Zhongguo youzhi (Apr 2023)
基于Pielou指数的油茶籽平板烘干机 干燥过程中含水率均匀性优化Optimization of moisture content uniformity in the drying process of oil-tea camellia seed plate dryer based on Pielou index
Abstract
为改善油茶籽平板烘干机烘干效率低、烘干不均匀等问题，在计算流体力学的理论基础上，建立了多孔介质内部热湿耦合模型，编写UDF程序，利用FLUENT软件模拟并试验验证了该模型的可靠性。引入传统含水率均匀性指数（Mu），与基于Pielou指数的含水率均匀性指数（Jsw）相互对照验证。通过仿真计算研究了烘干机结构、进风角度及运行参数对干燥后油茶籽含水率及其均匀性的影响。结果表明：Mu与Jsw都可作为含湿多孔介质材料含水率均匀性评价指标；中部进风两侧出风结构的烘干机相较于原结构烘干机平均含水率下降，含水率均匀性大大提高；当进风角度向下偏转30° 、热风风速为5 m/s、热风温度为80 ℃、加热平板温度为85 ℃时，油茶籽含水率相较于原结构烘干机从7.94%降至4.76%，Jsw由25.5%提高至83.2%。通过基于Pielou指数的油茶籽平板烘干机干燥过程中含水率均匀性优化，烘干效率和烘干均匀性均明显提高。 To improve the problems of low drying efficiency and uneven drying of oil-tea camellia seed plate dryer, based on the computational fluid dynamics, a heat moisture coupling model in porous media was established, UDF program was written and the reliability of the model was verified by FLUENT software simulation and experiments. The traditional moisture content evenness index Muwas introduced and compared with the moisture content evenness index Jsw proposed on the basis of Pielou index. Through simulation calculation, the effects of dryer structures, air inlet angles and operating parameters on the moisture content of oil-tea camellia seeds and its uniformity after drying were studied. The results showed that both Mu and Jsw could be used as evaluation indexes of moisture content uniformity of materials such as wet porous media. The average moisture content of the dryer with air inlet in the middle and air outlet on both sides of the air duct was lower than that of the dryer with the original structure, and the uniformity of moisture content was greatly improved. When the air inlet angle was deflected downward by 30°, the hot air speed was 5 m/s, the hot air temperature was 80 ℃ and the heating plate temperature was 85 ℃, the moisture content of oil-tea camellia seeds was reduced from 7.94% to 4.76% compared with the original structure dryer, and Jsw increased from 25.5% to 83.2%.Through the optimization of moisture content uniformity in the drying process of oil-tea camellia seed plate dryer based on Pielou index, the drying efficiency and uniformity are significantly improved.
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