基于指数型扩散系数的多孔材料干燥传质模型研究  

Investigation on mass transfer model of drying of porous materials based on exponential diffusion coefficient

作　　者：张通千 Zhang Tongqian(School of Mechanical Electronic&Information Engineering,China University of Mining&Technology-Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)机电与信息工程学院,北京100083

出　　处：《矿业科学学报》2020年第6期648-654,共7页Journal of Mining Science and Technology

基　　金：国家自然科学基金(50772131);国家“863”计划(2011AA322100);教育部重点项目(106086);中央高校基本科研业务费专项资金(2010YJ05)。

摘　　要：建立含水状态下矿物类多孔材料干燥传质数学模型,对于了解多孔矿物材料内部水分分布以及优化材料干燥参数有重要意义。本文在Lewis-Scherwood干燥模型基础上,采用了动态水汽化潜热值和指数型质扩散系数,建立了改良后表面对流干燥条件下的多孔材料水分一维扩散热质传递模型,通过对3种含水多孔材料试样在表面对流干燥条件下材料内部含水量下降的实验值与计算值的对比,确定了一维扩散模型计算值平均相对误差为4.6%。将改良模型和传统模型的计算结果分别与含水多孔材料试样干燥实验结果进行对比,验证了新模型较传统模型具有更高精度。新模型适用于预测多孔矿物材料内水分分布,为研究不同干燥环境下多孔矿物材料内部含水量预测方法提供了借鉴。Establishing mass transfer models of mineral porous materials in wet state is of great significance for understanding the internal moisture distribution and optimizing parameters during drying processes.Based on Lewis-Scherwood drying model,a one-dimensional heat and mass transfer diffusive model by convective drying of porous materials was established by using the dynamic vaporization latent heat and exponential capillary diffusion coefficient.The average relative error of the improved model was determined to be 4.6%by comparing the experimental and the calculated value of water content decrease under the condition of convective drying on three porous material samples.By comparing the improved model,the traditional model using constant latent heat and constant diffusion coefficient,and the results from drying experiment of porous material samples,it is verified that the improved model has higher accuracy than the traditional model.The improved model is suitable for predicting the water distribution in porous mineral materials,which provides a reference for study of the prediction method of the water content in porous mineral materials in different drying conditions.

关 键 词：矿物多孔材料 热质传递 物料干燥 

分 类 号：TB34[一般工业技术—材料科学与工程]