Problems and solutions in wood drying modelling: History and future
Problems and solutions in wood drying modelling: History and future
复制标题
木材干燥建模中的问题和解决方案：历史与未来
DOI：
10.1080/17480272.2010.498056
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发表时间：
2010
影响因子：
2.2
通讯作者：
J. Salin
中科院分区：
文献类型：
--
作者：
J. Salin
摘要本文回顾了近30年来木材干燥模型的发展历程。文中还讨论了遇到的一些问题及其解决方法。最后，提出了一些尚待解决的问题。随着个人电脑的普及，建模工作大大增加。菲克方程的数值解变得很容易，并提出了第一个有希望的干燥过程的模拟。模型需要材料参数的数值，如扩散系数，模型用于调整数值以使其与试验结果有很好的拟合。外界的热质传递一直是人们讨论的话题。不幸的是，人们对表面排放概念投入了大量的工作，但从实际角度来看，这一概念被证明是无用的。这个领域的另一个问题是明显偏离了热和传质之间的类比。直到最近，这些外部转移问题才得到解决，或者至少得到了理解。随着水分迁移模型达到了合理的精度水平，重点转向了水分诱导应力的计算。这需要建立机械吸附蠕变行为的模型，这是一个仍未完全理解的课题。最初，只开发了低温单板模型，但逐渐包括了其他领域，如窑炉范围的模型、能源消耗、干燥成本、变形和沸点以上的温度。仍然需要研究和开发的领域包括模拟毛细管网络中的游离水行为、包括吸附滞后、环境影响和模拟变色。最后，应该强调技术转让的重要性，技术转让的形式是窑操作员易于使用的模型和窑控制系统中的嵌入式模型。
Abstract This paper gives a historic overview of wood drying modelling during the past 30 years. Some of the problems encountered and their solutions are discussed. Finally, some remaining problems that require solutions in the future are presented. The modelling work increased strongly when personal computers became widely available. Numerical solutions of Fick's equations became easy and the first promising simulations of the drying process were presented. The models required numerical values for material parameters such as the diffusion coefficient and models were used for adapting values to have a good fit with test results. External heat and mass transfer was a subject for discussion for a long time. Unfortunately, a lot of work was devoted to the surface emission concept, which has turned out to be useless from a practical point of view. Another problem in this field was the apparent deviation from the analogy between heat and mass transfer. Only recently have these external transfer problems been solved, or at least understood. As moisture migration modelling had reached a reasonable level of accuracy, the focus turned towards the calculation of moisture-induced stress. This required modelling of mechanosorptive creep behaviour, which is a subject that is still not fully understood. Initially, only low-temperature, single-board models were developed, but gradually other areas were included such as kiln-wide models, energy consumption, drying costs, deformations and temperatures above the boiling point. Areas that still require research and development include modelling free water behaviour in the capillary network, inclusion of sorption hysteresis, environmental impact and modelling discolouration. Finally, the importance of technology transfer in the form of easy-to-use models for kiln operators and embedded models in kiln control systems should be emphasized.