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通过将稳态传质模型和一维电偶腐蚀模型耦合,提出了预测异径管流动加速腐蚀速率的新模型。该模型先由稳态传质模型得到异径管近壁面处的自腐蚀电流密度分布和速度极值点处的自腐蚀电位,而后将极值点处自腐蚀电位代入到一维电偶腐蚀模型中,计算该壁面处的电偶腐蚀电流密度。应用此新模型对某一异径管流动加速腐蚀速率进行计算,发现异径管大端的腐蚀电流密度比小端腐蚀电流密度大两个数量级,据此可以解释台湾某核电站蒸汽冷凝水管线统计得出异径管大端出现最大减薄量的现象。与壁面剪切应力理论和稳态传质理论计算流动加速腐蚀速率分布相比,该模型的计算结果更贴近实际情况。
By coupling the steady-state mass transfer model and the one-dimensional galvanic corrosion model, a new model for predicting the accelerated corrosion rate of the reduced-diameter pipe is proposed. In this model, the self-corrosion current density distribution near the wall of the reducer and the self-corrosion potential at the extreme velocity point are obtained from the steady-state mass transfer model, and then the self-corrosion potential at the extreme point is substituted into the one-dimensional galvanic corrosion model , The galvanic corrosion current density at the wall surface is calculated. Using this new model to calculate the accelerated corrosion rate of a reducer, it is found that the corrosion current density at the large end of the reducer is two orders of magnitude larger than the small-end corrosion current density, which can be used to explain the statistics of steam condensate lines in a nuclear power station in Taiwan Out of the big end there is the phenomenon of reducing the large amount of thinning. Comparing with the theory of wall shear stress and the steady-state mass transfer theory, the calculated results of the model are closer to the actual situation.