散状物料斜面出流下落过程流动特性研究
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摘要
利用DPM-CFD模型对斜面出流散状物料下落过程中气流速度的分布规律、颗粒的扩散和运动特性进行了研究.研究发现,随着下落高度的增加空气流速先增后减,且颗粒流周围有明显的涡流产生.颗粒流质量流量和初始速度增加均会导致空气速度的峰值及偏移位移增加.颗粒流质量流量对空气速度峰值的影响较大;而出流速度对空气速度峰值偏移位移的影响较大.同时,颗粒流质量流量和初始速度也使颗粒物浓度峰值的偏移位移有所增加,但增大质量流量会导致浓度峰值增加,而初始速度的增加则会减小浓度峰值.颗粒物的质量流量和初始速度对浓度峰值的影响程度相当,而颗粒流初始速度对峰值偏移位移的影响程度略大于质量流量.
The air velocity distributions,particle diffusion and movement characteristic of an inclined plane outflow particle stream are studied.The simulation results show that air velocity increases firstly and decreases then with the increasing of drop height,while vortex is produced around particle stream.Increased mass flow rate and particle stream initial velocity increased air velocity peak value and peak value displacement.The mass flow rate strongly influences air velocity peak value,while particle stream outflow velocity greatly influences peak value displacement.Besides,both mass flow rate and particle stream initial velocity lead to the increase of peak value displacement,while concentration peak value increases with mass flow rate increasing,and decreases with particle stream initial velocity increasing.The mass flow rate and particle stream initial velocity have the same effect on concentration peak value,though initial velocity influences slightly larger than mass flow on peak value displacement.
The air velocity distributions,particle diffusion and movement characteristic of an inclined plane outflow particle stream are studied.The simulation results show that air velocity increases firstly and decreases then with the increasing of drop height,while vortex is produced around particle stream.Increased mass flow rate and particle stream initial velocity increased air velocity peak value and peak value displacement.The mass flow rate strongly influences air velocity peak value,while particle stream outflow velocity greatly influences peak value displacement.Besides,both mass flow rate and particle stream initial velocity lead to the increase of peak value displacement,while concentration peak value increases with mass flow rate increasing,and decreases with particle stream initial velocity increasing.The mass flow rate and particle stream initial velocity have the same effect on concentration peak value,though initial velocity influences slightly larger than mass flow on peak value displacement.
引文
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[2]WYPYCH P,COOK D,COOPER P.Controlling dust emissions and explosion hazards in powder handling plants[J].Chem Eng Process,2005,44:323-326.
[3]LIU Z.Experimental investigation of dust amount from free falling particle stream affected by deflector curvature of dust suppression[J].Adv Mat Res,2014,864-867:1789-1792.
[4]HEMEON W C L.Plant and process ventilation[M].New York:The Industrial Press,1963.
[5]LI X,LI Q.Model for induced airflow velocity of falling materials in semi-closed transfer station based on similitude theory[J].Adv Powder Technol,2015,26:236-243.
[6]LIU Z.Air entrainment in free falling bulk materials[D].Wollongong:University of Wollongong,2001.
[7]ANSART R,DERYCK A,DODDS J A,M et al.Dust emission by powder handling:Comparison between numerical analysis and experimental results[J].Powder Technol,2009,190:274-281.
[8]WANG Y,REN X F.Experimental study of flow regimes and dust emission in a free falling particle stream[J].Powder Technol,2016,292:14-22.
[9]王怡,樊航,任晓芬.自由下落非均一粒径颗粒流的流场特性[J].西安建筑科技大学学报(自然科学版),2015(3):418-422.