Study On Identification Of Gas-liquid Two-phase Flow Patterns Based On The Complexity In The Double-contact Absorber

Gas-liquid two-phase flow in the double-contact absorber is a new type flow，whichis mainly used in the area of chemical and pollution control in coal-fired power plant.Flow patterns have a significant impact not only on the gas-liquid two-phase flowcharacteristics, but also on heat and mass transfer characteristics. Therefore, study onidentification of gas-liquid two-phase flow patterns has important academic value and issignificant for the practical project.Firstly, the differential pressure transmitter was used to collect differential pressuresof the Gas-liquid two-phase flow in the double-contact absorber, and the data acquisitiondevice was used to collect differential pressure signals. From fluctuations in the images,it can identify that the double-contact absorber has four typical flow patterns: bubblyflow, liquid-column flow, disorder flow and whirlpool flow. The results show that: thedifferential pressure fluctuations of bubbly flow and liquid-column flow is relativelystable and have lesser amount of variation; the disorder flow have a large range ofdifferential pressure fluctuations, the gas-liquid mixture is uniform; although whirlpoolflow have a maximum range of fluctuations, but it is a mutation which is unstable.Secondly, the high-speed video camera was used to photograph the flow ofgas-liquid two-phase in the double-contact absorber. Gray histogram and grayscaleaverage was obtained by processing these images and then constituted the time signalsequences. Three methods were used for analyzing the complexity which wereLempel-Ziv complexity, approximate entropy and sample entropy. The results show that:disorder flow has maximum entropy and highest degree of complexity; whirlpool flowfollowed; bubbly flow and liquid-column flow have lowest degree.Finally, from the comparison of two flow pattern identification methods, it canobtain same results between the differential pressure fluctuation method and complexitymethod. The deviation of the former is larger，the deviation of the latter is smaller and theresult is more accurate than the former. Theoretically speaking, it provides a new idea forthe study of intelligence flow pattern identification about taking the method ofcomplexity to identify the gas-liquid two-phase flow patterns in double-contact absorber.