Study On Open Channel Flowmeter Using Doppler Ultrasonic Method

The remote metering sluice gate,integrated with the remote monitoring and linkage,measurement of water level and flow and gate control,is a modern dynamic dispatching equipment of water resource,and it is also the key equipment for the construction of information irrigation area in China.It not only can improve the convenience of water resource dispatch,but also plays a significant role of saving water.Flow quantity and velocity are the most important parameters of data measurement in sluice gate system.And the ultrasonic flowmeter,which is different from the traditional flow-measuring method of open channel,is one of the main ways of current flow measurement,because it can complete measurement without building special measuring weir grooves and has the advantages of convenient installation,high accuracy and strong real-time performance.The type and measurement principle of ultrasonic open channel flowmeters are analyzed,the Doppler method is selected as a design scheme for the application of remote metering gate,and the disadvantages of current Doppler ultrasonic open channel flowmeter are optimized about its poor integration,weak real-time performance,slow dynamic response and so on.The overall design is mainly composed of hardware circuit and software:the former designs are mainly included the ultrasonic transceiver circuit,LCD 12864 display circuit,temperature acquisition circuit,liquid level measurement circuit and minimum system peripheral circuit;and the modules of software part are designed,such as module initialization,serial communication subroutine,temperature acquisition subroutine,liquid crystal display subroutine,DDS sine signal generation subroutine and AD sampling subroutine.The DSP chip TMS320F28335 produced by TI Corporation was used as a development platform for the flowmeter measurement and control,the 1 MHz pulse was used to stimulate the ultrasonic transducer,the frequency resolution of the Doppler signal was increased by the Zoom FFT method,and the performance is improved by setting threshold to reduce computation.The measurement results of Doppler ultrasonic open channel flowmeter by actual field testing and debugging of the simulating actual irrigation district are compared with the commercial open channel flowmeter.The results show that the flowmeter has stable measurement data,strong real-time performance and can be well integrated into the remote metering sluice gate system,and the desired design goals is achieved.