提出了一种新型的拟循环边界条件,并采用计算流体力学(computational fluid dynamics,CFD)中VOF(volume of fluid)多相流模型对液相在两相邻规整填料特征单元上的分布进行三维仿真模拟,数值模拟结果与已有经验公式具有较好的吻合性。从...提出了一种新型的拟循环边界条件,并采用计算流体力学(computational fluid dynamics,CFD)中VOF(volume of fluid)多相流模型对液相在两相邻规整填料特征单元上的分布进行三维仿真模拟,数值模拟结果与已有经验公式具有较好的吻合性。从介尺度的角度出发,系统地研究了规整填料的宏观结构和微观结构对液相在规整填料片上分布的影响。结果表明:规整填料的波纹倾角和表面微观结构对液相特别是低表面张力物系在规整填料内的流动形态有很大的影响,而比表面积对液相在规整填料内的流型几乎无影响。相同液相流率下,液相在高比表面积、填料表面有波纹的Y型规整填料片上的分布较好,具有较好的流体力学性能。展开更多
Layered Double Hydroxides MgFe-LDH and MgAl-LDH have been prepared by th e method involving separate nucleation and ageing steps. The structure analyses for these two materials show that the values of the parameters b...Layered Double Hydroxides MgFe-LDH and MgAl-LDH have been prepared by th e method involving separate nucleation and ageing steps. The structure analyses for these two materials show that the values of the parameters both a and c of M gAl-LDH are smaller than that of MgFe-LDH though their structures are simila r, and MgAl-LDH with higher crystallinity is more easily formed than MgFe-LD H in the same preparing conditions. The IR analyses manifest that the structures of layer sheets and the orderings of the anions in the interlayer regions of Mg Al-LDH are more regular than that of MgFe-LDH. The temperature programmed XR D analyses reveal that the diffraction peak of 003 reflections for MgAl-LDH co uld be seen after calcining at 300℃, while this peak for MgFe-LDH disappears after calcining at 200℃. Together with the TG-DTA analysis it can be conclu ded that the thermal stability of MgAl-LDH is obviously higher than that of Mg Fe-LDH.展开更多
文摘提出了一种新型的拟循环边界条件,并采用计算流体力学(computational fluid dynamics,CFD)中VOF(volume of fluid)多相流模型对液相在两相邻规整填料特征单元上的分布进行三维仿真模拟,数值模拟结果与已有经验公式具有较好的吻合性。从介尺度的角度出发,系统地研究了规整填料的宏观结构和微观结构对液相在规整填料片上分布的影响。结果表明:规整填料的波纹倾角和表面微观结构对液相特别是低表面张力物系在规整填料内的流动形态有很大的影响,而比表面积对液相在规整填料内的流型几乎无影响。相同液相流率下,液相在高比表面积、填料表面有波纹的Y型规整填料片上的分布较好,具有较好的流体力学性能。
文摘Layered Double Hydroxides MgFe-LDH and MgAl-LDH have been prepared by th e method involving separate nucleation and ageing steps. The structure analyses for these two materials show that the values of the parameters both a and c of M gAl-LDH are smaller than that of MgFe-LDH though their structures are simila r, and MgAl-LDH with higher crystallinity is more easily formed than MgFe-LD H in the same preparing conditions. The IR analyses manifest that the structures of layer sheets and the orderings of the anions in the interlayer regions of Mg Al-LDH are more regular than that of MgFe-LDH. The temperature programmed XR D analyses reveal that the diffraction peak of 003 reflections for MgAl-LDH co uld be seen after calcining at 300℃, while this peak for MgFe-LDH disappears after calcining at 200℃. Together with the TG-DTA analysis it can be conclu ded that the thermal stability of MgAl-LDH is obviously higher than that of Mg Fe-LDH.
