Research And Development Of Cavitation Jet Device

Cavitating jet technology is a new type of jet technology.Compared with traditional water jet technology,cavitating jet technology enhances the erosion effect with the powerful impact of cavitation bubbles collapse.It has the characteristics of high efficiency,environmental protection and low consumption.In order to better apply cavitation jet technology in production practice and improve industrial production efficiency,based on the theory of cavitation,the cavitation process is simulated and the parameters of the nozzle are optimized.A complete set of jetting device is designed and fabricated,and the cavitation experiments were carried out to verify the efficiency of the cavitation jet and the feasibility of the experimental device.This dissertation consists the following parts:?1?The cavitation characteristics of the nozzle were analyzed,and the diameter of the throat d,inlet p₁ and outlet pressure p₂,outlet diameter D and outlet length H were simulated by Fluent.The simulation results show that d affects the pressure drop of the throat jet and the length of the high-speed sustaining section,p₁ and p₂ affects the initiation ability of the cavitation.D has a greater influence on the jet outlet pressure than H.A set of nozzle parameter ratio d: D: H = 1: 8: 8 was obtained by comprehensive comparison,which provided the basis for nozzle parameter design.?2?A complete set of cavitation jet is designed and built.The motor,piston pump,measuring instruments,valves,high-pressure hose and so on are selected.The cavitation nozzle,working water tank,integral support and erosion target are designed and manufactured,and the nozzle is designed with segment size.Finally,the whole device is installed and debugged.?3?The cavitation experiments were carried out with different parameters which affect the cavitation performance.The experimental material was 5052Mg-Al alloy.When d = 1.2-2.0mm,the nozzle flow coefficient increases first and then decreases with the decrease of d.When the p₁ = 8-10 MPa,S = 60-80 mm,the cavitation erosion is best.With the increase of p₁,the erosion rate decreases,the diameter of the erosion circle and the cavitation intensity first increase and then decrease.With the increase of S,the erosion rate increases,the diameter of the erosion circle and the cavitation strength increase first increase and then decrease.The best erosion time t is different under different pressures,when d = 1.6mm,p₁= 5-12 MPa,the best erosion time is between 75-105 s.In the experiment of jet application,a small diameter erosive spot was obtained by high pressure water jet,and the cavitation and the cavitation in addition to paint and cavitation of rust experiments were all effective erosion areas similar to aluminum alloy erosion.