海水中牺牲阳极阴极保护的分段非线性边界数学模型

A Mathematical Model with Piecewise Nonlinear Boundary for Sacrificial Anode Cathodic Protection in Sea Water

边界条件处理方式是否合理,不仅影响阴极保护体系电位分布的数值解,而且影响模型的应用范围。根据Al-Zn-In牺牲阳极与316L不锈钢在海水介质中的自腐蚀电位差,选用适宜的电位区间及扫速,获得材料实测极化曲线处理非线性边界,建立了牺牲阳极阴极保护系统的非线性边界模型。由于该模型不依赖于极化动力学参数,很大程度上简化了牺牲阳极阴极保护系统的模拟。采用有限元方法进行求解,初步讨论了Al-Zn-In牺牲阳极放置位置、形状和放置方式对被保护316L不锈钢管表面电位分布的影响规律。数值模拟获得的规律与现有的阴极保护理论相符,验证了该模型的可行性。

The way of handling boundary condition not only affects the numerical potential distribution of cathodic protection system, but also affects the application of the model. According to the difference of corrosion potentials of Al-Zn-In sacrificial anode and 316L stainless steel in seawater, the appropriate polarization potential range and scan rate were chosen to measure the polarization curves used for handling boundary conditions and founding a nonlinear boundary model for the sacrificial anode cathodic protection system. The current model which does not depend on the polarization dynamic parameters simplifies the simulation for sacrificial anode cathodic protection. Numerical results of the influences of Al-Zn-In sacrificial anode placement, shape and placement mode on the potential distribution of 316L stainless steel agree well with the existing theory and thus verify the feasibility of current model.