时域自适应精细算法求解二维非线性湿热耦合问题

Solving 2-D Nonlinear Coupled Heat and Moisture Transfer Problems via a Self-Adaptive Precise Algorithm in Time Domain

采用时域自适应精细算法求解二维非线性湿热耦合问题· 通过在离散时间段上将变量展开,更精确地描述变量的变化过程,将非线性时空耦合的初边值问题转化为一系列递推的线性边值问题,并利用有限元法进行求解· 计算中不需任何附加假设和迭代过程,并提出了自适应计算的收敛判则,以保持时间步长选择不同时的计算精度· 数值比较中,分别考虑了材料属性随温度变化、随湿度变化、以及随温度和湿度变化的情形,结果令人满意。

A self_adaptive precise algorithm in the time domain was employed to solve 2_D nonlinear coupled heat and moisture transfer problems. By expanding variables at a discretized time interval, the variations of variables can be described more precisely, and a nonlinear coupled initial and boundary value problem was converted into a series of recurrent linear boundary value problems which are solved by FE technique. In the computation, no additional assumption and the nonlinear iteration are required, and a criterion for selfadaptive computation is proposed to maintain sufficient computing accuracy for the change sizes of time steps. In the numerical comparison, the variations of material properties with temperature,moisture content, and both temperature and moisture content are taken into account, respectively. Satisfactory results have been obtained, indicating that the proposed approach is capable of dealing with complex nonlinear problems.