Elbows in pneumatic conveying systems are normally prone to the erosive effects of conveyed particles.There are a number of solutions available to reduce such damage.A widely used geometric alternative for replacing t...Elbows in pneumatic conveying systems are normally prone to the erosive effects of conveyed particles.There are a number of solutions available to reduce such damage.A widely used geometric alternative for replacing the 90°elbow and reducing erosive wear is the plugged tee.Another option,although less commonly used,is the vortex-chamber elbow.In both cases,the effective reduction in erosion brought about is unclear,as it strongly depends on the operating conditions.The present study assesses relative erosion among the plugged tee,vortex-chamber elbow,and standard elbow for a dilute gas-solid multiphase flow.A numerical model is employed to predict the penetration ratio and validated using experimental data for the plugged tee.Simulations are run for the standard and vortex-chamber elbows and plugged tee under the same conditions to compare the mechanics involved and the relative erosion reduction.The analysis uses variables relating to particle-wall interactions(impact angle,impact velocity,impact frequency)to illustrate the nature of the erosive process in each pipe fitting.In general,the geometric configurations of both the plugged tee and vortex-chamber elbow promote changes in particle dynamics that reduce the rate of erosion.On the basis of the relative erosion of the standard elbow,the plugged tee proves to be an interesting option in cases of a low mass loading,while the vortex-chamber elbow demonstrates its erosion reduction potential for higher mass loading conditions.Furthermore,the advantages and disadvantages of each fitting are highlighted.展开更多
为解决城市轨道交通管线复杂且生成管道3D模型仍依赖人机交互的问题,提出一种自动生成参数化BIM(building information modeling)管道连接件的方法。针对因绘图不规范而导致管道的起点和终点坐标无法唯一确定的问题,该方法基于直管中心...为解决城市轨道交通管线复杂且生成管道3D模型仍依赖人机交互的问题,提出一种自动生成参数化BIM(building information modeling)管道连接件的方法。针对因绘图不规范而导致管道的起点和终点坐标无法唯一确定的问题,该方法基于直管中心线坐标,通过空间向量运算自动判断两根、三根和四根管线间应添加的弯头、三通、四通等连接件类型,然后结合标准构件尺寸表计算管件形状和位置参数。此外,利用IFC(industry foundation classes)表达模型,使用C++语言实现模型的自动生成。经验证,该方法可显著提高管道模型生成效率和自动化程度。展开更多
文摘Elbows in pneumatic conveying systems are normally prone to the erosive effects of conveyed particles.There are a number of solutions available to reduce such damage.A widely used geometric alternative for replacing the 90°elbow and reducing erosive wear is the plugged tee.Another option,although less commonly used,is the vortex-chamber elbow.In both cases,the effective reduction in erosion brought about is unclear,as it strongly depends on the operating conditions.The present study assesses relative erosion among the plugged tee,vortex-chamber elbow,and standard elbow for a dilute gas-solid multiphase flow.A numerical model is employed to predict the penetration ratio and validated using experimental data for the plugged tee.Simulations are run for the standard and vortex-chamber elbows and plugged tee under the same conditions to compare the mechanics involved and the relative erosion reduction.The analysis uses variables relating to particle-wall interactions(impact angle,impact velocity,impact frequency)to illustrate the nature of the erosive process in each pipe fitting.In general,the geometric configurations of both the plugged tee and vortex-chamber elbow promote changes in particle dynamics that reduce the rate of erosion.On the basis of the relative erosion of the standard elbow,the plugged tee proves to be an interesting option in cases of a low mass loading,while the vortex-chamber elbow demonstrates its erosion reduction potential for higher mass loading conditions.Furthermore,the advantages and disadvantages of each fitting are highlighted.
文摘为解决城市轨道交通管线复杂且生成管道3D模型仍依赖人机交互的问题,提出一种自动生成参数化BIM(building information modeling)管道连接件的方法。针对因绘图不规范而导致管道的起点和终点坐标无法唯一确定的问题,该方法基于直管中心线坐标,通过空间向量运算自动判断两根、三根和四根管线间应添加的弯头、三通、四通等连接件类型,然后结合标准构件尺寸表计算管件形状和位置参数。此外,利用IFC(industry foundation classes)表达模型,使用C++语言实现模型的自动生成。经验证,该方法可显著提高管道模型生成效率和自动化程度。
