脉动燃烧尾气干燥过程质量传递特性  

Mass Transfer between Materials and Unsteady Airflow from a Helmholtz Type Combustor

作　　者：牛海霞[1] 刘榴[1] 赵文河 刘相东[1] 

机构地区：[1]中国农业大学工学院,北京100083 [2]山东天力干燥设备有限公司,济南250014

出　　处：《农业机械学报》2011年第1期129-133,共5页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家高技术研究发展计划(863计划)资助项目(2007AA05Z217)

摘　　要：在Helmholtz型脉动燃烧器尾管中进行了耐火土颗粒的干燥实验,通过干燥法中的简化法确定了不同频率下物料内部的水分扩散系数。应用费克第二定律,结合适当的初始条件和边界条件,并根据实验确定不同频率下脉动气流与耐火土颗粒间的对流传质系数,探讨脉动频率对脉动燃烧干燥过程中气流与物料间的对流传质系数的影响,建立了修伍德数与脉动频率间的关联式。结果表明,在干燥过程中气流的脉动可强化物料内部水分扩散,脉动气流传质的修伍德数远高于相同雷诺数下稳定紊流中的数值。Although pulse combustion drying would exhibit high rate of mass transfer when used in a drying process,there is no numerical research about the mass transfer between materials and unsteady flow generated by pulse combustor.The results of an investigation of the moisture diffusivity in refractory clay and the convection process of moisture between refractory clay and outflow was reported.A Helmholtz type pulse combustion was used to generate an oscillating airflow.The moisture diffusivity in refractory clay was determined by the simplified method of drying methods.The mass transfer coefficient between refractory clay and outflow was evaluated by the results of experiment and Fick＇s second law with reasonable initial conditions and boundary conditions.The effect of airflow oscillating frequency on mass transfer coefficient was investigated and the correlation was established.

关 键 词：耐火土 脉动燃烧 干燥 传质 

分 类 号：S226.6[农业科学—农业机械化工程] TQ021.4[农业科学—农业工程]