Research And Application Of Hot-wire Air Flow Sensor

This paper mainly put forward to develop a simple structure, convenient use, high performance, cost-effective method of hot-wire air flow sensor,for the Status of Domestic gas flow measurement products’low precision, complicated structure, poor stability.This paper firstly introduced the gas flow sensor at home and abroad research status and development trend,based on these,our research subjects are put forward.Then we Emphasis on hardware and software design of this sensor.At last,we calibrated and measured the gas flow sensor.Hot-wire air flow sensor using Pt20and Pt1000platinum resistance sensor as measuring probe,Pt1000is the same temperature as the ambient, Pt20is constantly100℃higher than Pt1000.Gas flow through Pt20will take away its heat and thus need to improve voltage to heat Pt20,This completes the change of flow signals to electrical signals.The gas flow velocity’s calibration is completed in wind tunnel gas flow calibration system.then we can get the relationship between flow signal voltage characteristic value and real-time speed.By piecewise linear interpolation method to get the real-time speed of gas to be tested.Finally, flow signal disposal circuit realization in the industrial control standard4-20mA current linear output.The gas flow sensor designed three sets of gas flow speed measurement experiment was carried out,Experimental results show that flow sensor has a good accuracy of measurement, the full range of error are±1%within the scope of the laboratory flow speed, and three datas are consistently, the flow sensor has a good reliability and repeatability.