Single-phase flow patterns generated by axial impeller are investigated by 3D Particle Dynamic Analyzer. Mean flow and turbulence intensities are measured for the impeller zone and the bulk regions. The effect of D/T ...Single-phase flow patterns generated by axial impeller are investigated by 3D Particle Dynamic Analyzer. Mean flow and turbulence intensities are measured for the impeller zone and the bulk regions. The effect of D/T and blade tip angle on flow pattern is studied as well. The measured results show that the flow in impeller zone oscillates periodically at the frequency of blade sweep. The flow patterns generated by different ratios of impeller diameter to tank diameter impeller are approximately the same below impellers,but a small second recirculation loop is formed in the upper part of vessel at the ratio of impeller diameter to tank diameter D/T=0.35.展开更多
The mean and r.m.s velocities of solid-liquid flow system were measured by Particle Dynamic Analyzer in a fully baffled tank agitated by axial impellers.The effect of particle volumetric concentration was investigated...The mean and r.m.s velocities of solid-liquid flow system were measured by Particle Dynamic Analyzer in a fully baffled tank agitated by axial impellers.The effect of particle volumetric concentration was investigated as well.The results showed that the velocity profiles for two-phase flow were similar with those of the single-phase flow in the impeller region.The axial velocities for two-phase flow were higher than corresponding velocities of single-phase,and the maximum relative velocity occurred at the blade tip with 0.03 U tip in value.The turbulence levels were in general lower,about 50% reduction,than those of single-phase flow in the impeller region.Tangential velocities of two-phase flow decreased with increasing particle concentration while the axial velocities remained the same.Due to the presence of the particles,the discharge jet width became narrow.展开更多
首先探究了融合式翼梢小翼倾斜角、高度以及安装角对民用运输机气动特性的影响。然后基于多区域自由变形(FFD,free form deformation)技术、拉丁超立方取样方法(LHS,latin hypercube sampling)、Kriging代理模型以及改进的粒子群算法构...首先探究了融合式翼梢小翼倾斜角、高度以及安装角对民用运输机气动特性的影响。然后基于多区域自由变形(FFD,free form deformation)技术、拉丁超立方取样方法(LHS,latin hypercube sampling)、Kriging代理模型以及改进的粒子群算法构建优化设计系统,对融合式翼梢小翼应用优化系统,通过对FFD控制体框架的合理布置,实现了多个控制框架对融合式翼梢小翼的自由变形参数化设计。优化设计结果表明,设计后的融合式翼梢小翼较原始构型减阻效果有明显改善。并通过与"翼尖延伸"、"涡扩散器"和"双叉弯刀"等3种翼尖装置进行调参对比分析,得出一些对翼尖装置设计具有参考价值的结论。展开更多
文摘Single-phase flow patterns generated by axial impeller are investigated by 3D Particle Dynamic Analyzer. Mean flow and turbulence intensities are measured for the impeller zone and the bulk regions. The effect of D/T and blade tip angle on flow pattern is studied as well. The measured results show that the flow in impeller zone oscillates periodically at the frequency of blade sweep. The flow patterns generated by different ratios of impeller diameter to tank diameter impeller are approximately the same below impellers,but a small second recirculation loop is formed in the upper part of vessel at the ratio of impeller diameter to tank diameter D/T=0.35.
文摘The mean and r.m.s velocities of solid-liquid flow system were measured by Particle Dynamic Analyzer in a fully baffled tank agitated by axial impellers.The effect of particle volumetric concentration was investigated as well.The results showed that the velocity profiles for two-phase flow were similar with those of the single-phase flow in the impeller region.The axial velocities for two-phase flow were higher than corresponding velocities of single-phase,and the maximum relative velocity occurred at the blade tip with 0.03 U tip in value.The turbulence levels were in general lower,about 50% reduction,than those of single-phase flow in the impeller region.Tangential velocities of two-phase flow decreased with increasing particle concentration while the axial velocities remained the same.Due to the presence of the particles,the discharge jet width became narrow.
文摘首先探究了融合式翼梢小翼倾斜角、高度以及安装角对民用运输机气动特性的影响。然后基于多区域自由变形(FFD,free form deformation)技术、拉丁超立方取样方法(LHS,latin hypercube sampling)、Kriging代理模型以及改进的粒子群算法构建优化设计系统,对融合式翼梢小翼应用优化系统,通过对FFD控制体框架的合理布置,实现了多个控制框架对融合式翼梢小翼的自由变形参数化设计。优化设计结果表明,设计后的融合式翼梢小翼较原始构型减阻效果有明显改善。并通过与"翼尖延伸"、"涡扩散器"和"双叉弯刀"等3种翼尖装置进行调参对比分析,得出一些对翼尖装置设计具有参考价值的结论。
