Gas–liquid two-phase flowrate measurement in pseudo-slug flow with Venturi. (April 2021)

• Record Type: Journal Article
• Authors: Wu, Haitao; Xu, Ying; Wang, Jinghan; Yang, Yiguang; Li, Tao; Zhang, Tao; Li, Jianli; Hao, Chongzhi
• Is Part Of: Flow measurement and instrumentation. Volume 78(2021)
• Publication Date: 2021-04
• Subjects: Pseudo-slug flow -- Venturi -- Differential pressure -- Wavelet transform -- Volume gas holdup -- Flowrate model; Fluid dynamic measurements -- Periodicals; Flow meters -- Periodicals; Fluides, Dynamique des -- Mesure -- Périodiques; Débitmètres -- Périodiques; 681.2805
• DOI: 10.1016/j.flowmeasinst.2021.101887
• Languages: English
• ISSNs: 0955-5986

Abstract

Abstract: The importance of pseudo-slug flow research is becoming increasingly prominent in the petrochemical field. But the gas–liquid two-phase flowrate measurement in the pseudo-slug flow has not been properly understood and modeled. Based on the differential pressure of Venturi, this study proposes a new pseudo-slug flowrate prediction model. By means of Fast Fourier transform (FFT), the representative frequency range (3.125 Hz < f < 6.25 Hz) is determined. Then, the fourth detail component of the differential pressure after wavelet transform is selected as the flag to distinguish the liquid film region and the pseudo-slug body region. Based on the gas–liquid density ratio, a logarithmic model is established to predict the threshold value. In the liquid film region, the gas–liquid two-phase flow is regarded as wet gas and the flowrate is measured through the over-reading model. In the pseudo-slug body region, the volume gas holdup model is established based on the fluctuation information of the differential pressure. Then the gas–liquid two-phase flowrate can be obtained by solving the Bernoulli equation. Compared to the experiment, the confidence probability of ±10% relative deviation band is 97.78% for the gas, and the confidence probability of ±20% relative deviation band is 95% for the liquid. Highlights: A novel flowrate model is proposed for gas–liquid pseudo-slug flow with Venturi. The liquid film and pseudo-slug body region is distinguished by analyzing Δ P . A threshold value logarithmic model on the gas-liquid density ratio is established. A volume gas holdup model on the fluctuation information of Δ P is established.