牺牲阳极参数对直翼桨阴极保护效果影响研究

Influence of Sacrificial Anode Parameters on Cathodic Protection for Cycloidal Propellers

目的研究牺牲阳极设计参数对直翼桨结构阴极保护效果影响,为直翼桨的阴极保护设计和工程应用提供参考。方法针对直翼桨型船用推进器结构,基于边界元法建立数值仿真模型,开展直翼桨牺牲阳极阴极保护仿真计算,重点研究不同牺牲阳极数量、尺寸和布置位置时,直翼桨上箱体、旋转箱体、桨叶和桨叶上端盖等结构的电位分布情况,核算牺牲阳极使用寿命。结果采用Al-Zn-In-Mg-Ti铝合金牺牲阳极时,牺牲阳极数量增多和尺寸变大都会提高直翼桨的阴极保护效果,同时延长牺牲阳极使用寿命。牺牲阳极布置位置的改变会影响直翼桨桨叶表面的电位梯度,改变直翼桨结构的保护电位分布。采用10块0.18D×0.11D×0.04D(D为直翼桨直径)的水滴形高效铝合金牺牲阳极在桨叶间单层布置,可实现对直翼桨结构2.5 a以上的保护寿命。结论通过调整牺牲阳极设计参数,可对直翼桨桨叶、旋转箱体等关键结构提供较好的阴极保护效果,但旋转箱体与船体和上箱体的间隙由于结构遮挡效应保护不足,建议在实际工程应用中在这些结构部位表面涂装防腐涂料以降低腐蚀风险。

The work aims to investigate the influence of sacrificial anode design parameters on the cathodic protection ef-fectiveness of cycloidal propeller structures,so as to provide insights for the design and engineering applications of cathodic protection.A numerical simulation model based on the boundary element method was established for the structural analysis of cycloidal propellers used in ship propulsion systems.Cathodic protection simulation calculations were conducted,focusing on quantities,sizes,and arrangement positions of different sacrificial anodes.The study emphasized the cathodic protection poten-tial distribution on key structural components such as the upper-box,the rotating-box,blades,and blade end caps of cycloidal propellers,along with the estimation of sacrificial anode service life.Results indicated that increasing the quantity and size of sacrificial anodes made of Al-Zn-In-Mg-Ti aluminum alloy enhanced the cathodic protection effectiveness and extends the ser-vice life of sacrificial anodes.Changes in sacrificial anode arrangement positions impacted the potential gradient on blade sur-faces and altered the cathodic protection potential distribution of the cycloidal propeller structure.Employing 10 drop-shaped aluminum alloy sacrificial anodes sized at 0.18D×0.11D×0.04D(D was the diameter of cycloidal propeller),arranged in a single layer between blades,could achieve a protection lifespan of over 2.5 years for cycloidal propeller structures.Drawing upon the aforementioned discoveries,optimizing the design parameters of sacrificial anodes can significantly bolster cathodic protection for vital structures,including cycloidal propeller blades and rotating-box housings.Nonetheless,the structural shadowing effects in the gaps between the rotating-box housing and the hull and upper housing lead to inadequate protection.Therefore,it is ad-visable to implement corrosion-resistant coatings on these structural components during practical engineering applications to al-leviate corrosion risks.