Research On Shallow Water Mooring System Design Of Floating Wave Energy Platform

With the continuous development of the world economy,in the process of transforming agricultural civilization to industrial civilization,fossil fuels,as the blood of civilization development,have gradually become one of the factors restricting the high-quality growth of economic civilization due to environmental pollution and energy shortage.As the focus of national development,island development energy supply has long been plagued by problems such as being remote from land and difficult to supply,so there is a great demand for safe,reliable,and easy to maintain clean energy.In the South China Sea islands and reefs area,there are long-term problems such as frequent typhoons in shallow water and the low bearing capacity of coral reef foundations.In addition,under the harsh environment of shallow water,excessive instantaneous mooring tension will lead to the stability of wave energy platform and the obvious decrease of typhoon self-existence,resulting in frequent deanchoring and anchor chain fracture.Since most of the working areas of the platform are sea areas with high wave energy flow density,it is necessary to improve the ability of the platform to resist wave impact.In view of the above problems,according to the actual engineering requirements,the shallow water mooring system characteristics of floating wave energy platform under coral reef geology in the South China Sea are studied based on the clear hydrodynamic performance of the wave energy platform.The main contents are as follows: Based on the potential flow theory,the frequency domain hydrodynamic characteristics of the floating wave energy platform are studied by using the hydrodynamic analysis software AQWA,which provides the calculation basis for the time domain analysis of the mooring system.Based on the wind,wave,and current parameters of the launching sea area,the following schemes are preliminarily designed and damaged: the full anchor chain scheme,the full anchor chain + buoy scheme,the elastic cable scheme,and the elastic cable + buoy scheme.On this basis,a Z-shaped mooring scheme with the combination of buoy blocks is designed.In order to reduce the ultimate load of mooring,reduce the possibility of mooring line failure and de-anchoring,the pre-tension,anchor chain diameter,mooring line angle,buoy block spacing,and weight are taken as the optimization sensitive parameters,and the ’ Z ’ mooring scheme is optimized.The main conclusions are as follows: with the increase of incident wave height,the influence of impact load on shallow water mooring system is enhanced,and the influence is different under different incident angles.Due to the uniform force,the motion displacement space of the platform is large,and the impact load on the platform is the smallest under 45° incidence,which is insensitive to the change of wave height.Compared with the full anchor chain scheme,the addition of buoys can effectively reduce the mooring load and the range of platform motion,but in the harsh environment of the typhoon,the mooring limit load will increase under some wave directions.Compared with the full anchor chain scheme,the elastic cable addition can effectively reduce the mooring load,but it will increase the platform displacement,and the combined application of elastic cable and buoy can limit the platform displacement based on maintaining the reduction of ultimate load.Compared with the full anchor chain scheme,the ’ Z-shaped ’ mooring scheme can effectively reduce the mooring load,limit the motion range of the platform,and reduce the possibility of anchoring and anchoring.Due to the gravity adjustment device,it is also convenient for towing construction.This scheme provides a reference for the design of a mooring system in shallow water harsh environment.