Multi-scale recurrence quantification analysis of the dynamic characteristics of two phase flow pattern

Based on the conductance fluctuating signals of the gas/liquid two phase flow measured in a vertical upward pipe, the multi-scale recurrence quantification analysis method is used to study the dynamic characteristics of gas/liquid two phase typical flow patterns. The results show that the low frequency bubble and churn flow patterns take on more developed line texture structure along the diagonal direction of the chaotic recurrence plot, which indicates that the low frequency bubble and churn flow have deterministic motion behavior. However, with increasing motion frequency of bubble and churn flow, the chaotic recurrence characteristics become worse and the motion tends to random gradually. For the slug flow, the intermittent rectangular massive texture appears on chaotic recurrence plot, which indicates that the intermittent motion characteristics of the liquid plug and gas plug appear in the high frequency band, whereas bubble flow motion in slug flow pattern appears in the low frequency band, and with increasing motion frequency of bubble flow, the bubble flow loses the deterministic behavior gradually. It is shown that multi-scale and nonlinear analysis based on conductance fluctuating signals is an efficient approach to understanding and characterizing the dynamic characteristics of gas/liquid two phase flow patterns.