The Research On Multi-path Ultrasonic Measurement Of Gas Flow Rate Based On Time-difference Method

Along with the continued technology development, people’s living standardgenerally has enhanced. A mount of high-technology products are used in differentdomain. High-technology products have changed people’s life and improved people’ workefficiency. For example, the product of ultrasonic flowmeter serving as gas flowmeterwhich helps measuring diversified gas flow rate records in the aspect of ultrasonic flowmeasurement. A gas ultrasonic flowmeter is suitable for measured multiple gas. It has longoperating life and alternative of high dangerous work.The ultrasonic flowmeter of this paper selects time-different method for measuringprinciple. The ultrasonic flowmeter by means of measured the time difference betweentime and tide in gas that determined the flow velocity of fluid. Firstly, the topic willrecommend the whole situation of ultrasonic flowmeter and then contrast the principle ofmeasurement of many flowmeters and analyses time-different method for measuringprinciple in details. Recommending the principle and type of ultrasonic transducer, AT200transducers of Airmar corporation are selected after analysis. The system confirms themeasuring method of multichannel by use of signal detection and measuring principle.Make use of multichannel to capture the cross section information.The total designation of the system is introduced. This system combines hardwarewith software. The hardware contains driving circuit, receiving ultrasonic signal circuit,analog switch and power module. The software of system chooses FPGA. FPGA runsquickly. It has integrate PLL that could frequency double external clock. Its centrefrequency could arrive at hundreds of MHZ what might to measure the transfer time ofultrasonic more accurate and thus increase the measuring accuracy. Its design task isdivided into providing original pulse signal for driving circuit, sending control signal foranalog switch, counting and memory, eliminating error and data display module, et al. TheThrough the reasonable hardware and software debugging, setting up a velocitymeasurement testing equipment for a gas ultrasonic and measuring velocity data of two different pipe diameter and two different installation method. Finally, processing andanalysis the experimental data.