Mathematical Model for Moisture Diffusion in Stored Grain Due to Temperature Gradients

Abstract

Seasonal variations in ambient temperatures can cause safe moisture contents of stored grain to become unsafe due to migration or redistribution of moisture within the storage. Such migration of moisture generally occurs due to thermal gradients in the stored grain and depends on various factors related to the grain quality, bin size, and local climatic conditions. In this article, a mathematical model for the simultaneous heat and moisture transfer is developed by incorporating a sorption isotherm relationship to predict moisture migration in stored grain due to diffusion. The coupled, nonlinear transport equations are solved numerically by using a control-volume scheme. The predicted results show good agreement with the available experimental data in the literature. This model is also applied to predict moisture migration under conditions approximating winter and summer storage periods. The predictions of moisture and temperature distribution are consistent with field observations.