Baffles with shape of ＂-＂ （single baffle）, ＂＋＂ （cross-baffles with four arms） and （baffles with 6 arms） are used to enhance the mixing of particles in a rotating drum mixer. A micro-dynamics study of mixing...Baffles with shape of ＂-＂ （single baffle）, ＂＋＂ （cross-baffles with four arms） and （baffles with 6 arms） are used to enhance the mixing of particles in a rotating drum mixer. A micro-dynamics study of mixing and segregation ofa bi-disperse system of two particle sizes in the rotating drum with these three kinds of baffles is carried out using the discrete element method （DEM）. The effect of the baffles on mixing, and the mechanisms of mixing enhancement by the baffles are discussed and analyzed. Simulation results show that in an unbaffled drum mixer, particle convection, particle diffusion, and size segregation of hi- disperse particles, all play important roles in the mixing process; whereas size segregation will be largely restrained when the drum mixer has a baffle, regardless of its shape, and the degree of mixing is higher than that in an unbaffled drum mixer. The different mixing characteristics for ＂-＂ shaped baffle, ＂＋＂ baffle, and baffle are revealed by the simulation results. For ＂＋＂ or style baffles, there is an optimal size of baffles for the mixing of particles, and the ootimal mixing efficiency is higher than that for ＂-＂ baffle.展开更多
The objective of this study is to examine several optimization problems in the batch mixing of segregating particulate solids that can be set up and solved using Markov chain models. To improve the adequacy of such mo...The objective of this study is to examine several optimization problems in the batch mixing of segregating particulate solids that can be set up and solved using Markov chain models. To improve the adequacy of such models and exclude some physical contradictions that arise in the linear form, a non-linear Markov chain model for the mixing of segregating components is proposed. Optimal solutions are obtained by controlling the particle flow outside the mixing operating volume while the components are being loaded, modifying particle circulation inside the mixing zone during the process, and by structuring the load in the mixing zone. Solutions are found that not only reduce the negative influence of segregation, but also exclude it altogether. The gain resulting from optimization grows with the rate of segregation. The optimal solutions presented here can be used to improve the design of mixers.展开更多
本文应用流化床内固体浓度差产生的浮力与具有不同物性颗粒的扩散之间的动态平衡原理,研究铁珠与黄砂系统在内径为38mm 移动流化床内的混合与分级,包括流化速度和颗粒移动速度对分级的影响。采用的分级指数定义为:N=S~*/Z·X_v=1-in...本文应用流化床内固体浓度差产生的浮力与具有不同物性颗粒的扩散之间的动态平衡原理,研究铁珠与黄砂系统在内径为38mm 移动流化床内的混合与分级,包括流化速度和颗粒移动速度对分级的影响。采用的分级指数定义为:N=S~*/Z·X_v=1-integral from 0 to Z XvdZ/Z·integral from 0 to 1 XvdZ分级指数的范围为0<N<1;完全分级时 N=1,完全混合时 N=0。展开更多
基金supported by the Science Foundation of Chinese Universitythe Zhejiang Provincial Natural Science Foundation of China (Grant No. Y1100636)
文摘Baffles with shape of ＂-＂ （single baffle）, ＂＋＂ （cross-baffles with four arms） and （baffles with 6 arms） are used to enhance the mixing of particles in a rotating drum mixer. A micro-dynamics study of mixing and segregation ofa bi-disperse system of two particle sizes in the rotating drum with these three kinds of baffles is carried out using the discrete element method （DEM）. The effect of the baffles on mixing, and the mechanisms of mixing enhancement by the baffles are discussed and analyzed. Simulation results show that in an unbaffled drum mixer, particle convection, particle diffusion, and size segregation of hi- disperse particles, all play important roles in the mixing process; whereas size segregation will be largely restrained when the drum mixer has a baffle, regardless of its shape, and the degree of mixing is higher than that in an unbaffled drum mixer. The different mixing characteristics for ＂-＂ shaped baffle, ＂＋＂ baffle, and baffle are revealed by the simulation results. For ＂＋＂ or style baffles, there is an optimal size of baffles for the mixing of particles, and the ootimal mixing efficiency is higher than that for ＂-＂ baffle.
文摘The objective of this study is to examine several optimization problems in the batch mixing of segregating particulate solids that can be set up and solved using Markov chain models. To improve the adequacy of such models and exclude some physical contradictions that arise in the linear form, a non-linear Markov chain model for the mixing of segregating components is proposed. Optimal solutions are obtained by controlling the particle flow outside the mixing operating volume while the components are being loaded, modifying particle circulation inside the mixing zone during the process, and by structuring the load in the mixing zone. Solutions are found that not only reduce the negative influence of segregation, but also exclude it altogether. The gain resulting from optimization grows with the rate of segregation. The optimal solutions presented here can be used to improve the design of mixers.
文摘本文应用流化床内固体浓度差产生的浮力与具有不同物性颗粒的扩散之间的动态平衡原理,研究铁珠与黄砂系统在内径为38mm 移动流化床内的混合与分级,包括流化速度和颗粒移动速度对分级的影响。采用的分级指数定义为:N=S~*/Z·X_v=1-integral from 0 to Z XvdZ/Z·integral from 0 to 1 XvdZ分级指数的范围为0<N<1;完全分级时 N=1,完全混合时 N=0。
