Research On The Simulation&Application Of The Food Residue Biochemical Processor Mixing Flow Field Based On The CFD

At present, the food residue production in our country is a huge part of the urban living garbage. Traditional treatments are not suit to the food residue, so doing research on the biochemical processor is a new trend in this field. However, the existing design methods of the food residue biochemical processor are all based on the engineering experience, lack of guidance of theoretical research. Besides, different mixing structure, different material properties and other parameters can affect the processing speed, thereby increasing energy consumption. This issue is particularly serious in the large processing machine. Therefore, the mixing flow field of the processor is the research object in this paper by means of the mechanism of mixing and the computational fluid dynamics. The separated algorithm based on the pressure, the RNG turbulence model, the VOF model and the multiple reference frame method are adopted to simulate the flow field of the mixing model constructed in Fluent6.3.First of all, the flow model is constructed according to the original processor, and the velocity and the turbulent kinetic energy distribution are simulated by the Fluent; the shaft power is calculated by the simulation results, and the correctness of simulation results is verified by the empirical formula calculation.Secondly, nine simulation models are built with such different parameters as the shaft rotation speed, the viscosity of food residue and the blade installation angle. The influence of different parameters to the velocity and the turbulent kinetic energy is analyzed in this paper.Thirdly, orthogonal experiment with three factors and three levels is designed in SPSS. The shaft rotation speed, the viscosity of food residue and the blade installation angle are chosen to be the three factors, and the shaft power and the maximum turbulent kinetic energy are set as the test index. The primary and secondary of the factors and the best combination of them are obtained by range analysis.Finally, according to orthogonal test analysis, the original mixing structure is optimized and new simulation model is constructed to verify that the optimization of feasible and effective. The optimized scheme is used on the household food residue biochemical processor. The research results show that the maximum velocity appears near the blade tip region, and the maximum turbulent kinetic energy appears in the middle of the area between the stirring shaft; the primary factor affecting the shaft power is rotation speed and the primary factor influencing the mixing effect is the blade installation angle. Based on the optimal level group obtained from the orthogonal test, the mixing structure after optimization not only meets the basic requirements of mixing evenly, but also owns high efficiency and low energy consumption.