Investigation on Gas-Liquid Two-Phase Pressure Drop and Recurrence Characteristics across an In-Line Tube Bundles

A comparative analysis of pressure drop of different flow pattern of two tube bundles was done. The results show that: the pressure drop of bubble flow is maximum, followed by intermittent flow, and mist flow becomes the minimum. Based on the statistical analysis of the different pressure signals, the power spectrum density versus frequency of the signals for major flow patterns was obtained. It is found that the flow patterns can be identified in accordance with the power spectrum density. The recurrence quantification analysis method was used to study the dynamic characteristics of differential pressure fluctuating signals of bubbly flow, intermittent flow, mist flow patterns. The research indicated isolated points texture appeared on recurrence plot for the bubbly flow. Both dispersed points texture and massive texture appeared on recurrence plot for the intermittent flow with strong chaos characteristic. The recurrence plot of mist flow whose idicated periodic is outstanding has a good diagonal texture. The recursion texture of differential pressure fluctuating signals could well reflect the evolution characteristics of flow pattern, and the recurrence characteristics quantities were obvious to the variations of superficial gas velocity and provided a new idea for investigation of gas-liquid two-phase flow mechanism.