The Numerical Simulation And Optimization Of A Horizontal Screw Feed Mixer

The horizontal ribbon mixer is widely used in feed mixing process, and the mixingefficiency depends on the level of the internal flow characteristics and the mixingcharacteristics of the device. With the improvement and development of computerperformance computational fluid dynamics （CFD） technology, people used the test andnumerical simulation studying a lot of work in the flow field inside the feed mixer which wasfound in most of the equipment Turbulent flow field. However, the current study focused onthe paddle mixer, which the ribbon blender less. In this paper, the commercial CFD softwareFLUENT was used to simulate the flow field and mixing characteristics of a horizontal ribbonmixer, obtainied the movement of the flow field in the mixer, and the using parameters werealso optimized.It can provide a reliable basis for the feed industry in select and design of thehorizontal ribbon mixing machine.In this paper, a numerical model was established for the horizontal ribbon mixer study,gas-solid model used the mixture model,while turbulence model used the standardk model.The rotor processing method used the multiple reference frame （MRF）. Mainlysolved the following issues：（1） Establishing a numerical model. Established the three-dimensional model ofribbon rotor in CATIA, the body will be simplified as a O-type mixer, importing FLUENTGAMBIT pre-processing software to generate the actual flow field geometry and boundaryconditions in line with the finite element model.（2） Analysising the flow characteristics. By analyzing the flow field velocity,turbulent kinetic energy and material volume distribution, the result showed that themovement speed of the inside ribbon and outside ribbon were in the opposite direction.Theturbulence between the inner and outer ribbon increased promoting convective mixing whileoutside ribbon area speed faster than the inner to promote shear mixing.（3） Analysising the mixing characteristic.Tracers were added to simulate the tracerconcentration changing with mixing time. Since the movement pattern of the mixer, the concentration of each point of change of the tracer is uniform, with the same trend.When therotational speed40r/min,70%in filling ratio, the mixing time was70s. Refered to the relevantexperimental literature and compared the mixing characteristics with the simulation to verifythe numerical model.（4）Using parameter optimization. The material filling ratio and mixer rotor speed waschanged to analyse the mixing characteristics. The results showed little effect was caused onthe quality by the filling rate, but it had a great impact on the mixing energy; with theincreasing rotor speed, mixing time decreases, the energy consumption increased in turn,results showed that when the selected mixing Machine filling ratio reached70%, the optimalspeed was40r/min.