| Currently,the global population is increasing and the demand for high quality seafood is growing as the standard of living improves and there is a more urgent need to obtain high quality protein.The ocean,also known as the water breadbasket,has always been our source of quality seafood,but in the last three decades the quantity and quality of fish have been greatly affected by overfishing and marine environmental pollution.So more scholars put their eyes on the development and utilization of marine deep-water aquaculture,and it has become a general consensus that fishery aquaculture gradually develops from traditional fence aquaculture to offshore deep sea.High-density polyethylene(HDPE)gravity deepwater nets are greatly restricted in draft depth and wind and wave resistance,the main structure of all-steel truss structure nets is easy to corrode,and the mixed structure of floating body and truss nets are limited in working sea area due to their draft depth.And the marine engineering type net frame compound structure net tank combines multiple structural forms and combines them in a certain way,which solves the defects existing in the other three types of structures,ensures the safety of the breeding target and solves the real deep-sea ecological breeding needs.This paper is based on SolidWorks and CFD analysis software.Strength calibration and coupling analysis are carried out for the designed deep-sea nets,the corresponding support data are obtained through tidal current observation experiments,and the force effects of deep-sea nets under various working conditions are analyzed and put into the sea in Shengsi to verify,and the main research contents are as follows.1.Consult the relevant standard documents,make the selection according to the design guidelines of the net box,select the structure according to the wave height data and hydrographic conditions of the working sea of the net box design,verify the selection of the net box material by the wave flow field assumption method and the concentrated mass method.Through the analysis of the working environment of the net box,the floating frame system and the net clothing system are determined,and the positioning mooring method is determined by combining with the geological drilling samples of the seabed.The main structure of the net tank,such as column,shell,support material and truss material,is selected by dimensional calculation.2.Using SolidWorks software to model the main structure of the net tank,apply the equilibrium method,energy method and dynamic method phase,design and check the main components according to the relevant standard documents,and design the sacrificial anode protection device considering the high corrosiveness of the marine environment.Simulation analysis software is applied to fully consider the three aspects of sea wind,wave and current load on the structure mechanics,and the analysis results are obtained.3.The CFD software STAR-CCM+ was selected for the coupling analysis of the nets,and the correct relaxation factor and Coulomb number were chosen to define the solver,and the corresponding physical model of the nets was set up.The analysis data were obtained from the temporary observation points set up in Shengsi sea area,and many parameters were obtained from my observation records,which were real and reliable.The tidal characteristic values were counted using the tidal observation technique.The four tidal observation points were divided into six observation layers from the surface to the bottom,and the statistics of the measured maximum flow velocity during the small and large tides were carried out respectively.The data were analyzed reasonably by using the tidal tide and residual flow analysis method,and the perfect data of the stations were taken for the analysis of the net box to verify the rationality of the design.In this paper,the overall net design of deep-sea nets is carried out according to the work condition analysis,combined with the numerical simulation study on the flow field distribution of nets,and the influence of currents and other factors on nets is determined according to the tidal observation experiments,and the net strength calibration is carried out,which provides theoretical,experimental and simulation support for the study of the design technology of deep-sea nets. |
