73C-31 |
Extending the capability of ANSYS to simulate the biomechanics of rice drying |
X. YANG1, W. Yang, T. J. Siebenmorgen, and C. Jia. (1) Department of Food Science, University of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704 Computer simulation is a useful too for understanding the biomechanics of rice during drying. Traditionally, researchers solved heat/mass transfer equations through the self-developed codes. With the advancement of computer technology, some sophisticated commercial software, such as ANSYS, has been developed. ANSYS has been widely used in chemical, civil and mechanical engineering. Limited application has been made to agricultural and food engineering. In this study, the capability of ANSYS was extended to study the biomechanics of rice drying. Our objective was to predict temperature, moisture and stress distributions and fissure occurrence inside rice kernels using ANSYS. Rice was dried in a thin-layer dryer at 60°C and 17% RH with moisture and temperature profiles recorded. PLANE13 (a 2-D elastic element) was used to test the ANSYS codes written for this study. A rough rice kernel was regarded as a 2-D elliptical composite that consisted of endosperm, bran, and hull. Three-node triangular elements were used to divide the rice kernel. VISCO88 (a 2-D viscoelastic element) was used to compute the moisture and temperature profiles and stress distribution inside the rice kernel during drying. The simulation was verified against measured temperature at selected nodes and measured average moisture content of rice kernels. The predicted fissure occurrence was compared to the fissuring pattern of rice kernels observed using a light box and video microscopy. ANSYS codes written have been complied and tested for the PLANE13 and VISCO88 elements. Results showed after 3 minutes, the temperatures at all nodes reached the drying temperature (60°C). Both the simulated temperature and moisture profiles agreed well with the measured values. The predicted location of maximum Von Mises stress seemed to support the observation that a majority of fissures are vertical to the long axis of rice kernels, although further experimental verification is needed. Using ANSYS greatly facilitated the simulation of rice drying. It has provided a useful tool to understand the biomechanics of rice during drying and help identify ways to improve the milling quality of rice.
Session 73C, Food Engineering: Transport Processes and Kinetics
|