| The technology of pre-mixed abrasive water jet cleaning is a rising technology in 80s.The working process is as follows:firstly,abrasive and abrasive tank water by premixing abrasive formation in high pressure wire braided hose length again mixed and accelerated,and then through the nozzle jet,the jet to target by cleaning,reach the cleaning purpose.In this process,the abrasive has been accelerated several times,so the jet has higher energy,which is why the pre mixed abrasive water jet can be cleaned and cut under low pressure.Although the abrasive jet has many advantages,but in our country there are still some problems in high pressure water jet cleaning technology,including selection,parameters of nozzle selection is not appropriate,it will lead to low efficiency of cleaning equipment,the abrasive jet can not fully play their own advantages,so the nozzle can be said to be a core component of the equipment.In the study of the nozzle structure parameters on the impact of the jet,due to the mixture of abrasive and water belongs to solid-liquid two-phase flow,only by theoretical analysis is not enough,and through the experimental observation is difficult to get the desired results.In this paper,the numerical simulation method is used to analyze the internal and external flow field of the premixed abrasive jet nozzle.In order to explore the influence of structure parameters of different nozzle on nozzle internal and external flow field,through Gambit,Fluent,Origin three kinds of software,realize the nozzle structure modeling,numerical simulation analysis and data postprocessing.According to the results of data processing,can be summed up the different structure parameters of nozzle(cylindrical length,shrinkage angle,arc length)influence on the jet velocity,it is suitable for streamline nozzle cleaning,finally cleaning with streamline nozzle through changing the cylindrical section,nozzle length,arc length and contraction angle analysis of the influence of internal and external flow field,different cylindrical section length,arc length and the contraction angle of nozzle parameters on the other,analyzes the influence of abrasive concentration on the performance of jet,the entrance diameter is 6mm,diameter 1mm,streamline nozzle cylinder length is 6mm,the arc length is 8mm,the contraction angle is 17 degrees between the abrasive concentration between 20%and 30%is more suitable for the cleaning work.In this paper,the numerical simulation and parameter optimization are carried out,not only the axial velocity distribution and the attenuation degree of water and sand are considered,but also the velocity distribution of water and sand in different jet cross section is analyzed.Explore the influence of different structural parameters on the performance of the jet,explore more suitable for cleaning the nozzle type,in order to design a good structure and high efficiency of water jet nozzle to provide a theoretical basis. |
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