Simulation and analysis of flow field in abrasive water jet nozzle

Numerical simulation of flow field inside abrasive water jet nozzle on steady, turbulence, two-phase flow conditions was carried out based on FLUENT. The main geometric parameters of abrasive water jet nozzle were analyzed. The results show that the smaller the contraction angle a of the focusing tube, the better flow field inside abrasive water jet nozzle is. Also smaller contraction angle avoids abrasive gathering at the entrance of the focusing tube. The smaller the outlet diameter of focusing tube, the greater velocity of the abrasive can be obtained. On the other hand, the smaller the outlet diameter of focusing tube is, the smaller negative pressure inside the mixing chamber exists. Consequently abrasive inhalation is not good. Outlet diameter of focusing tube should be in the range of 3 times of the jewel orifice. The results show also that the length of the focusing tube has significant effect on the outlet velocity of abrasive. In order to achieve maximum speed of abrasive, the length of cylinder part of focusing tube should be in the range of 30 times of the outlet diameter. Simulation of flow field inside abrasive water jet nozzle and analysis of parameters of the focusing tube provide basis in design of nozzle for abrasive water jet.