Design And Development Of Rust Removal Equipment Based On Cavitation Water Jet

The development and utilization of marine resources is an important topic in contemporary China and a strong guarantee for the steady operation of national economy.To this end,the state has accelerated the development and construction of marine resources development equipment.However,the coastal environment,especially that in the low-latitude sea area,is extremely harsh.It is special "three highs,one more and one strong" corrosive environment which has caused the surface corrosion and seriously affected the reliability and safety of many marine facilities.Therefore,it is urgently needed to remove rust and pretreat It's rusting surface.It is understood that the traditional rust removal method has has great pollution to environment and high cost,and is not suitable for surface rust removal of coastal equipments.In the light of the working conditions of rust removal of coastal facilities and the new requirements of operation process,in this thesis,a set of portable rust removal equipment is designed based on high-pressure cavitation water jet technology,an organ-pipe cavitation nozzle is designed,and an experimental platform is set up to conduct a large number of rust removal contrast experiments,and the optimal structure parameter combination of the nozzles and the optimal equipment process parameters are obtained.This thesis mainly carried out the following research work:(1)The research background and practical significance of this research are analyzed,the development status of high-pressure water jet at home and abroad is expounded,and the development trend of high-pressure water jet in rust removal is summarized.(2)According to the general design principles and requirements,the overall design scheme of rust removal equipment based on high pressure water jet is proposed.The type,performance and structure of the high-pressure pump are analyzed and selected.According to the actual demand of the project,the horizontal high-pressure plunger pump with pump pressure of 100MPa and flow rate of 12.7L/min was finally selected,and the model selection design of all parts required for the equipment was completed in combination with standards.(3)The cavity cavitation principle of organ-pipe cavitation nozzle is analyzed,and water acoustics and fluid mechanics related knowledge are combined to design 6 cavitation nozzles with structural data combination.4 artificial submerged cavitation nozzles were designed on the basis of organ pipe structure design to improve the efficiency of single nozzles descaling.(4)CFD software Fluent is applied to analyze the fluid field inside the nozzle.It is found that reflux occurs in the cylinder section of the organ-pipe cavitating nozzle,the surrounding area and the outlet cylinder section of the submerged cavitation nozzle,and the pressure value falls below the saturated vapor pressure,which indicates that the designed 6 organ-pipe cavitation nozzles and 4 submerged cavitation nozzles can produce cavitation bubbles.In addition,by comparing the gas phase volume fraction of the nozzle,it is found that the cavitation effect the organ-pipe cavitating nozzle labelled by 4#and the submerged cavitation nozzle with the angle of 60° are the best,and the structures are optimal.(5)"Standard erosion specimen method" is adopted to measure the erosion performance of designed organ-pipe cavitation nozzle.The rust removal experiment was designed with 304 stainless steel plate as the substrate.Under the experimental conditions,the best target distance is 15?18cm and the best erosion time is 30 seconds.The optimal structure parameters of organ-pipe cavitation nozzle are(Ds/D)2=3.83,(D/d)2=11.00,and(L/d)=2.14.The organ-pipe cavitation nozzle can be used to reruove rust in the C/D grade with the rust removal efficiency at around 4m2/h.The erosion effect of artificial submerged cavitation nozzle is better than that of the gem submerged cavitation nozzle,which can be used to remove rust in the A/B grade.And the rust removal efficiency is higher,which can reach 7.5m2/h.The rust removal surface can reach Sa2.5 grade,which meets the painting requirements.