摘要
对国内外20多年来灰渣模型研究的进展进行综述,详细的探讨了灰渣形成、灰渣在燃烧场中的运动、灰渣在壁面的碰撞和粘附、灰渣层的成长和强度的变化、通过灰渣层的传热过程以及灰渣层的存在对燃烧工况的影响情况.文章还指出,在研究存在强烈相变的灰渣沉积情况时,现有灰渣模型的假设过于简单.作为补充,文中建立了一种颗粒壁上燃烧模型,给出了主要的计算思路,用于液态排渣炉内灰渣沉积特性的数值研究.
Abstract During the process of coal combustion, the ash deposition may change the wall boundary conditions, which in turn will change heat transfer and burning condition in the coal-fired furnaces. Without considering the diversity and chemistry of coal and coal ash, and the effect of burning conditions on the ash deposition, the conventional prediction methods, such as Clinkering-index and ASTM methods, do not have the necessary precision. Recently, many researchers apply the method of computational fluid dynamics （CFD） to the coal combustion simulation, together with a physical or numerical model for every branch process, to simulate the coal combustion and ash deposition. Their research results provide very important guidance to the design and operation of coal-fired furnaces or boilers. This paper presents a review on the researches of slag models, proposed during recent several decades, including ash formation, ash transportation, ash impaction and sticking, deposit growth and strength development, heat transfer through the slag layer and the effect of deposition on the burning condition. Because most existing numerical methods do not consider the intense phase change rigorously, these models should be modified. As an addition to existing methods, the wall-burning model, whose numerical description is given at the end of this paper, might be used to simulate the ash deposition in the pulverized coal liquid-bath combustion.
出处
《力学进展》
EI
CSCD
北大核心
2005年第3期417-426,共10页
Advances in Mechanics
基金
中国科学院"百人计划"项目和广东省重大科技攻关项目"煤粉低尘洁净燃烧与利用"(2002830803)咨助项目
