Flow Simulation in Abrasive Fluid Jet Machining with Water as Carrier Medium using CFD

Tremendous growth is seen in the field Machining of Materials where the engineering applications are highly demandable. Currently Abrasive Fluid Jet Machining is used to machine wide range of Engineering and Structural Materials including Aerospace, Defense and Aircraft Application which require high strength to weight and stiffness to weight ratios. In Abrasive fluid jet machining the abrasives are premixed with a suspended liquid to form slurry. The flow of the Abrasive Fluid mixture through the nozzle, results in rapid wear of the nozzle which degrades the cutting performance. This may lead to the divergence of the Abrasive Fluid Jet such that the angle of impingement varies. This jet impingement angles have more influence on the machining responses than the normal jet impingement angle as the depth of cut is improved thereby minimizing the shallow cuts within the same total cutting time. Nozzle replacement cost plays a vital role in the economics of the machining process and improvements in its wear characteristics are critical for the growth of such machining technology. It is well known that the inlet pressure of the abrasive fluid suspension has significant effect on the erosion characteristics of the inside surface in the nozzle. An analysis was carried out with constant nozzle taper angle and water as carrier medium. The objective of this work is to analyse the effect of inlet operating pressure on wall shear and exit kinetic energy with respect to Carrier medium. The two phase flow analysis was carried by using computational fluid dynamics tool CFX. The availability of optimized process parameters of abrasive fluid jet machining is limited to water and experimental test can be cost prohibitive. In this case computational fluid dynamics analysis provided better results.