A Method For Determining The Mixing And Mixing Time Of A Gas-liquid Two-phase Flow Based On Image Processing

In the process of nonferrous smelting,the metal or minerals in the reactor are in a molten state,the gas phase or liquid phase as the continuous phase,they are coexisting with the metal or minerals,the traditional laboratory study and field observations have been unable to meet the needs of development of the new situation.In order to obtain the information which can’t be obtained by the mixing process and save the experiment cost,it is an important content in the field of metallurgy to reveal the phenomena and laws in the process of mixing pool by mathematical simulation and physical simulation.This paper is focus on the measurement of mixing time of gas-liquid two-phase flow in stirred tank,digital image processing technology,computational homology group theory,gray delaminating and RGB color model.By building the experimental platform of hydraulics experiments by top-blown gas stirring and mixing,firstly,the image that captured in the mixing process is processed by image processing,convert image information into digital information.Secondly,using the mathematical analysis method to analyze the characteristics of the digital information,to determine the mixing characteristics of the mixing process.Content mainly involves designing hydraulics experiments of gas-liquid two-phase flow,the method of modified Betti,gray delaminating and RGB color model to measure the mixing time of gas-liquid two phase flow,influence of injection conditions on mixing time and the study of using the method of gray delaminating to the mixing experiment of side-blown gas stirring.Based on the three phase reaction model of CH4 and ZnO in molten salt,building the experimental platform of hydraulics experiments by top-blown gas stirring and mixing.nitrogen is used to simulate the gas phase(CH4),Water is used to simulate the liquid phase(molten salt)in chemical reactors,and black polystyrene particles with diameter 0.45 mm are used to simulate the solid phase catalyst(ZnO).To presented the method of modified Betti,gray delaminating and RGB color model to measure the mixing time of gas-liquid two phase flow.Through the design of experimental conditions of different spray gun’s insertion depth L(cm)and flow rate Q(L/h)to effect the mixing time.Using three kinds of measuring method is proposed in this paper to measure the mixing time of the hydraulics experiments by top-blown gas stirring.The feasibility and validity of the three new methods are verified by electrical conductivity.While using the method of gray delaminating to the mixing experiment of side-blown gas stirring,it is proved that the method of gray delaminating is universal.The results show that to determine the mixing time in stirred vessels based on the law of distribution of tracer particles,the method of modified Betti to overcome the influence of bubbles on the distribution of tracer particles.the method of gray delaminating to extract the 2D image of each pixel in the 3D information,thereby more accurate analysis of the present steps particle distribution information,the method of RGB color model can extract more image information in color images,overcome based on binary images and grayscale images,when the blending time is measured image information leakage problems.A new insight is provided to solve the engineering problem such as various multiphase mixed effect and some experimental basis are offered to improve the life span of the molten pool,strengthen its smelting production and optimize its technological process.