| As a renewable new energy,large-scale commercial application of wind energy has become the general trend.In recent years,wind power technology has developed rapidly and has become an important means to help achieve the goal of "double carbon".As the development of inland and FOWT is nearly perfect,domestic and foreign research has focused on the deep sea.The floating platform with excellent hydrodynamic performance is becoming more and more important for the fan.Barge FOWT has the advantages of low cost,simple structure and reliable performance.Adding air cushion at the bottom is expected to further improve its hydrodynamic performance,especially stability.Aiming at the design scheme of annular multi compartment air cushion platform of a 5MW wind turbine,an efficient seakeeping motion prediction model is developed,and the effectiveness of the numerical algorithm is verified by the model test results;On this basis,taking the optimal stability and minimum seakeeping motion response of the platform as the optimization objectives,the scheme of annular multi compartment air cushion platform is optimized based on the optimization algorithm NSGA-Ⅱ.Firstly,based on the Extended Boundary Element Method,a simplified motion model of a single air tank air cushion platform is established.In this method,the radiation velocity potential caused by the pulsating pressure of the air cushion is regarded as the extension of the radiation potential of the six degree of freedom motion of the floating body,the radiation potential and hydrodynamic coefficient of the floating body are calculated by the zero speed Green’s function method,and the aerodynamic coefficient is calculated by the ideal gas state equation;The calculation model in this paper is used to predict the motion response of box single air chamber air cushion platform,and compared with the test results in the literature to verify the accuracy of the motion model of air cushion platform deduced in this paper.Secondly,based on the motion model of single air chamber air cushion platform,the motion model of annular multi compartment floating fan air cushion platform in mooring state is deduced and established,and the water tank seakeeping model test of annular multi compartment floating fan air cushion platform is carried out.Through the comparison between the numerical calculation results and the real water tank model test results,The validity of the motion model of the annular multi compartment air cushion platform deduced in this paper is verified.Finally,the parametric model of the annular multi compartment floating fan air cushion platform is established,the key design parameters are extracted as the optimization object,and the hydrodynamic optimization model of the annular multi compartment floating fan air cushion platform is established based on the optimization algorithm NSGA-Ⅱ.The model is used to study the influence of different design parameters on the static stability and irregular wave motion response of the platform,and then optimize the design of the platform.Finally,the optimization model design scheme suitable for different levels of offshore sea conditions in China is obtained.Compared with the original design scheme of the platform,the recovery torque of the optimized design scheme obtained in this paper increases by 6.18% at an inclination of 10°,and the meaningful value of motion response(root mean square of 1 / 3meaningful value of motion response in each direction of fan unit position)under level IV,V and VI sea conditions decreases by 46.25%,43.6% and 36.3% respectively,In other words,compared with the original scheme,the optimized platform design scheme has significantly improved the stability and seakeeping performance under common offshore sea conditions in China. |
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