Visualization Observation of Two Phase Flow in Abrasive Supply Tube for Abrasive Injection Jet

Abrasive injection jets (AIJs) are widely used for industrial cutting. It is known that flow pulsation will occur in AIJ with increase of the mass flowrate of abrasive particle supply. Due to the flow pulsation the cutting surface of workpiece becomes rough and the cutting performance of AIJs drops. Previous works reveal that flow pulsation of AIJ is closely related to the fluctuations of abrasive supply to nozzle head. In this work, high-speed camera observation of two-phase flow in abrasive supply tube is conducted using a model abrasive supply system. A straight tube is connected horizontally to a suction chamber and 80 mesh garnet is supplied to by using a sealed abrasive supply chamber. With increases of the mass flow rate of abrasive particles and the distance from the inlet of abrasive supply tube, distinct zones of abrasive particle concentration (dense zone) are observed in the abrasive supply tube. Image analysis reveals that the velocity abrasive particles in dense zones at downstream is faster than that in dense regions at upstream. Thus, dense zones combine while flow downstream along the supply tube.