开放式太阳能物料干燥热湿迁移模型的构建及验证  

Modeling of materials heat and moisture transfer in open sun drying and experimental validation

作　　者：郝文刚[1] 陆一锋 赖艳华[1,2] 张宗敏 吕明新 Hao Wengang Lu Yifeng Lai Yanhua Zhang Zongmin Lu Mingxin(School of Energy and Power Engineering, Shandong University, Jinan 250061, China Suzhou Institute of Shandong University, Suzhou 215021, China)

机构地区：[1]山东大学能源与动力工程学院,济南250061 [2]山东大学苏州研究院,苏州215021

出　　处：《农业工程学报》2017年第15期301-307,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(51476093);山东省科技发展计划项目(2013GGX10403);苏州市科技发展计划(ZXG201443);山东大学基本科研业务费资助(2014YQ007)

摘　　要：基于开放式太阳能物料干燥过程中存在干燥品质不可控、随机性较大的问题。根据传热传质理论知识,建立开放式太阳能物料干燥热湿迁移预测模型,在综合考虑太阳能辐射、室外空气温湿度、室外风速等影响因素的基础上,对模型中的参数进行选择,并利用MATLAB软件编制求解程序,该模型能够预测出干燥过程中物料表面的温度及水分迁移速率变化。为验证模型的准确性,以红薯为干燥物料对其开放式太阳能干燥过程进行试验测试。结果表明:物料表面温度、水分迁移速率的模拟值与试验值之间的决定系数分别为0.96、0.89,均方根误差分别为0.97℃、28.35 g,其相关性程度较高,说明该模型能够较准确预测开放式太阳能物料干燥过程中物料表面温度及水分迁移速率,可以用于开放式太阳能干燥的工艺控制。Open sun drying has been widely applied in the developing country. It is a popular, effective and economic method for drying and preservation of agricultural products and food, but it has some drawbacks such as degradation of materials quality and larger drying period in ambient environment. In order to solve the problem of uncontrollability and randomness in the process of open sun drying, heat and moisture transfer model of open sun drying materials was studied with theoretical knowledge of heat and mass transfer in this study, and heat and moisture transfer mechanisms of open sun drying materials were analyzed. The heat exchange process of dry materials in the open sun drying process mainly included the absorption of solar radiation heat, the convective heat exchange with the surrounding environment, the heat transfer of long wave radiation and latent heat by water evaporation. Thermal resistance and thermal energy diagram of drying materials was built. Heat balance equation of materials was also built based on energy balance principle, and model parameters were determined by comprehensively considering solar radiation intensity, ambient air temperature and humidity, and ambient wind velocity; the dynamic temperature change of material surface and the water transfer rate of material were predicted, the program was solved by using MATLAB software, and the initial values required for the solution of the model were derived from the experiment data. To verify the accuracy of prediction model, sweet potato was selected as drying material in the open sun drying test. The tested samples of sweet potato were sliced uniformly in terms of size and thickness, the initial mass of sweet potato was 240 g, and the thermal performances and drying characteristics of sweet potato in the open sun drying were investigated in the Qianfo mountain campus of Shandong University. The test period was from 8：30 to 17：00 on May 7, 2017. The test parameters included solar radiation intensity, outdoor air temperature and humidity, surf

关 键 词：热传递 模型 干燥 开放式太阳能 非稳态 干燥特性 

分 类 号：S625.1[农业科学—园艺学] TU111.3[建筑科学—建筑理论]