Matching Design And Performance Research Of Pre-mixed Abrasive Water Jet System

Today,high pressure abrasive water jet cutting plays an important role in the cutting field.Compared with the traditional cutting methods,high pressure abrasive water jet cutting has unique advantages of no cutting thermal deformation and wide cutting material range.High pressure abrasive water jet cutting technology is a kind of cold cutting technology,which develops rapidly in various fields with its unique advantages.First of all,the advantages and disadvantages of the pre-mixed high pressure abrasive water jet and the post-mixed high pressure abrasive water jet were compared.Finally,design the pre-mixed high pressure abrasive water jet cutting system.In this paper,the overall scheme of the pre-mixed high pressure abrasive water jet cutting system was designed,and the pressure loss in the system and the influence factors of the high pressure abrasive water jet cutting were analyzed.Cutting nozzle is the key component of high pressure abrasive water jet cutting system.The solid-liquid two-phase flow field based on the FLUNENT numerical simulation software in the cutting nozzle was simulated,and the result is that: the water jet formed by the straight cone nozzle has a longer length of the potential core,the pressure loss is small,and the nozzle structure is easy to be processed.So it is the best choice for the pre-mixed abrasive water jet nozzle.Then,the influence of different size parameters of the conical nozzle on the abrasive water jet was studied.It can be concluded that: When the contraction angle is 14 degrees,the velocity of nozzle outlet water and sand is the largest,the constant potential core is the longest,and the pressure loss is the smallest.So the choice of contraction angle of 14 degrees is the best.When the ratio of length to diameter l/d is chosen,it is necessary to avoid the insufficient acceleration caused by the short length and to avoid the energy loss caused by the excessive length of the straight column.So the ratio of length to diameter of nozzle is 4<l/d<6.The mixing chamber is another key component of the high pressure abrasive water jet cutting system.The internal flow field is liquid-solid two-phase flow,and the flow form is complex.The FLUENT simulation software was mainly used to simulate the flow field in the interior of the mixing chamber.The conclusion is that: when the diameter of the mixing chamber nozzle is d=2.5mm,the mixing chamber conforms to the pressure matching condition of the sand mixing system;when the area ratio is R=2 and the nozzle position is Le=2D,the mixing effect in Sand chamber is best.Finally,research on abrasive particle impacting metal materials in abrasive waterjet cutting was carried out to understanding erosion mechanism.The finite element software ABAQUS was used to study the impact process of spherical abrasive particles on metal targets at different impact angles.The correctness of the simulation results was verified by comparing with the experimental results.Then,the effects of the abrasive speed,the diameter and the shape of abrasive on the erosion rate and erosion depth were studied.Some conclusions obtained in this article provide a reference for future research and design of high pressure abrasive water jet cutting,and future research work is prospected.