Studies in recent years with the progress of experimental means , the technical personnel can not only macroscopic hollow spray nozzle near field structure ( such as spray cone angle , the distance across the Sauter mean diameter , and the like ) were analyzed , but can also be observed in the hollow interior of the nozzle cavitation process disturbances jet liquid core surface area , even within the structure of the jet liquid core area . This helps IT personnel to some extent related to delve into the hollow interior of the nozzle nozzle cavitation , turbulence and jet atomization process. Fath , who use two-dimensional observation based on Mie scattering technique diesel hollow jet nozzle near-field structure were investigated . Their experiments observed in the vicinity of the hollow nozzle exit undisturbed liquid core (intact core) and tuck dense phase region exists in both the cavitation bubbles and cavitation bubbles appear in points