The particle mixing was studied in a cylindrical stirred tank with elliptical dished bottom by experiments and simulations.The impeller types used were double helical ribbon(HR) + bottom HR,pitched blade ribbon + bott...The particle mixing was studied in a cylindrical stirred tank with elliptical dished bottom by experiments and simulations.The impeller types used were double helical ribbon(HR) + bottom HR,pitched blade ribbon + bottom HR,inner and outer HR + bottom HR,and pitched blade ribbon + Pfaudler + bottom HR labeled as impellers Ⅰ to Ⅳ,respectively.The quantitative correlations among the rotational speed,fill level and power consumption for impeller Ⅰ and impeller Ⅱ were obtained by experiments to validate the discrete element method(DEM) simulations.The particle mixing at different operating conditions was simulated via DEM simulations to calculate the mixing index using the Lacey method,which is a statistical method to provide a mathematical understanding of the mixing state in a binary mixture.The simulation results reveal that as the rotational speed increases,the final mixing index increases,and as the fill level increases,the final mixing index decreases.At the same operating conditions,impeller Ⅲ is the optimal combination,which provides the highest mixing index at the same revolutions.展开更多
The US and EU markets are the main destinations of Chinese forest products.Through analyzing the similarities and differences between the US Lacey Act Amendment and the EU Timber Regulation,the paper focused on how to...The US and EU markets are the main destinations of Chinese forest products.Through analyzing the similarities and differences between the US Lacey Act Amendment and the EU Timber Regulation,the paper focused on how to realize better compatibility and practicality of Chinese timber legality verification scheme in terms of verification standard setting,verification procedures,pilot work of timber legality verification scheme,capacity-building trainings and studies on key problems.展开更多
为了进一步研究水平放置的回转类容器内物料的混合行为。首先采用CAD软件进行建立模型,然后利用离散单元法(discrete element method, DEM)对横截面积相同、内部结构不同的回转容器进行数值模拟和结果分析,以Lacey指数评价法作为物料混...为了进一步研究水平放置的回转类容器内物料的混合行为。首先采用CAD软件进行建立模型,然后利用离散单元法(discrete element method, DEM)对横截面积相同、内部结构不同的回转容器进行数值模拟和结果分析,以Lacey指数评价法作为物料混合效果的判断依据,对不同工况条件进行分析,旨在研究不同内部结构的滚筒对物料混合行为的影响。研究结果表明:滚筒内部结构的不同对物料混合行为有着很大影响。滚筒壁面设置横向挡板、斜向挡板、人字形挡板均可以提高滚筒的混合效率,其中人字形挡板在反向旋转工况条件下混合效果较其他几组更加优越。展开更多
文摘The particle mixing was studied in a cylindrical stirred tank with elliptical dished bottom by experiments and simulations.The impeller types used were double helical ribbon(HR) + bottom HR,pitched blade ribbon + bottom HR,inner and outer HR + bottom HR,and pitched blade ribbon + Pfaudler + bottom HR labeled as impellers Ⅰ to Ⅳ,respectively.The quantitative correlations among the rotational speed,fill level and power consumption for impeller Ⅰ and impeller Ⅱ were obtained by experiments to validate the discrete element method(DEM) simulations.The particle mixing at different operating conditions was simulated via DEM simulations to calculate the mixing index using the Lacey method,which is a statistical method to provide a mathematical understanding of the mixing state in a binary mixture.The simulation results reveal that as the rotational speed increases,the final mixing index increases,and as the fill level increases,the final mixing index decreases.At the same operating conditions,impeller Ⅲ is the optimal combination,which provides the highest mixing index at the same revolutions.
基金Supported by WWF Project"Support Chinese Government to Develop Timber Legality Verification Scheme"
文摘The US and EU markets are the main destinations of Chinese forest products.Through analyzing the similarities and differences between the US Lacey Act Amendment and the EU Timber Regulation,the paper focused on how to realize better compatibility and practicality of Chinese timber legality verification scheme in terms of verification standard setting,verification procedures,pilot work of timber legality verification scheme,capacity-building trainings and studies on key problems.
文摘为了进一步研究水平放置的回转类容器内物料的混合行为。首先采用CAD软件进行建立模型,然后利用离散单元法(discrete element method, DEM)对横截面积相同、内部结构不同的回转容器进行数值模拟和结果分析,以Lacey指数评价法作为物料混合效果的判断依据,对不同工况条件进行分析,旨在研究不同内部结构的滚筒对物料混合行为的影响。研究结果表明:滚筒内部结构的不同对物料混合行为有着很大影响。滚筒壁面设置横向挡板、斜向挡板、人字形挡板均可以提高滚筒的混合效率,其中人字形挡板在反向旋转工况条件下混合效果较其他几组更加优越。
