Numerical And Experimental Investigation On Movement Of Microparticle In Jet Flow

The application of the study of micro-particle motion in the jet flow is very extensive.The basic research of atomization spray has more attention in recent years,including the movement of the solid flow and the liquid flow in the jet.The spray atomization is widely used in the field of manufacture of high quality materials,energy,chemical and other fields,such as the jet coating of diamond in the turbine engines,the coating of alumina powder in the fuel cells,and the manufacture of fabric materials with a variety of performances and so on.The main contents of this paper include numerical simulation part and experiment part.The jet characteristic of gas-liquid flow and gas-solid flow is researched in the numerical simulation part.The particle generator is designed and made.Meanwhile the experiment in the jet is conducted.Specific contents are as follows:(1)The basic equations of fluid motion in the jet field are described in this paper.The jet field geometry is established.The k—? model and the Large Eddy Simulation model is adopted to analysis the jet characteristic in the computational model.The velocity contour and the velocity distribution curve are obtained by the numerical simulation.The vortex is clear in the jet field from the maps.(2)A set of reconstructed equations used in gas-solid jet is adopted to simulate the gas flow.The source terms in the equations are modified through a user-defined function(UDF),while the force on the particles is written in the UDF based on Newton second law.The trajectory curve and velocity distribution at the different positions of the particles are obtained under different inlet air velocity.The relationship between velocity,position and flow field is gotten in this part.(3)Analysis export concentration distribution characteristic under the different conditions of inlet velocity,outlet height and outlet contraction angle in the numerical simulation for the gas-solid flow.The results show that with the higher inlet air velocity,the mixing speed becomes faster,the largest export volume fraction decreases and the duration of the maximum volume fraction increases.With the higher outlet height the volume fraction changes a little.With the higher outlet contraction angle the maximum volume fraction decreases and the mixing effect weakened.(4)The particle generator is designed and produced.The analysis of the advantages and disadvantages of the device provides the experimental basis for theoretical studies of gas-solid jet field.The experiment for the gas-liquid flow in the jet uses the PIV test system.The jet structure in the experiment is disordered,but in line with the flow characteristics of the jet.Based on the jet structure analysis,the particle motion analysis in the jet flow and experiment analysis,this paper summarizes the basic characteristics of the jet and the particle laws of motion,provides a theoretical basis and experimental support for the further study of tiny particles movement in the jet.