Songok Joel, Bousfield Douglas W, Gane Patrick A C, Toivakka Martti
Laboratory of Paper Coating and Converting and Center for Functional Materials, Abo Akademi University, Porthaninkatu 3, FI-20500, Åbo/Turku, Finland.
Department of Chemical and Biological Engineering, University of Maine, 5737 Jenness Hall, 04469, Orono, ME, USA.
Eur Phys J E Soft Matter. 2016 Feb;39(2):25. doi: 10.1140/epje/i2016-16025-6. Epub 2016 Feb 26.
While drying of paper and paper coatings is expensive, with significant energy requirements, the rate controlling mechanisms are not currently fully understood. Two two-dimensional models are used as a first approximation to predict the heat transfer during hot air drying and to evaluate the role of various parameters on the drying rates of porous coatings. The models help determine the structural limiting factors during the drying process, while applying for the first time the recently known values of coating thermal diffusivity. The results indicate that the thermal conductivity of the coating structure is not the controlling factor, but the drying rate is rather determined by the thermal transfer process at the structure surface. This underlines the need for ensuring an efficient thermal transfer from hot air to coating surface during drying, before considering further measures to increase the thermal conductivity of porous coatings.
虽然纸张和纸张涂层的干燥成本高昂，对能源的需求很大，但目前尚未完全了解其速率控制机制。使用两个二维模型作为初步近似，以预测热风干燥过程中的热传递，并评估各种参数对多孔涂层干燥速率的作用。这些模型有助于确定干燥过程中的结构限制因素，同时首次应用涂层热扩散率的最新已知值。结果表明，涂层结构的热导率不是控制因素，干燥速率而是由结构表面的热传递过程决定的。这突出了在考虑进一步提高多孔涂层热导率的措施之前，确保干燥过程中从热空气到涂层表面高效热传递的必要性。
