基于时差法的外夹式超声波流量检测系统的设计与实现

Design and Realization of External Clamping Ultrasonic Flow Detection System Based on Time Difference Method

摘要:

外夹式超声波流量计因具有无需破坏管道、便于安装、维护成本低等优势，而广泛应用于石油传输、流量跟踪、给排水等测试领域。设计了一种基于时差法的外夹式液体超声波流量检测系统，采用FPGA与单片机结合的系统架构，其中单片机负责数据的处理、显示和输出，FPGA负责逻辑控制以及为硬件电路提供驱动信号，TDC-GP22高精度计时芯片用来测量超声波的渡越时间。采用DAC电路实现可变甄别信号基准技术。最后，搭建了外夹式超声波流量计测试平台，试验结果表明，研制的样机有效地提高了超声波流量计的测试精度，在层流区误差小于4%，在湍流区误差小于2%。

Abstract:

The clamp-on ultrasonic flowmeter is widely used in the testing fields of petroleum transmission, flow tracking, water supply and drainage because of its advantages such as no need to damage the pipeline, easy installation, and low maintenance cost. A clamp-on liquid ultrasonic flow detection system based on the time difference method is designed. It adopts a system architecture combining FPGA and single-chip microcomputer. The single-chip microcomputer is responsible for data processing, display and output, and FPGA is responsible for logic control and providing drive signals for hardware circuits. TDC -GP22 high-precision timing chip is used to measure the transit time of ultrasound. DAC circuit is used to realize variable discrimination signal reference technology. Finally, an external clamp-type ultrasonic flowmeter test platform was built. The test results show that the developed prototype effectively improves the test accuracy of the ultrasonic flowmeter, with an error of less than 4% in the laminar flow zone and less than 2% in the turbulent flow zone.