Research On Mixing Characteristics Of Gas-liquid Two-phase Flow Based On Digital Image Analysis

During the melting process of the bath,the metals or minerals in the stirred reactor are in a mixed state.The gas phase and the liquid phase coexist.Traditional laboratory methods and field observations are far from meeting the development of the new situation.In order to obtain the information of the mixing process in the molten pool and save the experimental cost,it is an important content in the field of metallurgy to use the physical simulation method to reveal the phenomena and laws in the melting process of the molten pool.This article takes the mixing effect of the fluid i n the gas-liquid stirring reactor as the research object,and combines the digital image processing technology,the computational coherence group theory,the homogeneity measurement theory and the chaos identification theory to design the gas-liquid two-phase mixed hydrodynamic model experiment.First,capture the color experimental image of the gas-liquid mixing process and combine the digital image processing technology to process the experimental image.Secondly,the image data of the gas-liquid two-phase flow was studied by combining the mathematical method of image segmentation algorithm,Betty number calculation procedure,star deviation and 0-1 test method,and the experimental image data was studied.The research contents mainly involve the design of gas-liquid two-phase mixed hydrodynamic model experiments,the influence of gas injection conditions on the mixing effect,the measurement of the mixing time by Betti numbers method and deviation method,and the chaotic behavior of the 0-1 test method to characterize the flow field.The main conclusions are as follows:(1)The Betti numbers method and the deviation method were used to study the mixing effect of the top-blown mixing hydrodynamic model experiment.The effect of the insertion depth l(cm)and the injection gas Q(L/h)on the mixing effect of the flow field was investigated.The above two mathematical methods were used to determine the mixing time to evaluate the mixing effect of the experimental conditions.The standard deviation sequence was used.The average value as a comparison method verifies the effectiveness of the two methods.(2)The efficient operation of a multiphase stirring system can produce a highly nonlinear chaotic mixing phenomenon.The 0-1 test method was introduced and verified for its effectiveness.The fluid chaotic characteristics in the gas-liquid mixing interface region in the bottom-blown mixing hydrodynamic model experiment were taken as the research object,and the digital image processing technology was used to extract the characteristic gas content of the bubble image.Consider the influence of the spray gun arrangement on the behavior of chaotic mixing in the flow field.The 0-1 test was conducted on the gas holdup time series of the six groups of work conditions.It was found that the 0-1 test method can distinguish the chaos strength of different mixing processes to some extent.(3)The median value of K_c ranges from(0,1).When the median value of K_c approaches 1,the time series has chaotic characteristics.The median K_c in the 0-1 test can distinguish the strength of the chaotic characteristics in the stirred reactor and optimize the arrangement of the spray gun.At the same time,it provides a new test method for chaotic mixing of fluids in various types of stirred react ors,which can provide important theoretical basis for online applications and enriches the visualization of flow fields to some extent.