油菜籽流化床恒速干燥传热传质特性及模型研究  

Heat and mass transfer characteristics and model of rapeseed (Bassica rapus) fluidized-bed drying with constant drying rate

作　　者：张健平[1] 赵周能[2] Zhang Jianping Zhao Zhouneng(Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China School of Environment and Resource, Southwest University of Science and Technology, Mianyang 621010, China)

机构地区：[1]西南科技大学制造过程测试技术教育部重点实验室,绵阳621010 [2]西南科技大学环境与资源学院,绵阳621010

出　　处：《农业工程学报》2017年第13期287-295,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(51308480);教育部在线教育研究基金(2016YB163);博士研究基金项目(17ZX7125)联合资助

摘　　要：在油菜籽干燥过程中,干燥工艺(热空气温度、速度和油菜籽初始含水率)主要影响着恒速干燥阶段的传热、传质系数,为此该文基于恒速干燥阶段,借助流化床干燥试验装置,试验分析了油菜籽初始含水率、热空气温度、热空气流速对油菜籽流化床干燥对流传热、传质系数的影响,结果表明:各影响因素的敏感性主次顺序为油菜籽初始含水率>热空气温度>热空气流速,其中油菜籽初始含水率为29.72%的对流传热、传质系数约为含水率14.41%的1.9倍,2.25 m/s热空气流速的对流传热、传质系数约为1.75 m/s的1.2倍,65℃热空气温度的对流传热、传质系数分别约为45℃的1.2倍和1.4倍。为此,以对流传热、传质系数为性能指标,根据Box-Behnken试验设计原理,应用Design-Expert 8.0.6软件,建立了影响因子与性能指标的回归模型,通过验证发现对流传热、传质系数两个模型预测值与试验值的最大相对误差仅为4.83%和4.79%,表明该两个回归模型拟合度较好,可靠性较高。研究结果可为强化传热传质提高油菜籽流化床干燥效率提供理论依据,同时也为生产工艺条件选择和干燥设备设计提供理论支撑。The rapeseed oil is one of the main edible vegetable oils in China and the third largest edible vegetable oil all over the world. It is easier to mold under the high temperature and humidity because the rapeseed has more protein and very small porosity. Therefore, the fresh rapeseed is hard to be safely stored. At present, the traditional solar drying method of rapeseed can hardly meet the requirements of rapeseed drying in China. For the timely safe storage, artificial drying methods must be employed, among which the hot-air fluidized-bed drying is commonly applied. The principle of the rapeseed fluidized-bed drying is extremely sophisticated because it is often associated with impaired heat transfer, mass transfer, and momentum transfer. The convective heat and mass transfer coefficient are key influence factors to the drying efficiency and the drying quality of rapeseed fluidized-bed drying. In brief, the changing regularity of convective heat and mass transfer coefficient, and the measures on improving convective heat and mass transfer have become the vital problems concerning the timely safe storage of fresh rapeseed. In order to investigate the changing regularity of convective heat and mass transfer of the rapeseed fluidized-bed drying, the influence of the initial moisture content, the hot air temperature, and the hot air velocity on the convective heat and mass transfer coefficient was analyzed by using experiment equipment of rapeseed fluidized-bed drying. The results showed that the convective heat and mass transfer coefficient increased with the increase of the initial moisture content, the hot air temperature, and the hot air velocity. And the primary and secondary order of the factor influencing the convective heat and mass transfer coefficient was： the initial moisture content, the hot air temperature, and the hot air velocity. The convective heat transfer coefficient and the convective mass transfer coefficient of the rapeseed with 29.72% initial moisture content were both 1.9 times that with 14

关 键 词：干燥 传热 模型 油菜籽 流化床 对流传热系数 对流传质系数 

分 类 号：TQ021.3[化学工程] TQ026.7