Modeling heat and mass transfer-induced stresses in germinated brown rice kernels during fluidized bed drying

作者：Srisang Naruebodee; Soponronnarit Somchart; Thuwapanichayanan Ratiya; Prachayawarakorn Somkiat^*

来源：Drying Technology, 2016, 34(6): 619-634.

DOI：10.1080/07373937.2015.1066385

• Fissure
• fluidized bed drying
• moisture gradient
• stress

A study of stress distribution inside a germinated brown rice (GBR) kernel during drying is important to understand the fissure formation of GBR and hence control the drying process in order to improve the quality of GBR. In this study, a finite element method performed in three dimensions in conjunction with the heat and mass balance of the drying system was developed to describe moisture, temperature, and stress distributions inside GBR kernels during fluidized bed drying. The modeling was carried out using the coupling of heat and mass transfer and validated with experimental data at 90-150 degrees C. The results of moisture and temperature predictions agreed well with the experiments. During drying, tensile stress occurred at the layers close to surface and compressive stress occurred at the inner portion of a kernel. The tensile and compressive stresses increased to the highest value at about 30s of drying, corresponding to the highest moisture gradient, and then decreased afterwards. The tensile and compressive stresses were higher at a higher drying temperature. These stress prediction results corresponded to the experiments, which show more severe GBR fissuring at higher drying temperatures.

• 出版日期2016