designed and implemented micro-flow velocity measurement system based on fluorescent tracer technique.Firstly, migration model and diffusion model of fluorescent agent was established in this paper through the studying of the migration law in the water. And then, according to the diffusion model, the migration velocity of fluorescent agent was analyzed due to the diffusion coefficient in this paper.At last a theoretical method to calculating the diffusion velocity was proposed.Secondly, the original experimental provision and hardware circuit was improved in this paper.Especially. In order to enhance the anti-interference ability of system, the modulation circuit of luminescence diode was designed. And, with the purpose of improving automation of system, automatic delivery device of fluorescent agent was designed in this paper. Meanwhile, remote monitoring was realized for field monitoring without people in this paper.Finally, the circuit of the system, automatic delivery device and remote monitoring was tested in this paper, which verified the reliability of the system Through measuring the diffusion velocity of fluorescent agent in the water, the measuring result was more accurate and less error compared with the original data and the ones measured by flow-area method. |
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