Flow Pattern Identification About Fluid Flow Based On The Terahertz Time-domain Spectroscopy

Single-phase flow and multiphase flow widely exists in the oil field,petrochemical,nuclear and aerospace industries,and flow pattern-the trajectory of fluid particle,the distribution of velocity or the geometric distribution of fluid particle,etc-are the very important flow parameters,which affect the mechanical properties and the characteristics of the heat and mass transfer of the flow.So the study of flow pattern,especially the judgment of the flow pattern change,is the basic studying of the fluid flow.In this paper,method of optical detection will be adopted,basing on the change of the THz time-domain spectrum characteristics,to study the flow pattern of single phase flow and different water content of oil & water two-phase flow with different flow rates in horizontal pipe.The main contents and conclusions of this paper:(1)Single-phase flow medium,composition by light diesel oil,is detected and analyzed by THz time-domain spectroscopy under different flow rates in horizontal pipe which was made by special material.The results shows that the flow rate-time domain spectrum peak value curve,which was made from THz time-domain spectroscopy,has obvious turning point.With the judgment of Reynolds number,it shows that the turning point of the curve is the flow pattern transition point.Therefore,the THz time-domain spectroscopy can be used to study the transition of flow pattern about the single-phase flow.(2)Light diesel oil & water mixtures with different water content,in which water was dispersed phase and light diesel oil was the continuous phase,were detected and analyzed by THz time-domain spectroscopy under different flow rates in horizontal pipe which was made by special material.Also the results shows that all flow rate-time domain spectrum peak value curves,which were made from THz time-domain spectroscopy,have obvious turning point.According to the characteristics of the corresponding graph of single phase flow and basing on the analysis of experimental results,it can be sure that the turning points of the curves are the flow pattern transition of the oil & water two phase flow.Therefore,THz time domain spectroscopy can be used to study the flow pattern transition of the oil & water two phase flow,or even the flow pattern transition of the multiphase flow.To some extent,of course,this two phase flow experiment may have laid a solid foundation for using THz time-domain spectroscopy to further study the flow pattern or the phase transformation of two phase flow or even the multiphase flow in the future.