Study Of The Mixing Procedure Of Nanomaterials And Its Enhancement By Ultrasound

In the process of development of a mixer, numerical simulation method is employed for the study of the flow field and its enhanced features in the high-speed stirring equipment. A basis for the development and improvement of mixing equipment is provided.On the basis of explore the dispersion theoretical knowledge, a brief introduction of computational fluid dynamics method and flow field numerical model is given. Ultrasonic dispersion mechanism and acoustic streaming driving force equation is derived, and a brief introduction to the numerical simulation of acoustic cavitations is given. Multiple reference frame (MRF) is used to numerically simulate the flow field in nano-particles homogenized device under steady-state. Confirms the mechanical stirring shear force and local impact is generated the main reason for dispersed. Studies have shown that the rotor and stator is the important dispersed area. There are two cycles of macro and micro flow in the flow field. Improving the speed can improve the efficiency of decentralized. Under the action of ultrasonic vibrations, as well as the joint action of ultrasonic and high-speed stirring, the flow field in the homogenate device is numerically simulation. It shows that dispersion effect under the sound stream driving force only is not obvious and the further numerical simulation of the ultrasonic cavitations is needed. Also the simulation under the unsteady-state is did to analog of the homogenates device internal flow field. Concentration and pressure changes of the monitoring points were analyzed. The analysis of the relations of the mixing time and stirring speed of the flow field are focused and the curve of a stream exchange slurry concentration vs. time obtained. It shows that the increase of the stirring speed can reduced the mixing time; thereby the stirring efficiency is improved.In this study, we have obtained the flow characteristics of the flow field in the mixer during the preparation of nano-materials and the flow characteristics when the fluid mixing under shear agitation with an ultrasonic mixer. The study has provided some guidance for the designation of the mixing device.