快速干燥过程中多孔介质内部湿分挤压流动的研究

提出了简化的弯通道模型.根据多孔物料的结构和干燥过程的特点,通过实验观测湿分在一定压力差作用下的迁移行为,着重研究快速干燥过程中多孔介质内部湿分的挤压流动现象.实验结果表明在一恒定温度下,当干燥物料两端的压力差逐渐增大时,湿分由物料内部到达外表面所需的时间逐渐减小且在相同的压力差降下,时间减小的幅度越来越小.在相同的压力差下,当液体温度升高时,湿分由物料内部到达外表面所需的时间随之减小.

Research on Displacement Flow of Internal Moisture in Porous Media During Rapid Drying Process

In this paper, the authors put forward the idea that the displacement flow in capillary structure under pressure gradient is the main mechanism of high intense and rapid drying process. In this paper, both analytical and experimental studies are carried out to clarify the displacement process and its characteristic. A simplified displacement flow model is proposed and the time of the moisture migration is calculated. A one dimentional displacement flow test device is built up and a set of experiments under different pressure gradients and temperatures are conducted. Glass beads of 0 8mm diameter are used as the porous material. The experiment results show that under a constant temperature, as the pressure gradient is getting greater, the time for moisture to reach the external surface from the internal is getting smaller and the range of time reducing is getting smaller too. On the other hand, under the same pressure gradient, as the liquid temperature increases, the time for moisture from the internal to the external surface decreases.