Numerical Simulation Study On Deburring Mechanism Of High-pressure Waterjet

The High-pressure waterjet deburring technology is a new Cleanliness control technology developed on the basis of waterjet processing technology.It can completes deburring and cleaning at the same time,and greatly improves the cleanliness of the parts.In the increasingly stringent cleanliness requirements for parts and components in the automotive industry,the application of High-pressure waterjet deburring technology has attracted much attention and the prospects are very broad.Understanding the processing performance of high-pressure waterjet is the key to selecting process parameters and ensuring the burr removal.In this paper,numerical simulation methods are used to study the flow field of waterjet,the impinging characteristics of waterjet,and the burr damage under the impact of waterjet.First of all,taking the free waterjet in the air as the research object,based on a large number of literature research and fluid mechanics theory,the basic structure,numerical simulation method and impinging characteristics of the waterjet are analyzed,which lays a theoretical foundation for the subsequent research.Secondly,on the basis of theoretical research,the Realizable k-? two-equation turbulent model and Mixture multi-phase flow model in FLUENT were used to simulate the waterjets generated by the designed nozzles(direct-jet type nozzle,T-type nozzle)under different jet pressure conditions.The flow field was numerically simulated.The numerical simulation results were used to study the flow field characteristics of waterjets with different nozzle structure types,and a functional expression for the relationship between the dynamic pressure and the jet distance representing the processing performance of the waterjet was obtained by fitting the experimental data.Finally,in order to study the impact characteristics of High-pressure waterjet and the failure of burrs under the impinging of waterjet.Based on LS-DYNA,using ALE method combined with Johnson-Cook material model,a fluid-solid coupling finite element model for waterjet impinging target and deburring was established.Using the parameters of the waterjet obtained by the simulation of the waterjet flow field,numerical simulation experiments were performed on the High-pressure waterjet impinging target and deburring process.The impinging characteristics of waterjet were studied by the finite element model of the waterjet impinging the target.Through the experimental results,the mathematical model of the water hammer pressure and the stagnation pressure at the impinging center was corrected by the method of statistical average and data fitting,and the expression function of the water hammer pressure and the stagnation pressure along the radial distribution of the jet was established.Through the finite element model of the waterjet deburring,the failure of the burr under waterjet impact was studied,and the burr failure mechanism under the impact of the water jet was revealed.A large number of simulation data were fitted to obtain the mathematical model of the waterjet pressure and the burr size that can be removed.