天然气炉窑干燥过程多孔介质传热传质耦合数值分析

Numerical Analysis of Coupled Heat and Mass Transfer in Porous Media within Adobe Drying Process in Industrial Furnace

砖坯的干燥是其塑性成型的逆过程,干燥过程涉及相变及多孔介质传热传质的耦合问题,文章从非稳态传热传质和相平衡的角度出发,基于多孔介质传热传质和计算流体动力学基础理论,建立了砖坯干燥过程的非线性三维数学模型,利用流体计算软件FLUENT对模型进行求解,得到砖坯干燥过程中内部含湿量和温度的变化过程,讨论了干燥介质入口速度和温度对干燥过程的影响,结合所得的干燥数据以及临界干燥温度梯度,利用Matlab对干燥介质入口速度、温度与干燥时间的关系进行拟合,得出在小于本文所设定的临界梯度的条件下,较为经济的干燥条件是温度为550~573 K,风速为0.5~2.5 m/s。

Adobe drying is the inverse process of plastic molding and involves phase change and coupling of heat and mass transfer. From the perspective of unsteady heat and mass transfer and phase equilibrium, a three dimensional mathematical and computational model based on porous heat and mass transfer and computational fluid dynamics theories was established in this paper. By using the fluid calculation software FLUENT, the changing process of moisture content and temperature in the adobe was obtained. The influence of drying medium inlet velocity and temperature on drying process was discussed. Combining the drying datum and the critical drying temperature gradient, the relationship of drying medium inlet velocity, temperature and drying time was fitted by Matlab. Results show that the more economical drying condition is that the temperature is 550-573 K, and the wind speed is 0.5-2.5 m/s under the condition of less than the critical gradient set in this paper.