水平管加压密相煤粉气力输送沙丘流的数值模拟  

Numerical Simulation on Dune Flow in Pressurized Dense Phase Pneumatic Conveying of Pulverized Coal in Horizontal Pipe

作　　者：蒲文灏[1,2] 赵长遂[2] 

机构地区：[1]南京航空航天大学能源与动力学院,南京210016 [2]东南大学能源与环境学院,南京210096

出　　处：《动力工程学报》2011年第2期120-126,共7页Journal of Chinese Society of Power Engineering

基　　金：国家重点基础研究发展规划基金资助项目(2004CB217702)

摘　　要：对Johnson等提出的摩擦正应力模型和Syamlal等提出的摩擦剪切黏度模型进行了修正,并将其与颗粒动理学理论相结合,建立了可以描述加压密相气力输送的气固湍流流动状况的三维多相流模型.该模型充分考虑了颗粒间碰撞和摩擦力作用,以及气相和颗粒团湍流脉动之间的相互作用.采用该模型对加压密相气力输送水平管沙丘流流动特性进行了三维数值模拟,并预测了单个沙丘和连续沙丘的形成及运动状况.结果表明:随着表观气速的增加,煤粉颗粒浓度减小,压降梯度呈现先减小后增大的趋势;在横截面上,煤粉颗粒分布呈现上窄下宽的趋势,且煤粉颗粒在管道底部沉积,并呈现月牙形状.模拟结果与试验结果吻合较好.Modifications were made for the frictional normal stresses model proposed by Johnson et al.and the frictional shear viscosity model proposed by Syamlal et al.Combining the modified model with the kinetic theory for granular flow,a 3-D multi-phase flow model was built up for gas-solid turbulent flow in pressurized dense phase pneumatic conveying.The model sufficiently took account of the collision and friction action among particles,and the interaction among gas phase and turbulent fluctuation of particles.The model was used to carry out the 3-D numerical simulation for the dune flow characteristics in pressurized dense phase pneumatic conveying in a horizontal pipe.The formation and motion process of the single dune and the continuous dunes were predicted.Results show that with the increase of apparent gas velocity,the concentration of pulverized coal decreases,and the pressure drop gradient decreases at first and then increases.On the cross section,the distribution of pulverized coal appears to be narrow on the upper part and broad on the lower part.Besides,there are coal particles deposited on the bottom of the pipe to form the dune.The simulated results agree well with the test results.

关 键 词：水平管 气力输送 密相 颗粒动理学 摩擦应力 沙丘流 数值模拟 

分 类 号：TQ051.23[化学工程]