| At present,due to the use of fossil energy in the world,energy depletion and environmental pollution problems are becoming more and more serious,for this reason,countries around the world are paying more and more attention to various new energy sources.As a new energy source,wave energy,with the advantages of abundant reserves,wide distribution,high energy flow density,clean and sustainable,its development and utilization technology has been increasingly valued by coastal countries.Among the existing wave energy conversion technologies,point absorption wave energy conversion technology has become a research hotspot in the field of wave energy utilization because of its simple structure,high conversion efficiency,high reliability and low manufacturing cost.The buoy-chain-sprocket wave energy collection device studied by our group belongs to the oscillating buoy type wave energy conversion technology,which has good application prospects due to its advantages of good reliability and high cost performance.For the need of subsequent prototype structure optimization and control,this paper conducts an in-depth study on the hydrodynamic performance of the floating body sprocket wave energy device based on the open source CFD tool OpenFOAM,and the main research contents are as follows:(1)Based on the open-source CFD software OpenFOAM,the numerical water tank is preset using C++,the wave-making and wave-dissipation modules are invoked,the reasonable grid size and time step are determined,the numerical water tank for the physical model experimental water tank is created,and the reliability of the numerical water tank wave-making is verified by comparing the wave-making effect between the numerical water tank and the actual water tank.(2)The buoy-chain-sprocket wave energy collection device has the characteristics of twodegree-of-freedom motion under regular waves,one-way wave energy collection characteristics and constant damping force/constant recoil force characteristics.To this end,the open source CFD software OpenFOAM is used to define the point constraint at the center of the ball-hinged sub,to realize the oscillation of the guide bar around the ball-hinged sub by using the point constraint,to create the guide bar by defining two variables anchorPosition and centerOfMass,and to restrict the relative movement between the floating body and the guide bar only by using the line constraint,so as to The two-degree-of-freedom motion characteristic of the floating body moving along the guide bar and swinging longitudinally with the guide bar under the regular wave is realized.The lineSpring module is installed at the bottom center of the floating body and its movable end is tied to the center of the ball-hinged sub,and the internal tension of the lineSpring module is set according to the moving direction of the floating body relative to the guide bar:when the moving direction of the floating body relative to the guide bar is away from the ball-hinged sub,it is equal to the constant damping force,and when the moving direction of the floating body relative to the guide bar is toward the ball-hinged sub,it is equal to the constant chain-receiving force,so as to achieve One-way wave energy acquisition characteristics and constant damping force/constant chain force dynamic characteristics of the device.(3)Based on the open source CFD software OpenFOAM,we select the appropriate wave theory according to the actual situation of the physical model experiment,complete the threedimensional modeling of the floating body model,and use the overlapping mesh technology to complete the simulation calculation of the hydrodynamic performance of the physical model experiment by using the key technology in(2),and compare the calculation results with the actual test results of the hydrodynamic performance of the physical model experiment to verify the reliability of the hydrodynamic The reliability of the simulation technique is verified.(4)The hydrodynamic simulation technology developed in this paper is used to complete the hydrodynamic simulation of the prototype of the buoy-chain-sprocket waveenergy collection device by combining the wave conditions in the experimental sea area,and the performance parameters(constant take-up force and constant damping force)of the prototype of the buoy-chain-sprocket wave energy collection device are optimized with the highest capture width ratio as the optimization target,which provides the theoretical basis for the subsequent development and control of the prototype.Using the hydrodynamic simulation technology developed in this paper,the hydrodynamic simulation of the prototype of the buoy-chain-sprocket wave energy collection device is completed by combining the wave conditions of the experimental sea area,and the performance parameters(constant retracting force and constant damping force)of the prototype of the buoychain-sprocket wave energy collection device are optimized with the highest capture width ratio as the optimization target,which provides the theoretical basis for the subsequent development and control of the prototype. |
