Research On Detection Technology Of Two Phase Flow Parameter Based On Acoustic Emission

Research of two phase flow theory promotes the two phase flow technologydevelopment in the field of industrial application. Such as gas and liquid scrubber and gas-liquid bubbling tower, involve two phase flow system. Weather the parameters of two-phase flow can been accurate measure and realize real-time monitored in its productionprocess, which all decides the product quality and weather the equipment can be stableoperation. Due to the complexity of the flow process in two-phase flow, it is difficult toaccurate measure the related flow parameters, so research a real-time and effectivedetection method has been the development direction of the two-phase flowtechnology.Acoustic emission detection technology is an emerging method of NDTmethods in recent years, it is almost not restricted by material, it can monitor the operationcondition of the system for a long-term, and high sensitivity features, but which is difficultto achieve for other NDT methods, so the technology is highly attention by the researchersof the two-phase flow parameters detection.The flow state of the gas-liquid bubblingtower, bubble distribution and content of the gas and liquid washing tower under differentworking conditions, which are all attention by the technology design personnel, so weneed to find a method of on-line non-contact detection. So in this paper, based on theacoustic emission detection technology, do the following research about the two-phaseflow parameters:Based on the Acoustic emission detection technology and as the gas-liquid bubblingtower model is research object, according to the principle of acoustic emission signal thatproduces by friction and collision that comes from the liquid of bubbling tower to thebubbling tower wall, combined with EMD and R/S analysis method, established thepredictive model about the liquid flow state and gas content of the bubble column reactor.It can accurately identify the liquid flow state, and build the relationship between liquidflow state, gas content and the superficial gas velocity, to find the critical gas velocity.The gas and liquid washing tower model as the research object, analyses the acousticemission use signal multi-scale wavelet analysis and wavelet denouncing, reveals the acoustic emission signals’ characteristic frequencies which produces by bubbles burst ofthe washing tower, to establish the forecast model about the bubble size of the washingtower, it can quantitatively describe the changing rule of the acoustic signal energy,characteristic frequency, bubble size in characteristic frequencies. And then according torelevant position method, can clearly know where bubbles.