CAJ | 학술논문

采用两种改进的多孔固体材料水分扩散偏微分方程分析求解方法,即Dincer方法与Crank方法,分析并计算落叶松干燥过程的水分扩散系数(D)与水分传递系数(k).使用扩散型微分方程对落叶松干燥过程进行数学模拟,木材试件被理想化为无限大平板状材料,假定木材内部水分的扩散过程是一维的.实验测定了不同干燥介质条件下木材干燥动力曲线.基于取得的实验数据,通过Dincer方法计算了木材水分扩散系数(D)与水分传递系数(k);使用传统的Crank方法分析计算了木材动态水分扩散系数(D).研究表明,使用Dincer方法计算的木材水分扩散系数(D)均大于相应实验条件下Crank方法计算数值,接近1个数量级.这种结论应该是由于两种分析求解方法间的差异以及水分扩散与热量传递数学求解间的差异.因此相关的水分扩散微分方程的分析求解方法有待改进.随干燥介质温度的升高,木材水分扩散系数(D)与水分传递系数k均显著增大,可以采用Arrhenius方程与木材结合水传递理论来分析解释实验条件下的扩散系数(D)与干燥介质温度(T)间的变化趋势.图2表3参6.
채용량충개진적다공고체재료수분확산편미분방정분석구해방법,즉Dincer방법여Crank방법,분석병계산락협송간조과정적수분확산계수(D)여수분전체계수(k).사용확산형미분방정대락협송간조과정진행수학모의,목재시건피이상화위무한대평판상재료,가정목재내부수분적확산과정시일유적.실험측정료불동간조개질조건하목재간조동력곡선.기우취득적실험수거,통과Dincer방법계산료목재수분확산계수(D)여수분전체계수(k);사용전통적Crank방법분석계산료목재동태수분확산계수(D).연구표명,사용Dincer방법계산적목재수분확산계수(D)균대우상응실험조건하Crank방법계산수치,접근1개수량급.저충결론응해시유우량충분석구해방법간적차이이급수분확산여열량전체수학구해간적차이.인차상관적수분확산미분방정적분석구해방법유대개진.수간조개질온도적승고,목재수분확산계수(D)여수분전체계수k균현저증대,가이채용Arrhenius방정여목재결합수전체이론래분석해석실험조건하적확산계수(D)여간조개질온도(T)간적변화추세.도2표3삼6.
Two analytical procedures (Crank's method and Dincer's method) for porous solid materials were reevaluated and used to determine moisture diffusion coefficients and moisture transfer coefficients for larch lumber subjected to drying. A diffusion-like equation was used to describe drying process data. The lumber was idealized in the modeling as infinite plates. The moisture transport process inside the board was assumed to be one-dimensional. The macroscopic drying kinetics curves of larch timber at particular conditions were determined experimentally. Based on these data, calculation for both the moisture diffusion coefficients and moisture transfer coefficients by the Dincer's analytical procedure were made. The dynamic moisture diffusion coefficients by the traditional Crank's method were calculated. In general, diffusion coefficients calculated by the Dincer's method were all higher than those by Crank's method. These results could be due to the differences between two analytical methods and also different characteristics between solid moisture diffusion process and heat transfer process. Therefore the analysis and solution procedures of moisture diffusion differential equations need to be adapted in the future. With drying temperature's increasing moisture diffusion coefficient (D) and moisture transfer coefficient (k) increases accordingly. Also the relationships between diffusion coefficients and temperature as well as material moisture contents were analyzed by using Arrhenius equation and bound water transport theory.