颗粒群在燃烧环境中的曳力研究  

Drag Force on Particle Group Under Combustion Condition

作　　者：屈思博 张纬 由长福[1,2] Qu Sibo;Zhang Wei;You Changfu(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;Shanxi Research Institute for Clean Energy,Tsinghua University,Taiyuan 030000,China)

机构地区：[1]清华大学能源与动力工程系,热科学与动力工程教育部重点实验室,北京100084 [2]清华大学山西清洁能源研究院,太原030000

出　　处：《燃烧科学与技术》2023年第6期624-634,共11页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51761125012);华能集团总部科技项目——基础能源科技研究专项资助项目(HNKJ20-H50).

摘　　要：对颗粒半径为100~500μm、体积分数为0.075~0.35的固定随机分布的颗粒群在303 K与1173K环境温度下的受力及相应的流场进行模拟.模拟工具为虚拟区域法.它采用统一形式的结构化网格描述颗粒与气体,并实现两相的相互作用,兼有较高的准确度与效率.相关结果显示,颗粒群在燃烧环境中形成的流场更稳定,这主要是由于气体在燃烧环境中的黏性更大,导致雷诺数更小.同时,颗粒群在燃烧环境中所受黏性力更大.在较低与较高的雷诺数下,颗粒群在燃烧环境中的曳力分别更大与更小.随着颗粒尺寸增大,颗粒群的燃烧强度与曳力均增大;随着颗粒体积分数增大,颗粒群的燃烧强度减小但是曳力增大.最后,本研究对于颗粒群的终端速度、曳力系数以及气-固动量交换系数提出了在燃烧环境中的修正.In this study,a set of gas-solid flow simulations with fixed randomly distributed particles was implemented.The particle radius was set as 100—500μm,the particle volume fraction was set as 0.075—0.35,and the temperature was set as 303 K and 1173K,representing the normal and combustion conditions,respectively.The fictitious domain method was adopted as the numerical tool,which uses a unified structured mesh to describe particle and gas and realizes two-phase interaction,with high accuracy and efficiency.Relevant results show that the flow field formed by particle group in the combustion environment is more stable,which is mainly due to the smaller particle Reynolds number resulting from larger gas viscosity.The viscous force of particle group is greater in the combustion environment.The drag force of particle group in the combustion environment is large at low Reynolds numbers and small at high Reynolds numbers.With the increase of particle size,both the combustion intensity and drag force of particle group increase;with the increase of particle volume fraction,the combustion intensity of particle group decreases but the drag force increases.Finally,the corrections of particle terminal velocity,drag force coefficient and gas-solid momentum exchange coefficient in the combustion environment were proposed.

关 键 词：多相流 煤燃烧 颗粒群 曳力 虚拟区域法 

分 类 号：TK11[动力工程及工程热物理—热能工程]