Numerical Simulation And Structure Optimization Of Double-layer Efficient Mixer

Mixer is one of the most pivotal equipments in the feed industry. Though there have been many experiments and academic researches about mixers at present, the theories and design methods are not so perfect. The combination of experiments and Computational Fluid Dynamics (CFD for short) provides a new effective method to research the flow field and its characteristics in the mixing equipments lately. Especially the CFD technology will produce a momentous influence on the design and developing of mixing equipments in the future. The three-dimensional flow field and the mixing characteristics of the double-layer effective mixer were numerical simulated with FLUENT at first. Detailed information and movement regulation of flow and mixing in the mixer were acquired from the simulation, which provided a credible proof for the selection and design of horizontal mixers in feed industry.The mixture model was adopted as the multiphase flow model. The RNG k -εturbulent model and multi-reference frame were also adopted in the simulation. The main studies are as follows:(1)An appropriate numerical model of the mixer was set up. To check the correctness of the adopted models, the result from the experiment of an existent thesis and the simulation were compared together.(2)The three-dimensional flow field was analyzed in detail, including the flow velocity field, the flow field distribution and the turbulent kinetic energy. The state of the whole flow was described.(3)A tracer was appended into the flow field, and its movement with respect to time was inspected. The simulation result indicated the process of mixing was determined to the state of the flow inside the mixer, and the most drastic mixing region lied on the extremum of the speed and the turbulent kinetic energy.(4)Mixing characteristics under different fullness-rate, blade angle and shape, and rotate velocity were simulated. The result indicated that changing the blade angle and the shape of the lesser blades would have great influences on the mixing effects. With the increase of rotate velocity, the mixing time was shortened, and the energy dissipation was growing. The mixing quality obviously decreased when the rotate velocity increased.