多场耦合作用下氯离子分布场的数值模型

Numerical model of chloride distribution with multi-field coupling

为了研究温度场、湿度场和CO2分布场对氯离子分布场的影响,基于Fick扩散定律和质量守恒定律,主要考虑氯离子扩散系数、湿度以及氯离子结合和释放4个敏感参数,推导了混凝土中氯离子三维分布场控制方程,给出了初始条件和边界条件.利用ANSYS内部集成的参数化程序设计语言APDL建立了数值分析框架.结合试验参数,进行了湿度场作用下混凝土中氯离子分布场的数值计算,并进行了模型参数敏感性分析.结果表明:该模型可以实现不同边界条件下二维和三维多场耦合的数值计算.湿度扩散系数、氯离子扩散系数、边界氯离子浓度以及氯离子结合等温线的取值对氯离子浓度分布影响显著.数值计算结果与实验结果吻合良好,数值模型具有足够的可靠性.

The influence of temperature field,moisture field and carbon dioxide distribution field on chloride diffusion coefficient is studied.Based on Fick＇s second law and mass conservation,the three-dimensional distribution of chloride field equations is derived by considering the four sensitive parameters of chloride diffusion coefficient,relative humidity,chloride binding and chloride release,and the initial conditions and boundary conditions are given.The numerical calculation frame is established by the ANSYS system and its internal integration APDL.Combined with the test parameters,the numerical calculation of chloride distribution field affected by moisture field and sensitivity analysis are carried out.The results show that the two-and three-dimensional numerical calculation of multi-field coupling with different boundary conditions can be done by this model.The chloride distribution is significantly affected by the moisture diffusion coefficient,the chloride diffusion coefficient,the chloride concentration in boundary and the chloride binding isotherm.The numerical results agree well with the experimental results.