Hilbert–Huang transform (HHT) based analysis of signal characteristics of vortex flowmeter in oscillatory flow

Abstract

In this paper, firstly, on an experimental facility, we investigated the measurement characteristics of a diameter 50 mm vortex flowmeter in steady flow and oscillatory flow. Then, the Hilbert Huang Transformation (HHT) method was used to reduce vortex flowmeter signal noise in oscillatory flow. Offline simulation was carried out on the de-noising of the vortex flowmeter in oscillatory flow by the method of the EMD-scales filter. The de-noising effect was assessed by signal-to-noise ratio (SNR) and relative error of the main frequency between the noisy test signal and reconstructed signal. The major findings are: (a) In a wide range of volumetric flow rate (Q) and the imposed disturbing frequency (f), the EMD-scales filter performs effectively and excellent filtering capability for vortex flowmeter in oscillatory flow. (b) In a specific range of volumetric flow rate (Q) and the imposed disturbing frequency (f), the EMD-scales filter performs ineffectively for vortex flowmeter in oscillatory flow. (c) The invalid condition of the EMD-scales filter for vortex flowmeter in oscillatory flow was advanced in this paper.