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基于两相流理论,提出了一个描述含湿氧化铝颗粒气流干燥过程的一维数学模型.模型考虑了干燥管内气固两相间的传热和传质、气固两相温度和含湿量的变化.利用Bird等所提出的努赛尔数经验公式对该气流干燥模型进行了数值计算,得到了含湿氧化铝颗粒在不同气流干燥条件下的干燥曲线.整个干燥过程的数值模拟结果与实验数据吻合得很好,可以用来预测含湿氧化铝颗粒的干燥湿度.另外,对固气比、气流温度以及气流速度对颗粒湿度沿干燥管高度变化的影响也作了计算和分析,结果表明固气比和气流温度对颗粒湿度的变化影响较大.低固气比、高气流入口温度,干燥过程颗粒湿度变化大,有利于颗粒干燥.而气流速度对颗粒湿度变化的影响则可忽略不计.
Based on the theory of two-phase flow, a one-dimensional mathematical model describing the drying process of wet alumina particles is proposed.The model considers the heat and mass transfer, gas-solid two phase temperature and moisture content The numerical simulation of the drying model was carried out by using the Nusselt number empirical formula proposed by Bird et al and the drying curves of the alumina-containing particles under different air-flow drying conditions were obtained.The numerical simulation results and experiments of the whole drying process The data are in good agreement and can be used to predict the moisture content of the wet alumina particles.On the other hand, the effects of the solid-gas ratio, the gas temperature and the gas velocity on the particle humidity along the height of the drying tube were also calculated and analyzed. The solid-gas ratio and the temperature of the air flow have a great influence on the change of the particle humidity, and the low solid-gas ratio, the high air inlet temperature and the change of the particle humidity in the drying process are large, which is beneficial to the particle drying. .