Investigation on mass transfer model of drying of porous materials based on exponential diffusion coefficient

Abstract

Establishing mass transfer models of mineral porous materials in wet state is of great significance for understanding the internal moisture distribution and optimizing parameters during drying processes.Based on Lewis-Scherwood drying model, a one-dimensional heat and mass transfer diffusive model by convective drying of porous materials was established by using the dynamic vaporization latent heat and exponential capillary diffusion coefficient.The average relative error of the improved model was determined to be 4.6% by comparing the experimental and the calculated value of water content decrease under the condition of convective drying on three porous material samples.By comparing the improved model, the traditional model using constant latent heat and constant diffusion coefficient, and the results from drying experiment of porous material samples, it is verified that the improved model has higher accuracy than the traditional model.The improved model is suitable for predicting the water distribution in porous mineral materials, which provides a reference for study of the prediction method of the water content in porous mineral materials in different drying conditions.

Keywords

• porous mineral materials
• heat and mass transfer
• material drying