Numerical Simulation And Experimental Study Of A Compound Abrasive Water Jet Descaling Nozzle

In the face of increasingly tense environmental problems,changing the processing methods with serious pollution has become the key to the development of the manufacturing industry to adapt to the times.Post-mixed abrasive waterjet descaling technology is widely used in steel mill descaling operations because of its pollution-free,clean and efficient,and high safety,but the traditional post-mixed abrasive waterjet always faces problems such as unsatisfactory mixing of abrasive slurry and highspeed water beam,low jet beam energy,and poor descaling effect.Based on the traditional post-mixed abrasive waterjet nozzle,combined with the characteristics of pre-mixing abrasive waterjet nozzle,this paper proposes a tandem abrasive waterjet nozzle with double mixing cavity type,and through numerical simulation and experimental research on the two nozzles,it is confirmed that the overall performance of the proposed tandem abrasive waterjet nozzle is better than that of the traditional postmixed abrasive waterjet nozzle,and the energy of the outlet jet beam,the mixing of the abrasive slurry and the high-speed water beam and the cleanliness of descaling are greatly improved.Its main research contents include the following:(1)The traditional post-mixed abrasive waterjet nozzle and the proposed tandem abrasive waterjet nozzle are pre-processed such as threedimensional model establishment,runner calculation domain extraction,structured meshing,and mesh independence verification.Then,the solution model was reasonably selected,the boundary conditions and material properties were set according to the actual working conditions,and the two nozzles were numerically simulated using Fluent software.(2)The numerical results of the two nozzles(abrasive volume fraction,jet velocity,jet pressure,jet density,turbulent kinetic energy,etc.)were analyzed and compared separately.The traditional post-mixed abrasive water jet nozzle is too different from the speed of the abrasive slurry and the high-speed water beam,and it is difficult for the abrasive to enter the core area of the high-speed water beam,and a large number are distributed on the surface of the water beam,resulting in the nozzle jet energy is not concentrated and the jet power is low.The tandem abrasive waterjet nozzle adopts a double mixing cavity structure,which improves the mixing of abrasive particles and high-speed water beam,improves the energy and efficiency of the jet beam,and concludes that the jet pressure at the outlet center is 1.2 times that of the traditional post-mixed abrasive waterjet nozzle,and the jet density at the outlet center is 1.6 times that of the traditional post-mixed abrasive waterjet nozzle.(3)The descaling test of two nozzles was carried out to verify the correctness of the numerical calculation.The two kinds of nozzles were installed on the same test platform,and randomly selected 4 groups of test results for comparison.The test results showed that the surface of the tandem abrasive water jet nozzles after descaling was brighter and brighter,and the roughness was smaller.The results of electron microscope scanning(SEM)and energy spectrum analysis also show that the combined abrasive water jet nozzle has higher surface cleanliness and less impurity elements after descaling.