AN IMPROVED CROSS-FLOW WHEAT DRYING MODEL FOR EQUIPMENT DESIGN
A simulation program for cross-flow wheat dryers was updated in various respects. The kinetic and geometric parameters of the diffusive thin layer equation, based on newly measured data, depend now on the initial m.c. (W0). The program predicts condensation. Energy equations were slightly altered to better deal with vapor heating. The empirical heat of sorption fit was replaced by a sorption isotherm-Clapeyron expression. The program was revalidated by comparing predicted performance parameters as throughput (8.2%), outlet temperature (2.6°C), heat consumption (10.3%) and outlet germination (8.8%) with test data from actual dryers (errors in parentheses). Predictions are now better, and the program was used to simulate a conventional dryer (bed depth: 0.30 m) as well as variants to improve uneven drying by reversing the airflow, by recycling air and by testing different depths in a given column. First two variants simulated together decreased throughput by 18.2%, and caused little additional damage, though they halved heterogeneity and saved energy consumption by 16%, while improving cooling. Equal throughput is achieved increasing investment by 11%, which can be paid-off in a drying season. Effects of using first a narrower depth to widen it later were mostly positive.
Giner, S.A. (2001). AN IMPROVED CROSS-FLOW WHEAT DRYING MODEL FOR EQUIPMENT DESIGN. Acta Hortic. 566, 467-476
grain drying, drying models, crossflow dryers, dryer simulation, wheat, dryer tests