Underwater Dredging Device Suction Pipe Flow Field Analysis And Anti-blocking Method Research

In recent years,the siltation problem of lakes and reservoirs in China has become more and more serious.To solve the problem of dredging in deep water areas of rivers,lakes and reservoirs and holes in specific environments,Changsha Institute of Mining and Metallurgy has developed a self-propelled underwater dredging robot suitable for deep water and holes.Due to the specificity and complexity of the reservoir dredging system,the blockage phenomenon caused by the mismatch of operating conditions parameters may be caused during the dredging process,and this problem seriously affects the stability and efficiency of the underwater dredging system.Since the blockage cannot be observed visually during the underwater operation,it is important to simulate the flow characteristics of the mud two-phase flow in the suction pipe under different operating conditions.In this paper,the following elements are studied.(1)In order to obtain a more intuitive picture of the flow of slurry in the suction pipe and the movement law of sediment particles,the numerical simulation of mud two-phase flow is carried out by using the coupled CFD-DEM method based on DDPM,and the flow state,pressure and secondary flow characteristics of sediment particles in the suction pipe are shown intuitively.(2)In this paper,the reliability of the simulation is verified through the sediment dredging tests under different working conditions,and the sediment recovery rate is used to analyze the sediment collection at the entrance and exit of the suction pipe under different working conditions.The volume fraction of sediment collected under different working conditions is analyzed and the law that the volume fraction of sediment is negatively correlated with the reamer speed and positively correlated with the crawler traverse speed and mud pump power is obtained.(3)The method of adding clear water manifold to the mud suction pipe is proposed,and the orthogonal simulation table is established with the minimum flow speed of sediment particles as the anti-clogging index.The simulation results were subjected to extreme difference analysis,and suitable combinations of location parameters and working flow ratio conditions were obtained.The conclusions of the ANOVA method were verified using multi-factor sensitivity ANOVA,and a more detailed analysis of the significant effects of the main influencing factors was given.