本文采用计算流体动力学(CFD)Fluent软件，构建了辊道窑急冷段三维物理模型，并采用非结构化四面体网格对模型进行网格划分，选择标准K-两方程湍流模型，设置边界条件，对辊道窑急冷段内气体流动进行数值模拟，研究了急冷风速对急冷段内气体流动的影响。结果表明：增加急冷风速可减小管内风速和喷风小孔风速各自沿管长方向的差别，从而使管内急冷风温度沿管长方向分布更趋近均匀，同时也使沿管长方向相应各处的温度更低。适当增加急冷风速有助于加强砖坯与急冷风之间的对流换热，提高砖坯的冷却速率。但急冷风速增加过大时，会使气流速度沿窑宽方向相差较大，导致窑内宽两侧有较大温差，极可能使制品产生风裂或色差等烧成缺陷。%For the numerical simulation study on the inlfuence of air-splat cooling velocity on gas-lfow in the splat cooling zone of roller hearth kiln, the 3D physical model was constructed and meshed with tetrahedral grid by using CFD Fluent software. The standard K- two-equation turbulent lfow model was selected and the boundary conditions were set. The results show that increasing air-splat cooling velocity contributes to reduced difference of the velocity of air-splat cooling in tube as well as of air spraying from tiny holes along the length of tubes, which makes the temperature distribution of air-splat cooling in tube more even and the temperature of the corresponding location along the length of tubes lower. The appropriate increase of air-splat cooling velocity also can enhance the convection heat transfer between green bricks and air-splat cooling and further increase the cooling rate of green bricks, while an unreasonable rise in air-splat cooling velocity can cause the more serious difference in gas-lfow velocity distribution along the width of kiln. Consequently, the more difference in temperature between both sides of kiln width occurs, which probably leads to several ifring defects such as crack in brick, body tint and unevenness, etc.
展开▼
