不同进风方案下隧道烘干窑热风流场CFD模拟和优化  

CFD simulation and optimization of airflow field in industrial tunnel dryer with different blowing designs

作　　者：师建芳[1] 吴中华[2] 刘清[1] 娄正[1] 赵玉强[1] 朱明[1] 

机构地区：[1]农业部规划设计研究院农产品加工工程研究所,北京100125 [2]天津科技大学机械工程学院,天津300222

出　　处：《农业工程学报》2014年第14期315-321,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：公益性行业(农业)科研专项(200903009);公益性行业(农业)科研专项(201003007)

摘　　要：隧道烘干窑内同一横截面的热风均匀性影响着物料干燥均匀性和产品质量,而烘干窑入口风速分布直接影响着窑内热风流场的均匀分布。为了解决单一风机直进风隧道烘干窑存在的风速不均匀问题,提出了多种进风结构设想,并利用计算流体力学方法对实际生产的隧道窑进风流场进行数值模拟,研究3种不同的进风方案(4风机、6风机和9风机)对隧道窑内热风流场均匀性的影响。模拟结果表明:6风机方案下隧道窑入口处进风均匀,热风扩散距离短,窑内热风流场整体均匀性较佳,综合性价比最高。研究结果为隧道窑入口进风的设计提供参考。The tunnel dryers with direct blowing are widely applied to dry agricultural products in Chinese rural area. While in practice, the existing single fan blowing designs were found to cause a non-uniform gas velocity distribution inside the tunnel, which results in a non-homogeneous drying quality of the dried product. To address this problem, a multiple fans blowing design concept was proposed in this paper and its feasibility was evaluated by using the computational fluid dynamics （CFD） modeling method. In this paper, the CFD model was developed to simulate the cold flow field inside the tunnel dryer and thus the drying process was ignored at the present stage. The self-developed CFD model consisted of governing equations and suitable boundary conditions. The governing equations comprised of the mass, momentum conservation ones, the K-epison turbulent ones. The boundary conditions were set according to the actual operation conditions of the tunnel dryer and included the velocity inlet, pressure outlet, and non-slip boundary ones. The mathematical model was solved using a commercial CFD software-Fluent 6.3. The flow field inside an industrial tunnel dryer with a single fan blowing used for the drying of cowpeas was measured experimentally and simulated using the above CFD model. The CFD simulation results were compared with the experimental data to validate the CFD model. Both the simulation and experimental results showed that a strong, hot air inlet jet with a velocity of 9 m/s was formed under the air flow rate of 6 300 m3/h. The strong air jet would diffuse completely after 10 m of the whole dryer length of 15 m, causing a big non-uniform gas velocity distribution inside the tunnel dryer. Aiming to reduce the strong air jet forming in the single fan blowing design, four, six, and nine fans blowing designs were proposed and their gas velocity distributions were also simulated using the CFD model. It was found that when keeping the air flow rate of 6 300 m3/h, the complete diffusion distance of the inlet air

关 键 词：计算流体力学 数值分析 干燥 流场 热风干燥 隧道式烘干窑 

分 类 号：S375[农业科学—农产品加工]