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This review paper was written on the occasion of the 40th anniversary of the Drying Technology Journal. Interestingly, most of the progress made in the domain of drying modeling and simulation has occurred over the last 40 years. Indeed, 40 years ago, the comprehensive formulation of coupled heat and mass transfer in porous media was available; however, its potential use for computational simulation was only in its nascent stage. This is therefore an ideal time span in which to take a full historical context, to present the state-of-the-art and to give insights into its future trajectory. All aspects are deliberately presented in a pedagogical manner with many illustrations to make the text accessible to young scientists. However, for the benefit of experts, detailed formulations are provided in the annexes. The main points addressed in this work include: The description of the comprehensive macroscopic formulation, An historical perspective of the progress made in computational simulation, The contribution of modeling in parameter characterization, The mechanical aspects of drying: strain and stress induced by drying, including the case of large deformations, The impact of non-local equilibrium, The promising domain of the digital twin in parameter tuning and control/command. [ABSTRACT FROM AUTHOR]

The paper brings new insights into nonsymmetrical convective drying, a configuration in which stresses induce a global change of the section shape of a wooden board with five insulated faces. Two experimental devices that allow to test simultaneously “twin” wooden boards have been developed: the first board is free and its curvature is collected vs. time; the second one is constrained and the force required to keep it flat is collected vs. time. Convective drying tests have been performed on radial specimens of spruce, 5 and 15 mm thick at 45 and 65°C. The results are commented and compared with simulation runs. For this purpose, a 1-D mechanical formulation is embedded in the computational code of heat and mass transfer TransPore. The objective of the comparison between numerical and experimental results is a better understanding of the coupled phenomena and the identification of some transfer and mechanical parameters. [ABSTRACT FROM AUTHOR]

We have developed a model on drying of two tropical woods of ayous ( Triplochiton Scleroxylon ) and frake ( Terminalia Superba ) coming from Cameroon forests. Some thermophysical parameters used in the model were experimentally obtained in this work while the remaining properties were from literature. A comparison is doing between numerical results of our model, these given by the Luikov’s model and experimental data. Numerical simulation results from the developed model give close agreement with experimental results. We note that Luikov’s model not gives a satisfaction results in the non-hygroscopic domain in the case of frake. The present model can be used to explain the drying phenomenon of these two tropical species and can be applied to others species when necessary thermophysical parameters of these species are known. In a future work, it is important to integrate the influence of anatomical direction on our numerical and experimental results. [ABSTRACT FROM AUTHOR]

To assist with the correct design of buildings, many computational models have been developed to assess the transient heat, air, and moisture (HAM) transfer within building walls. Validation of these computational models is essential to gain confidence in the codes. This paper provides datasets for validating 1-D heat and mass transfer models step by step, gradually increasing the complexity of a multilayer wall with hygroscopic components. The experiments were performed using a double climatic chamber. The climatic conditions on either side of the wall progress from the simplest boundary conditions (isothermal) to more complex ones with oscillations that mimic the mid-season period. To assess the hygrothermal response of the tested walls under such climatic conditions, the conditions of ambient air and the temperature and humidity profiles within the wall thickness are monitored during the test. This paper gives some detailed information on the chamber design, the instrumentation, the materials, and the climatic conditions so that other researchers can use the collected data for validation of their models or to build future test facilities. The results obtained with the test facility highlight the coupling that exists between heat and mass transfers across multilayer walls using hygroscopic components. The heat release by moisture adsorption is observed in the temperatures profiles. During the mid-season period, the results show the differences of the phase shift and the amplitude attenuation of the temperature and the water vapour pressure across the wall thickness. [ABSTRACT FROM AUTHOR]

This article proposes a dual-scale computational model of wood drying in a batch lumber kiln. The stack may consist of a large number of boards (typically 100) arranged in layers. Each single board of the stack is simulated using one module of TransPore , a comprehensive computational model for heat and mass transfer in porous media. Timber variability is taken into account by a Monte-Carlo method. Such a dual-scale model allows the drying simulation of a 100-board stack to be completed in less than 30 s on a PC with a 2.8-GHz Xeon processor. Sample simulations are presented to depict the great potential and prospects of this new tool. [ABSTRACT FROM AUTHOR]

Abstract: A comprehensive heat and mass transfer computational model is used to analyse the intricate two-way coupling arising from the activated chemical reactions involved in the heat treatment of wood. The 2D version of a drying code known as TransPore is used to simulate the coupled heat and mass transfer phenomena. This code accounts for the internal pressure in the porous medium. The pyrolysis model describing the chemical reactions occurring in the main constituents within the cell walls of wood (cellulose, hemicelluloses and lignins) is derived using data taken from the literature. Refined computational strategies were required to address the two-way coupling between the heat and mass transfer and chemical mechanisms, including the thermal activation of the chemical reactions, together with the treatment of heat sources (or sinks) and the production of volatiles. The experimental set-up allows the overall weight loss, and the internal temperature and pressure at specific locations within the board to be determined during processing. The reported simulations highlight that the model is able to capture two particular phenomena observed during the heat treatment of wood: the double pressure peak due to water evaporation and volatiles production; and the temperature overshoot during the heat treatment phase. [Copyright &y& Elsevier]