SIMULATION OF PINUS-RADIATA VENEER DRYING - MOISTURE-CONTENT AND TEMPERATURE PROFILES

A mathematical model for timber drying has been extended to the drying of veneer from which the drying curves, moisture content, and tempera ture profiles in veneer wood are predicted. The simulation results ill ustrate that the whole drying process can be divided into three period s: a constant drying-rate period followed by two falling-rate periods. The falling-rate curves could be expressed by two segment lines as a function of veneer average moisture content. Industrial-scale drying t ests were performed to verify the model. In the tests, 2.6 mm Finns ra diata veneer sheets both of sapwood and heartwood were dried at dry-bu lb temperatures of 155 degrees C to 200 degrees C and wet-bulb tempera tures of 65 degrees C to 95 degrees C. The average impinging air veloc ity in drying was 12.3 m/sec. The close agreement between the measured and the predicted moisture contents after drying gives confidence in applying the model in further work to examine the influence of veneer variables and drying conditions on the drying rate.