Reference frequency variance-based rapid identification method for vortex flow rate under mixed vibration interference

Pipeline systems in industrial applications may encounter strong mixed vibration interference, resulting in measurement errors of vortex flowmeters. Current research primarily addresses single types of vibration interference. Various signals output by vortex flow sensors under diverse operating conditions were analyzed to tackle the issue of mixed vibration interference. The amplitude and frequency characteristics of transient impact-type interferences were studied. The differences in frequency fluctuations between periodic interferences and periodic signals were investigated. Then, a method based on reference frequency variance was proposed to resist mixed vibration interference. The primary calculation load of this method arises from the execution of Fast Fourier Transform (FFT). To meet the instrument requirements of low-power consumption and real-time performance, a multipoint FFT method based on a low-power accelerator built-in microcontroller was proposed, which remarkably improved the calculation speed of multipoint FFT and conserved storage space. The reference frequency variance-based antimixed vibration interference algorithm was implemented in real time using a low-power vortex flowmeter system developed by our team, and an antimixed vibration interference gas flow verification experiment was conducted. The method can accurately identify vortex flow signals when the interference energy of the periodic type and the main mode energy of the transient impact surpasses the energy of the flow signal.