The objective of this study is analysis of heat-up process of wet woody particles on a backward acting grate including dynamics motion investigation by implementing XDEM （extended discrete element method） as a novel...The objective of this study is analysis of heat-up process of wet woody particles on a backward acting grate including dynamics motion investigation by implementing XDEM （extended discrete element method） as a novel approach. In this method, the particles are resolved as the discrete phase （individual elements） coupled via heat, mass and momentum transfer to the continuous gas phase. The temperature of particulates along the backward acting grate is investigated by evaluating effects of operating parameters such as bar amplitude and period. Furthermore, the bar motion has effects largely on the heat-up process of the packed bed on the backward acting grate which is considered here as well. In other words, motion of particles caused by bar motion influences the heat transfer of particles and totally the packed bed. In fact, the particles＇ heat-up is performed by a radiative heat flux facing the packed bed surface so that heat transfer of particles as radiation and conduction with surrounding particles is taken into account in addition to convection heat transfer between particles and surrounding gas phase.展开更多
Based on the analysis of heat transfer mechanics,physical and chemical change of pellet drying and preheating process in grate,the mathematical model is established and solved by three-diagonal matrix algorithm. With ...Based on the analysis of heat transfer mechanics,physical and chemical change of pellet drying and preheating process in grate,the mathematical model is established and solved by three-diagonal matrix algorithm. With Visual Basic 6.0 a simulation software is developed.The model is verified by measurements at a domestic pellet plant,and the temperature distribution of pellet bed is gained.Meanwhile,the influence of different operation parameters on the pellet thermal process is studied.The results can be taken as a basis of practical production control and the grate optimizing design.展开更多
文摘The objective of this study is analysis of heat-up process of wet woody particles on a backward acting grate including dynamics motion investigation by implementing XDEM （extended discrete element method） as a novel approach. In this method, the particles are resolved as the discrete phase （individual elements） coupled via heat, mass and momentum transfer to the continuous gas phase. The temperature of particulates along the backward acting grate is investigated by evaluating effects of operating parameters such as bar amplitude and period. Furthermore, the bar motion has effects largely on the heat-up process of the packed bed on the backward acting grate which is considered here as well. In other words, motion of particles caused by bar motion influences the heat transfer of particles and totally the packed bed. In fact, the particles＇ heat-up is performed by a radiative heat flux facing the packed bed surface so that heat transfer of particles as radiation and conduction with surrounding particles is taken into account in addition to convection heat transfer between particles and surrounding gas phase.
基金the National High Technology Research and Development Program(863) of China (No.2007AA05Z215)
文摘Based on the analysis of heat transfer mechanics,physical and chemical change of pellet drying and preheating process in grate,the mathematical model is established and solved by three-diagonal matrix algorithm. With Visual Basic 6.0 a simulation software is developed.The model is verified by measurements at a domestic pellet plant,and the temperature distribution of pellet bed is gained.Meanwhile,the influence of different operation parameters on the pellet thermal process is studied.The results can be taken as a basis of practical production control and the grate optimizing design.
