Study On New Type Of Nozzle For Superfine Particles Preparation Using Supercritical Fluid Technology

Preparation of superfine particles using supercritical fluid (SCF) technology, effectively overcome the shortcomings of traditional preparation methods, has broad application prospects and research value. The nozzle is the core component of preparation device. The research of new nozzle is a key problem in the field of SCF precipitation.On the basis of the cone nozzle, The author propose a new nozzle which annular is formed by a sphere and a hole greatly increase the nozzle gap uniformity. Though assemble different components, we can get single passage nozzle, multi-passages with different blend modes nozzles which apply for different processes. The new nozzle's annular can be adjusted outside the precipitator.We optimize the structural parameters and process paremeters of single passage nozzle. We assume fluid is pure SCF, smooth surface of the nozzle, fluid flow is a steady-state process. We select the density ratio which before expansion to after expansion, turbulence intensity in flow field and the distance from jet junction position to nozzle exit as the evaluation index, definite the method of fuzzy marking. After establish the physical model,based on the real gas model. We simulate the flow field inside the nozzle to optimize the structural parameters and process parameters using Fluent software.We optimize the structural parameters and process paremeters of dual passage nozzle.We assume the process of fluid flow is steady, ignoring the impact of solute flow field, regardless of the surface roughness of the nozzle. We select solvent volume fraction and turbulence intensity of flow field as the evaluation index, definite the method of fuzzy marking.After establish the physical model,mesh, set boundary conditions,we simulate the nozzle flow to optimize the structure parameters and process parameters by multiphase flow model using Fluent software.