Research On Multi-Variable-rate Open Channel Automatic Flow Measurement System Based On Area Velocity Method

China is a large agricultural country,and agricultural water accounts for the largest proportion of total water consumption.In order to solve a series of problems in agricultural irrigation,China has carried out large-scale irrigation district standardization projects and water-saving transformation projects to make the improved irrigation channels transmission and distribution Most of the water channels are standardized channels,which facilitates the development of new and precise water measuring facilities.With the development of water conservancy informatization and the gradual improvement of agricultural water use efficiency,automatic real-time accurate measurement of open channel flow is imperative.On the basis of previous studies,this paper uses modern water conservancy information technology to design a multi-resolution open channel automatic flow measurement system based on the area velocity method.The system mainly includes stepper motor,bi-custodian,mechanical motion mechanism,circuit hardware system and host computer control system.In order to improve the accuracy and automation level of flow measurement,and at the same time reduce the overall cost of the system,the flow measurement system uses single-chip control technology to achieve automatic measurement of open channel flow.The specific flow measurement process is to collect flow rate information through Pitot tube and differential pressure sensor.The software of the host computer calculates and processes the collected data,and displays the obtained flow data through the human-computer interaction interface of the host computer.The specific research contents are as follows:(1)The design of the overall scheme of the multi-resolution open channel automatic flow measurement system using the area velocity method.(2)Designed and produced the mechanical structure of the flow measurement system,especially the two-dimensional kinematic structure fixed with Pitot tube.(3)Designed and produced the hardware circuit system of the automatic flow measuring device.There are 7 units in total,namely the main control unit,stepper motor drive unit,interrupt trigger unit,GPRScommunication unit,ultrasonic distance measuring unit,IIC communication unit and power supply unit.(4)The application program of the automatic control system is written in C language,and the software program of the host computer is written in Qt language,and the entire system is debugged.(5)The experiment was conducted on the rectangular channel of the water flow test hall,and the experimental data was analyzed to verify the accuracy and applicability of the flow measurement of the system.