Experimental Research And Numerical Simulation On Gas Liquid Two-phase Flow

The gas-liquid reactors have broad application in the industrial fields,such as the environmental engineering,wastewater treatment,bio-chemical petroleum,energy and other fields.The urgent requirements from high efficiency and low consumption and the maximization trend of the reactors puts forward the higher demand on the gas-liquid reactors optimal design.The efficiency of the gas-liquid reactors depend on the steady flow state of gas-liquid two-phase flow inside,because the movement of gas-liquid two-phase flow can directly affect the contact and mixing of the phases in the flow field,at the same time also affected the mass and heat transfer efficiency,then expand the influence to the efficiency and consumption of the reactors.In conclusion,deeply explore with the gas-liquid two-phase flow structure hydro-mechanical behavior,the obtained results are helpful for the further theoretical research and the optimal design of the gas-liquid reactors,and it is significant for the increasingly serious problem of energy shortage and environmental pollution.In this research,the domestically developed gas-liquid reactor(Patent Number:201210051031.0)was used to carried out the experiment to research the movement of the gas liquid two-phase flow.We used the particle image velocimetry(PIV)technology and made the bubble as the particle to obtain the accurate velocity field distribution under high gas rate two-phase flow on multi-operating mode.Relying on the summary and analysis of existed gas-liquid two-phase flow model,this research mainly improves the interphase forces model,turbulence model and bubble model to establish the BPBM-CFD coupling model.By comparing the numerical simulation results with the experimental data and the previous research results,the result shows that improved model has the reliable and excellent prediction capability.The main progress and conclusions are summarized as follows:(1)Research and develop a kind of new improved measuring method used on the gas-liquid two-phase flow.With the experimental device which can eliminate the optical refraction.And use the optical method to measure the spatial-temporal distribution of gas-liquid two-phase flow velocity filed is proposed and applied to a compact transparent model of the reactor.And proposes the image processing and PIV technology to acquire the velocity filed information.(2)Process the bubble-groups population balance model to hydrodynamic calculations of two-phase flow.And thoroughly studies the mechanisms of bubble coalescence and breakup.Finally,puts forward an accelerated coalescence and breakup model.(3)Gas-liquid two-phase flow field.Based on the summary and analysis of the existing models,this research puts out the improving methods.We established the BPBM-CFD coupling model and those algorithms obtain effect preferably.(4)Based on the results of numerical simulation and experimentation,we made the optimization suggestions on gas-liquid reactors.Three impact factors,aeration rate,aspect ratio and aerators distance,are assessed to have concluded which sways the velocity distribution of two-phase flow and the operating efficiency of the reactor.The results provide theory instruction for optimization of gas-liquid reactors design.