Numerical simulation of a solar wood dryer

Abstract

This article addresses a comprehensive analysis of the fluid dynamics in an Oxford-type solar kiln for wood drying. The work focused on a solar dryer located in Tacuarembó (Uruguay) and the approach is both experimental and numerical. A detailed analysis of the internal fluid dynamics in this type of kiln is essential to improve drying efficiency and avoid heterogeneous drying, which can lead to defects such as wood warping and reduced mechanical properties. It is well known and widely analyzed in the literature that ensuring homogeneous flow in the wood castle is crucial to avoid these problems. To address these challenges, an experimental analysis was performed to characterize the flow behavior inside the kiln. Additionally, numerical simulations were performed with OpenFOAM, incorporating a fan model based on data provided by the manufacturer. A rigorous mesh convergence study validated the numerical results with experimental measurements. The simulations revealed key flow characteristics, including stagnation zones, recirculation areas, flow diversion around the stack, and flow heterogeneity within the stack. Potential modifications to the furnace design are proposed to improve flow uniformity and minimize air diversion, leading to improved dryer performance.