摘要
为了明确水平转竖直弯管中粗颗粒的输送特性,在实验验证的基础上,利用计算流体力学与离散元(Computational Fluid Dynamics and Discrete Elements,CFD-DEM)耦合数值模拟方法对直径2.5 mm、高3.3 mm粗颗粒在水平转竖直弯管中的输送流型、速度、质量流量和气相压力变化进行了研究。研究表明:在起送阶段,弯管料栓具有蓄能作用,难以一次过弯的颗粒会在弯管中自发组成形态稳定的料栓,待蓄能完成后继续过弯运动;沙丘流的输送速度小、平均质量流量高,束状流的输送速度大、平均质量流量低。在稳定输送阶段,固相流型、速度、质量流量波动相对稳定,弯管段的压降和颗粒平均速度在前后半段表现出明显差异;前半段压降小、等压线波动大、颗粒平均速度快;后半段压降大、等压线波动小、颗粒平均速度慢;水平管段颗粒流型为稳定分层流,弯管段前半段颗粒流型为束装颗粒流、后半段为颗粒堆积分层流,垂直管段颗粒流型随管道延伸在向悬浮流发展。
In order to reveal the transport characteristics of coarse particles in horizontal to vertical bends,this paper studied the transport flow pattern,velocity,mass flow rate and gas phase pressure variation of 2.5 mm diameter and 3.3 mm high coarse particles in horizontal to vertical bends using numerical simulation methods coupled with Computational Fluid Dynamics and Discrete Elements(CFD-DEM)on the basis of experimental verification.The simulate result show that the slug has an energy storage effect in the start-up stage,and the particles that are difficult to pass through the bend at once will form a stable slug in the bend spontaneously and continue to pass through the bend after the energy storage is completed;the conveying velocity of the dune flow is small and the average mass flow rate is high,while the conveying velocity of the rope flow is large and the average mass flow rate is low.In the stable conveying stage,the solid phase flow pattern,velocity and mass flow rate fluctuations are relatively stable,and the pressure drop and particle average velocity of the bend section show obvious differences in the first and second half,with small pressure drop,large isobaric fluctuations and fast particle average velocity in the first half and large pressure drop,small isobaric fluctuations and slow particle average velocity in the second half;the particle flow pattern of the horizontal pipe section is the stable stratified flow,and the particle flow pattern of the first half of the bend section is the rope flow and the second half is the stratified flow of particle packing,and the particle flow pattern in the vertical section is developing into the suspended flow with the extension of the pipe.
作者
巴涵
周甲伟
郭小乐
李冰
刘晓辉
BA Han;ZHOU Jia-wei;GUO Xiao-le;LI Bing;LIU Xiao-hui(School of Mechanical Engineering,North China University of Water Resources and Electric Power,Zhengzhou,Henan 450045;School of Construction Machinery,Chang'an University,Xi'an,Shaanxi 710064)
出处
《液压与气动》
北大核心
2023年第3期43-50,共8页
Chinese Hydraulics & Pneumatics
基金
国家自然科学基金(51805166)
河南省重大科技专项(201110210300)
河南省科技攻关项目(222102320084)
河南省高校科技创新团队支持计划(22IRTSTHN018)。
关键词
弯管
粗颗粒
气力输送
CFD-DEM数值模拟
气固两相流
bends
coarse particles
pneumatic conveying
CFD-DEM numerical simulation
gas-solid two-phase flow
