粮粒水分扩散方程的由来及研究进展

The Origin and Progress in the Equations of Moisture Diffusivity of Grains

粮粒具有吸湿性,它随周围环境的变化而解吸或吸收水分。单一粮粒或粮堆的解吸或吸附行为,依赖于粮食种类的物理特征。文章介绍了恒定干燥速率、速率降低干燥阶段的概念,以及描述速率降低干燥阶段的理论和经验方程,尤其是水分扩散方程或薄层干燥方程的推导过程,并指出了各种水分扩散方程描述粮粒解吸或吸附速率的优缺点。

Grains are hygroscopic and adsorp or desorp moisture from their surrounding air. The sorption behavior of a grain kernel, or of a collection of grain kernels depends on the physical characteristics of the grain species. This review introduces constant-rate drying period and falling-rate drying periods, the theoretical and empirical drying equations for falling-rate drying, especially the derivation of moisture diffusivity equation or thin-layer drying equation, and evaluate the effect of various diffusivity equation on describing the desorptive or adsorptive rate of a grain kernels. It was referred that the physical characteristics of a grain kernel of each species should be studied during moisture adsorption.