Numerical Simulation And Experimental Study On Large Eddy Of S-Bend Pipe Polished By Abrasive Flow Machining

Bend pipe is an important part widely used in various fields of industry.In the fields of aerospace,automotive,military,medical,food and other fields,the surface quality of the used parts has higher requirements.In order to deburr,round and improve the surface finish of the bend pipe,this article uses the Abrasive flow Machining(AFM)to process the curved pipe,and contributes to the development of the AFM.In this paper,the KET sub-lattice model of large eddy simulation is used to perform numerical simulation of two types of workpieces: polished S-bend pipe without side holes and S-bend pipe with side holes under different inlet pressure and abrasive concentration conditions.The results show that the inlet pressure of the S-bend pipe without side holes determines the inlet velocity of the AFM.The higher inlet pressure will significantly increase the wall shear and vortices.The distribution of the turbulence kinetic energy on the wall of the pipe become balance.When the inlet pressure is constant,increasing the abrasive concentration can reduce the speed difference between the inside and outside of the pipe.Increasing the abrasive concentration can make the wall shear and turbulence kinetic energy of the S-bend pipe more uniform.For S-bend pipe with side holes,changing in the AFM outlet has a significant effect on the movement state of the AFM in the pipe.When only one side holes are set as the outlet,a better polishing result can be produced.The conclusion of the experimental research on the S-bend pipe without side holes shows that the change of the inlet pressure and the particle size of the abrasive particle has a significant effect on the polishing.The combination of coarse abrasive and high inlet pressure will cause over-polishing.The combination of high inlet pressure and fine abrasive can obtain the best quality surface.Ra value of inner surface of the pipe can reach 76 nm.The optimal process parameters determined by experimental research can achieve the uniform polishing of the S-bend pipe without side holes by AFM.The experimental results of the S-bend pipe with side holes show that the inlet pressure has the greatest effect on deburring,rounding and surface roughness.The higher inlet pressure can obtain the better polishing results.At the end,the optimal process parameter for polishing the S-bend pipe with side holes is determined,and a roughness prediction model is established.The research results can provide theoretical guidance and data support for actual production and processing.