Design Of Thermal Anemometer Based On Temperature Sensor Array

The measurement of wind speed and direction is of great significance to our life.Due to its small size,low cost and high accuracy,the anemometer designed by the thermal wind measurement method is widely used in various fields.However,the research on thermal anemometry in our country started late,and there is still a certain gap with foreign countries,and the hand-held hot-wire anemometers currently on the market can only measure wind speed but not wind direction.Therefore,this paper proposes a new thermal anemometer method,which uses temperature sensors to design a temperature array,and designs a thermal anemometer based on temperature sensor arrays that can measure wind speed and direction.In this paper,two suitable temperature sensor arrays of cross-type and round-type are designed according to the principle of thermal temperature difference.Combining the characteristics of the array,the relationship between temperature and wind speed and direction is established,and a calculation method for wind speed and direction is proposed.An anemometer model was built in the fluid simulation software to conduct fluid simulation experiments.According to the simulation nephogram and simulation data,the feasibility of the principle of thermal temperature difference wind measurement was verified.The thermal anemometer experimental platform is built in the high and low temperature test box,and the GA-BP neural network compensation algorithm is introduced to correct the temperature drift of the sensor caused by the ambient temperature,so as to realize the temperature sensor array wind measurement.The specific research content is as follows:(1)Three major detection techniques of the thermal anemometry method are studied and the thermal temperature difference detection principle is used.Two thermal anemometers of cross-type and round-type temperature array are designed,the model is built,and the model structure is introduced.The cross-type array thermal anemometer uses two air ducts that overlap each other at 90°,each with a thermostatic heater in the center and symmetrical distribution of upstream and downstream temperature sensors;The round-type array thermal anemometer has a thermostatic heater in the center of the circle,and 32 temperature sensors are evenly distributed in the form of 4×8 arrays.Based on the orthogonal decomposition method,Gaussian distribution function method and the average value method of temperature sensors,the calculation method of wind speed and wind direction of the thermal anemometer was determined.(2)Choose Space Claim three-dimensional modeling software to model the cross-type array and round-type array thermal anemometers respectively,ANSYS Meshing software divides the model grid,and finally imports Fluent for fluid simulation analysis.The simulation results show that the temperature field is distributed symmetrically in windless condition;In windy condition,the temperature field deviates from symmetrical distribution,and both wind speed and ambient temperature will affect the indication of temperature sensor,which is consistent with the principle of wind measurement by thermal temperature difference.(3)The whole system block diagram of the anemometer is built,and the whole system is introduced from the aspects of hardware and software.The 32-channel temperature gating circuit of the thermal anemometer with circular temperature sensor array is designed emphatically.A wind-measuring platform was built in the high and low temperature chamber to collect wind speed data,and GA-BP neural network algorithm was proposed to compensate the temperature drift of the wind-measuring instrument.The experimental results show that the cross-type and the round-type array thermal anemometer have better measuring effect,and the round-type array thermal anemometer has higher precision.