TY  - JOUR
AU  - LI, Jialong
AU  - Chen, Yongcan
AU  - LI, Yonglong
AU  - WANG, Haoran
AU  - XIE, Hui
PY  - 2023
TI  - Design and detection efficiency analysis of desilting replacement module in sediment accumulation environment
JO  - Journal of Tsinghua University (Science and Technology)
SN  - 1000-0054
SP  - 1104
EP  - 1112
VL  - 63
IS  - 7
AB  - ObjectiveThe drainage and energy dissipation building is an important aspect of the water conservation and hydropower project, and its structural safety is linked to the safety of the whole project. For a long time, the drainage and energy dissipation buildings have been subjected to the erosion of high pressure and high speed water, which will inevitably cause damage to the concrete structure. The apparent damage to underwater concrete structures is concealed due to the structure's uniqueness and diversity. The traditional method of diver inspection or manual inspection following cofferdam draining takes a long time and is expensive and dangerous. Using underwater robots for unmanned inspection reduces personal risk. However, the underwater robots' detection accuracy is limited due to the sediment accumulation on the bottom and poor visibility in the water, which makes it impossible to conduct timely investigations of defects and hidden dangers. This study has developed a desilting replacement module that is suitable for the conditions of sediment bottom and turbidity water and studied the mechanism design of the module, the efficiency of silt removal, and defect detection.MethodsThe desilting replacement module is built in this study by examining the starting condition of sediment deposition and the features of the submerged water jet. It consists mostly of the desilting mechanism, the replacement detection mechanism, and the lifting mechanism. The Euler multiphase flow model was used to create the continuity equation and momentum equation of water and sand, and the hydrodynamic influence of the desilting replacement module was investigated. A simulation model based on Euler water-sand two-phase flow was developed using computational fluid dynamics software to mimic the desilting detection process of the desilting replacement module in the underwater sediment environment. The thickness of the sediment is considered to be 100 mm in the simulation, and the height of the sediment deposited at the beginning distance of the replacement detection shell was used as a variable to evaluate the status of the desilting replacement module when the detection effectiveness is optimal. Finally, the simulation findings are compared and examined by combining them with the real experimental data.ResultsThis study verified the necessity of each mechanism in the desilting replacement module and concluded that when the initial height of sediment from the bottom of the replacement detection shell was 60 mm, the desilting detection efficiency was the highest, and the sediment of 100 mm thickness in the detection area could be removed to the remaining 10% within 1.56 s, and the total time of "desilting and detection" was 9.56 s.ConclusionsThe silt removal replacement module's novel design tackles the underwater detection problems caused by underwater sediment accumulation and turbidity. The desilting replacement module may be carried on most existing underwater detection robots, which can significantly improve the detection ability of underwater robots in turbidity water environments. It can achieve short-term efficient single point or long-term continuous visual image acquisition in the sediment environment, depending on the operation requirements, which has a great promotion role for the application of underwater robot detection technology in the water conservation and hydropower industries.
UR  - https://doi.org/10.16511/j.cnki.qhdxxb.2023.26.004
DO  - 10.16511/j.cnki.qhdxxb.2023.26.004