| The transportation of marine oil and gas is inseparable from the pipeline.Submarine Jet Trencher is the key equipment in the marine oil and gas transportation project.It is mainly used for trenching and pipe laying operations on the seabed to ensure the safety and stability of submarine pipelines.Based on the existing prototype and design experience of trenching and pipe laying equipment at home and abroad,this paper designed a submarine pipeline jet trencher for burying pipe with a diameter of one meter,studied the overall scheme of submarine jet trencher and made analysis with water jet breaking.The performance index and technical requirements of the submarine pipeline jet trencher were clarified,and the overall scheme design of the jet trencher was completed.The mechanical system components of the jet trencher body and the layout of each mechanical structure were determined.According to the working environment and functional requirements of the hydraulic system,the spatial position scheme and compensation scheme of the hydraulic system of the trencher are determined.The design of the hydraulic system was carried out,and the key components in the hydraulic system were selected and calculated.According to the jet method of the water jet nozzle and the applicable conditions of the jet,the nozzle of the trencher was chosen.The flooding jet flow field of three continuous direct jet nozzles was numerically simulated by FLUENT software.The axial jet velocity and radial pressure on the jet action surface of the three nozzles were compared and analyzed.The flow field structure of the jetting nozzle jet,the mechanism of breaking the soil and the criterion of determination were determined.The parameters of the water jet nozzle and the selection of the pump were selected based on the soil quality and design indicators.The research methods of water jet breaking soil were compared.Based on ALE algorithm,the LS-DYNA software was used to simulate the jet breaking of the nozzle of the trencher;The cross-sectional shape of the crater formed by the nozzle jet breaking soil was obtained by simulation,and the variation of soil stress and crater depth during the process of water jet breaking was analyzed.The development trend of the crater depth with the jet action time was studied;The influence of jet flow velocity and nozzle diameter on the soil-breaking effect of water jet is studied in detail,which provides a reference for the selection of nozzleparameters of trencher nozzle.Based on the overall mechanical structure design scheme,according to the working requirements of the trencher,the structural design of the structural components such as the traveling device,the frame,the spray arm and the suction and sludge discharge device in the trencher was carried out.The flow of fluid inside the suction pipe was simulated by Flunet software.The flow characteristics of the suction pipe and its variation with the radius of curvature of the suction pipe were studied.The resistance loss in the suction tube of four different radii of curvature was chosen for the radius of curvature of the suction tube. |
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