Multi-stage diffuser nozzle

摘要

A multi-stage diffuser nozzle for use as a drill bit nozzle jet includes a flow restriction portion upstream of a fludic distributor portion, and also preferably includes a transition region between these two. The flow restrictor communicates with the interior fluid plenum of a drill bit and is used to limit or choke the total flow of drilling fluid by having a relatively small cross-sectional area for fluid flow. The fluidic distributor communicates with the flow restrictor and reduces the exit flow velocities of the drilling fluid as the drilling fluid is ejected from the nozzle by providing a relatively larger cross-sectional area for fluid flow. The fluidic distributor also directs the flow paths of the drilling fluid to locations such as cone surfaces that are prone to bit balling. The transition region is an area that dampens fluid pressure oscillations in the drilling fluid.