Ultrasonic Gas Flowmeter Based on Dynamic Reference Waveform Cross-Correlation Algorithm

The ultrasonic signal attenuates greatly in the gas medium and is easy to be polluted by acoustic noise, the periodic error may appear in the ultrasonic transit time detection when threshold method is used. In this paper, the cross-correlation algorithm is used to detect the ultrasonic transit time. In which, the real-time dynamic reference waveform is used to perform cross-correlation operation with the received waveform. It is different from the echo method or the static average reference waveform method, the real-time dynamic reference waveform can effectively overcome the correlation decline caused by environmental factors. Temperature test and calibration test of sonic nozzle gas flow standard device are carried out on the self-designed ultrasonic gas flowmeter. The test results show that the method has good measurement accuracy and environmental adaptability.