Immersion acoustic positioning method of corrosion for large tank bottom plate

In order to avoid detection dead zone in corrosion detection of large ̄scale storage tank floorꎬ an immersion acoustic method is proposedꎬ of which locating corrosion sound source is a key. Based on a passive source localization algorithm featuring time delay estimation and considering characteristics of immersed acoustic detection of tank floorꎬ a mobile planar five ̄element cross array acoustic method was applied to simulate positioning of bottom plate and verify the test. The results show that this method meets the requirement of corrosion detection in accuracy of direction finding and distance measurement. Direction finding accuracy is not affected by sound source angle φ and distance r while distance accuracy is only positively related to r and independent of φ. With the fitting relationship between relative error of distance and r obtained from experimentꎬ the maximum effective radius of immersed acoustic detecting unit can be 中 国 安 全 科 学 学 报 China Safety Science Journal 第30卷 2020年 determined.