【摘 要】
：
In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart\'s group B as bed material.The simulations were performed using a homogeneous
【机 构】
：
Hamburg University of Technology,Institute of Solids Process Engineering and Particle Technology,Den
论文部分内容阅读
In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart\'s group B as bed material.The simulations were performed using a homogeneous drag model as well as a structure dependent drag model based on the energy minimization multi-scale method(EMMS).The results are compared with experimental data from literature as well as experiments.The simulations with the EMMS based drag model show a good agreement of the time-averaged axial solids concentration,circulation rate and riser pressure drop.Furthermore,a lower grid sensitivity is observed compared to the homogeneous drag model.In contrast to the conventional drag model a dense bottom zone is predicted by the EMMS based drag model.An overprediction of the solid concentration in the dense bottom zone is presumably due to an overprediction of the cluster diameter that is calculated using an empirical cluster diameter correlation.This shows the necessity for a new meso-scale cluster correlation for the simulation of Geldart B particles.Furthermore,the results of the time-averaged radial solids concentration differ from the expectations of a core-annulus flow indicating that a mesh refinement at the walls is necessary.Finally,the importance of using a realistic particle size distribution is identified.
其他文献
本文基于乡村振兴战略,围绕广州市从化区村镇水环境质量改造目标,调查分析从化区农村生活污水处理的现状,探析该区农村生活污水处理特征,为农村生活污水处理的工艺及管理模式的决策提供参考依据,以期使污水处理的民心工程发挥效益,呈现水清景美的村容村貌.
Particulate flows in a mixture of gas and liquid,i.e.gas-liquid-solid three-phase flows,are frequently encountered both in nature and industry.In such flows,complex interactions between multiple phases,i.e.particle-particle interactions,fluid-particle int
本文以项目管理理论为切入点,介绍建筑管理现状,从中得出管理模式在成本控制、激励机制以及信息化应用方面存在的问题,并从强化实施过程的成本控制、培育绩效激励意识和加强信息化建设方面,提出建筑工程项目管理优化措施,以加快建筑行业的高效发展.
本文围绕新时期园艺技术和园林景观的设计展开分析,园艺技术为园林景观的基础,园林景观的设计可以帮助园艺技术实现进一步的发展,对两者的发展趋势展开分析,能更好地推动当前城市建设发展.
管道直饮水设计需要考虑学校饮用水的特点,还应满足水处理技术的先进性和合理性.本文以实际案例对小学建筑直饮水系统设计要点进行了分析.
Gas-solid flows are ubiquitous in industrial systems.The coupled model of the discrete element method(DEM)and computational fluid dynamics(CFD)is one of the techniques for the simulation of the gas-solid flows.To enhance the applicability of the DEM-CFD m
本文从热水系统设计原理、集热器的比选、系统冷热水压力的平衡等方面结合工程案例,经计算确定系统各设备选型,初步估算系统能耗比电加热热水系统减少约87.5％,节能效果显著.
近几年,为持续推进环境友好型社会良好发展,国家对可持续战略规划内容进行了统筹部署与大力践行,其中海绵城市理念作为可持续发展理念的延伸表现,目前已经应用于城市规划设计中.为保障海绵城市理念在城市规划中发挥预期的功效,本文主要对海绵城市理念及其在城市规划中的创新策略问题进行研究与分析.
防雷接地系统设计作为建筑电气工程设计的重要组成部分,主要为了降低雷电对建筑物、人身安全及建筑内电气系统的影响,保障建筑物的正常运行.本文主要对建筑智能防雷系统设计中的要点问题进行了讨论,希望能给相关从业人员带来帮助.
本文运用电子行业和机加工行业的标准工时定额的计算方法,通过对铝合金门窗的工序分析,测定各工序作业单元的节拍,结合评比因数和作业宽放率,并运用数学建模进行数据处理,分析确定铝合金窗加工过程中的标准工时.