The measurement of thermal diffusivity of grains such as wheat, rice and barley becomes impracticable with methods that depend on the introduction of sensors inside the grain. In this study a method was proposed to determine the thermal diffusivity of grain considering the variations of the mass diffusivity of grains submitted to different compacting levels. Temperature was measured in internal points and in the border of cylinders of grain mass, for three compacting levels. The thermal diffusivity of grain mass was estimated solving the inverse problem. The heat transfer problem (direct problem) was solved numerically by the finite differences method. With the values of the thermal diffusivity for the three compacting levels, a function was fitted relating the grain mass diffusivity and density. This function was used to project the value of grain diffusivity as a function of measured grain density. The result obtained for soy bean is compatible with the existing data found in the literature. The precision of the method depends strongly on the experimental data quality and grain position density in the researched data interval of the grain mass density.
inverse problems; grain drying; Glycine Max (L.)
