Injection into a viscoplastic medium : an experimental study

Abstract

Jets and microjets play multiple roles in various engineering applications and numerous natural phenomena. In the current research, we conducted experimental investigations to deepen our understanding of the fundamental aspects of microjet injection into viscoplastic media and the transition from jet to microjet. Specifically, we have explored the influence of the injection velocity, nozzle diameter, and ambient fluid properties on the laminar length (i.e., the length of the stable region of the jet after injection from the nozzle) and penetration depth (i.e., the maximum depth into the ambient fluid that the jet fluid can spread in the axial direction) of the jets and microjets. In order to more fully grasp the fluid dynamics, we have identified and analyzed the governing dimensionless parameters, including the Reynolds and Bingham numbers. Our findings reveal that the laminar length and the penetration depth are a function of both the Reynolds and Bingham numbers. Also, an increase in the Reynolds number leads to a corresponding increase in the penetration depth.