Research On Key Technologies Of Water Injection Dredger

Dredger is an important tool in more and more modern dredgingprojects, but it is not suitable in some particular work environment, forexample, the relatively narrow deep grooves, pools, or a pipeline and theleveling work on the tunnel. In this case, we usually use the hydraulicdredging ship-water injection dredger (WID)-to complete the dredging work.WID is a dredging technique by which the sediment to be removed isfluidized through low-pressure injection of water into the bed. Uponfluidization, the mud flows as a density current away from the dredging site.This ship is suitable for small-scale projects. There are strict requirements ofits working environment, such as the sediment radius should be in thespecified range in the dredging location. It can greatly reduce the cost of theproject, have a good maneuverability in the work process, and not have muchimpact on the environment. The concept of water injection dredger was firstproposed by Van Wezenbeek, a Dutch engineer, and put it into production inthe1980s. In the late1990s, Chinese scholar also came up with using waterinjection dredger to complete the dredging work in Tongguan, Yellow River,and developed and constructed the five WIDs. Under this background，thepaper, also based on the research of water injection dredgers all around theworld, have done same analysis and research on conception design, shipmotion response in waves, flow resistance in pipelines, power equipmentselection and the dredging effectiveness of the water injection dredger.First of all, the paper came up with the latest design of WID withreference to Multi-purpose auxiliary vessels and the characteristics of the WID research at home and abroad, as well as the work environmentrequirements, including determination and optimization for principalcharacteristic of the main hull, design and fairing of fore and aft lines,general arrangement design, design of tank capacity and calculation of shipweight and center of gravity and so on. All these works aim at providing anobjective for the following detailed research. Then this article used theAQWA of the ANSYS module to analyze the movement of water injectiondredger in the waves, and gave the impact of the waves on the movement ofthe ship.The second focus of this article is to analyze the resistance loss inpipelines and the selection of the power equipment. Started from the nozzles,the paper use FLUENT to analyze the influence of flow assistance loss inpipelines by changing the shape, space and length of the nozzles, and gavethe ways to determine the nozzles parameters and power equipment. Thepaper researched on the resistance loss of the pipe, as well as the arrangementand optimization of the nozzles for water injection dredging, and providedthe theoretical guidance for the equipment configuration. To some extent, itdecreased the loss of overall energy consumption of the water injectiondredger.Finally, the paper illustrated the effects of sand erosion in different angleand lift height of the nozzles through the jet scour mechanism and sedimenttransport theory as well as the previous test. The economic andenvironmental impact of water injection dredger was also discussed in thispaper.