波浪能捕获浮体对能量转化系统特性的影响

Influence of Floating Body on Performance of Wave Energy Conversion System

振荡浮体式波浪能捕获系统中浮体设计是能量捕获的关键。浮体水动力模拟研究中功率输出多假设为线性阻尼,对于波浪能液压转化采用非线性输出阻尼更切合实际。针对垂荡浮体液压转化系统,建立不规则波作用下垂荡圆柱浮体非线性动力学模型和非线性液压能量转化系统模型,研究圆柱浮体直径和入水深度对浮体运动响应、液压转化系统动态特性和总特性的影响。随着圆柱直径在一定范围内增大,不规则波浪力、液压缸输出力、浮体运动响应、捕获和输出功率的动态峰值显著增加,捕获功率和捕获效率、马达输出功率和转速接近线性增加;随着圆柱入水深度在一定范围内增大,波浪力呈线性减小,液压缸输出力、捕获功率和捕获效率均缓慢上升到最高点然后逐渐下降。浮体直径和入水深度对液压转化效率影响比较小。研究成果为波浪能捕获液压系统浮体设计提供理论依据。

Floating body design is the key to energy capture in an oscillating body wave energy capture system.The power output of floating body is often assumed as linear damping in hydrodynamic study.It is more suitable to adopt nonlinear output damping for the hydraulic wave energy conversion.For a heave body hydraulic conversion system,the non-linear dynamic model of the heave body under irregular waves and the non-linear hydraulic conversion system model are established.The influences of cylinder diameter and draft on the motion response of floating body,the dynamic performance and overall characters of hydraulic conversion system are investigated.As the cylinder diameter increases in a certain range,the peak values of irregular wave exciting force,hydraulic cylinder output force,floating body motion response,energy capture and power output all increase significantly,and the mean values of energy capture,capture efficiency,motor power output and speed increase nearly linearly.With the increase of draft in a certain range,the wave exciting force decreases linearly,and hydraulic cylinder output force,energy capture and capture efficiency slowly increase to the maximum then decrease gradually.The cylinder diameter and draft have little effect on hydraulic conversion efficiency.The research results provide a theoretical basis for floating body design of wave energy capture hydraulic system.