Radio frequency vacuum drying of wood. II. Experimental model evaluation

Thick specimens of two softwoods were dried in a laboratory radio frequency /vacuum (RF/V) dryer to investigate the evolution of internal moisture flow patterns. The total average moisture content and local temperatures and pr essures were monitored as a function of time. A number of runs were carried out for different conditions of voltage, power density, ambient pressure, core temperature, and initial moisture content. The results obtained were c ompared with the ones predicted by a 1D simplified model. Despite the simpl icity of the model, good agreement was obtained for a variety of drying con ditions, especially in predicting the average moisture evolution and the dr ying time.