| Summary: | 碩士 === 國立彰化師範大學 === 機電工程學系 === 102 === In recent years, flow meter in the laboratory and industrial related field are important in measuring instruments. Based on different physical principles, tens of models that work in harmony with the diverse environmental demands and measurement conditions are developed to date, For example: Cup anemometer, Hot wire anemometer, Ultrasonic anemometer, Pressure anemometer, Laser Doppler anemometer, etc..
The article is focused on exploration of the analysis of experimental results of hot wire anemometer under different conditions. We provide a new idea that different from traditional hot wire, using an additional hot wire that will not affected by wind, thoroughly analysis double hot wire and sense the future of differential signal structure, then gain the measurement with low interference and high sensibility.
Changing the value of the internal resistance of the bridge circuit and replace one of the hot wire resistors instead, become the double hot wire circuit. The bridge circuit is also changed from the Constant-Temperature model to Constant temperature difference mode.And set as a simulated experiment under wind speed 1m/s~6m/s, analysis of power consumptions, noise rations and sensitivities base on the setting of different resistance difference, different temperature.
It was found that the smaller temperature difference of dual hot-wire, the higher operation temperature of hot-wire, and better sensitivities, but bring about high output voltage and high power consumption. Comparison of these two mode, Constant temperature difference mode can reduce the hot-wire output power, energy saving and reduce noise rations, improve stability.
Keywords: hot-wire anemometer, bridge circuit, double hot-wire circuit, Constant-Temperature model, Constant temperature difference mode.
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