Abstract:During the process of pulverizing tough and tensile material through high pressure jet method, inefficiency of energy applications is always a prominent problem. Cavitation involved in high pressure jet operation has not been properly planned, effectively controlled and efficiently used. Short jet collision nozzle which is considered as a new type nozzle in order to promote cavitation effect and enhance collision energy density was investigated. And hydrodynamic cavitation mechanism occurred in short jet collision nozzle was also discussed. The key structure parameter of this nozzle was configured according to the results of computational fluid dynamics simulation. The radial and annular grooves were symmetrically manufactured on the nozzle surface by laser corrosion. Then superfine pulverizing experiments based on short jet collision nozzle were presented. The degree of hydrodynamic cavitation and the superfine effect of microcrystalline cellulose was tested through·OH level and scanning electron microscope. The experimental results showed that output rate of ·OH was increased by 41% and invalid kinetic energy was cut by 60%~80% compared with direct-hole nozzle. The micro fibril about 15nm long can be separated from fiber bundle of microcrystalline cellulose. Impact energy produced by bubble collision in this new type nozzle was promoted obviously. So efficient pulverization can be reached through the application of the short jet collision nozzle which can be perfectly used for superfine pulverizing tough and tensile biomaterials.