Performance Measurements Of Non-newtonian Fluid Atomization Spray And Optimization Design Of Nozzle Structure

Non-newtonian fluid atomization jet technology has a wide application background in aerospace,pharmaceutical manufacturing,food manufacturing and other fields.For atomizing jet,previous studies mostly focused on external flow field in nozzle,atomizing jet medium always be Newtonian fluid.Rare global research on non-newtonian fluid gas-liquid mixed nozzle's jet flow field distribution,and few study about the nozzle internal structure's influence on the result of atomization.In this paper,the spray nozzle export external gas-liquid phase flow pattern has been experimented and simulated,the nozzle's mixing chamber structure has been designed and has carried on the experiment and numerical simulation of gas-liquid two phase flow inside internal flow pattern,then carried out an appropriate structure of the mix chamber's diferent structure simulation.The main contents of the study are:First of all,design the experiment platform for non-newtonian fluid,the main of the experiment is use the high-speed camera to take the external tflow pattern's photos.Using hot wire anemometer measured the velocity of the nozzle for external flow field in different positions.PDA(Phase Doppler Analyzer)instrument was used for different concentration of xanthan gum solution of atomized particle size measurement experiment.secondly,use the experimental data to establish the atomization model,and the field flow pattern and particle distribution of the gas-liquid two-phase flow nozzle are numerically simulated based on the DPM model.The flow field distribution of particles is simulated,the velocity field and particle field simulation results are compared with the experiment,then analyzed the mechanism of the non-newtonian fluid experimental result.Analyzes the flow field in the bubble atomizer nozzle,the conclusion is the internal flow type of air bubble atomization nozzle has a decisive influence on the atomization effect.the two phase flow of air liquid in bubble atomization nozzle wassimulated based on VOF model.Simulated the vary of air liquid-flow type when change the inlet number and the gas-liquid mixing chamber's diameter near the outlet.Then,simulation for the gas-liquid two phase flow in the gas-liquid internal mixing nozzle of different structures based on the VOF model in FLUENT.The influence of change the diameter near the outlet of the nozzle and the number of air inlet was analyzed.The time of stable circulation of different structures under different gas-liquid ratio conditions is analyzed,obtain the gas-liquid ratio and mixing cavity structure which gain the better effection of atomization.The non-newtonian fluid atomization jet internal and external flow field has been experimental measured and numerical analyzed in this paper.Flow field studies have shown that the variation trend of particle size of viscoelastic fluid and water atomization in the range of 0.05 to 0.3m was: The farther from the nozzle,the larger the particle size.And the effect of changing the gas flow on viscoelastic fluid is obviously less than that of water;The study of internal flow field shows that it can improve the atomization quality by increasing the inlet number of the mixing cavity and reducing the diameter of the outlet.