基于CFD-DEM的斜面平台对下降管内混合颗粒流动的影响  

Impact of inclined platforms on mixed marticle flow in down-tube based on CFD-DEM

作　　者：孙雪峰[1] 张德俐[1] 刘浩 高豪磊 马瑞 王芳[1] 金德禄 易维明[1] SUN Xuefeng;ZHANG Deli;LIU Hao;GAO Haolei;MA Rui;WANG Fang;JIN Delu;YI Weiming(College of Agricultural Engineering and Food Science,Shandong University of Technology,Zibo 255000,China;Shandong Luxi Dasheng Environmental protection Technology Co.,Ltd,Weifang 261000,China)

机构地区：[1]山东理工大学农业工程与食品科学学院,淄博255000 [2]山东禄禧大盛环保科技有限公司,潍坊261000

出　　处：《农业工程学报》2025年第5期240-249,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(52130610)。

摘　　要：为改善生物质热解过程中混合颗粒在下降管热解反应器内部流动时生物质颗粒扰动较小、混合不充分的问题,该研究探讨了管内斜面平台对陶瓷球和生物质颗粒流动的影响。以斜面平台的位置、倾斜角度和高度为试验因素,以生物质颗粒管内离散度为评判标准,通过计算流体力学与离散元法(computational fluid dynamics-discrete element method,CFD-DEM)耦合仿真对混合颗粒流动过程进行模拟,并利用粒子图像测速技术进行了验证。结果表明,斜面平台高度对生物质颗粒离散度影响最大,其次为位置和角度,最佳工作参数为斜面平台底部距下降管拐角处245 mm,高度为27 mm,角度为149°,相较于无斜面平台工况,生物质颗粒离散度提高了50.24%,进而提升了混合颗粒的混合程度。斜面平台的引入使得下降管内生物质颗粒和陶瓷球的轴向平均速度分别降低了14.38%和11.43%,平均停留时间分别升高了20.00%和5.75%,改变了无斜面平台时混合颗粒的向心流动特性,表现为抛物线形流动特性,打破了上疏下密的分布状态,使混合颗粒偏析降低,混合更为均匀。该研究结果能够为下降管式生物质热解反应器的设计与优化提供一定支持,有利于生物质快速热解技术的发展。Biomass particles can often be confined to the insufficient disturbance and mixing flow within the down-tube pyrolysis reactor.In this study,a systematic investigation was implemented to explore the influence of an inclined platform inside the down-tube on the flow behavior of ceramic balls and biomass particles.The particle mixing was also analyzed using experimental and simulation.The parameters of the inclined platform were treated as the experimental variables,including the position,tilt angle,and height.While the degree of particle dispersion was taken as the evaluation criterion.The particle flow was then simulated using computational fluid dynamics(CFD)coupled with the discrete element method(DEM).particle image velocimetry(PIV)was employed to verify the simulation.The results indicate that the height of the inclined platform shared the most significant effect on the dispersion degree of the particles,followed by the platform’s position and tilt angle.The optimal working parameters were determined after optimization,where the bottom of the inclined platform was positioned 245 mm from the corner of the down-tube,with a height of 27 mm and a tilt angle of 149°.The degree of particle dispersion increased by 50.24%under these optimal conditions,indicating the better homogeneity of the particle mixture.The inclined platform was introduced to significantly enhance the flow characteristics of the particles.Furthermore,the axial average velocities of the biomass particles and ceramic balls decreased by 14.38%and 11.43%,respectively,compared with the conditions without the inclined platform.Concurrently,the average residence time of the particles increased by 20.00%and 5.75%for the biomass particles and ceramic balls,respectively.As such,the inclined platform effectively extended the residence time of the particles within the down tube.Thus,the pyrolysis reactions were enhanced for the high efficiency of the reactor.Moreover,the inclined platform also altered the flow characteristics of the particles.In the abse

关 键 词：生物质 下降管 计算机仿真 CFD-DEM 气固两相流 

分 类 号：TK6[动力工程及工程热物理—生物能]