弹簧刚度对嵌入式振荡水柱波能装置水动力性能的影响

Effects of spring stiffness on hydrodynamics of nested oscillating water column wave energy device

提出嵌入方箱式防波堤的垂荡式振荡水柱(OWC)波能装置,利用开源计算流体动力学库OpenFOAM及工具箱waves2foam,对该波能装置的能量转换效率和水动力特性开展数值研究.采用流体体积法(VOF)捕捉气液界面,利用Rigid-Body Dynamic网格技术求解垂荡运动.在不同入射波频下,探究垂直线性弹簧约束(用无量纲弹簧刚度表示)对OWC波能装置的波能转换效率、反射系数、透射系数、能量耗散系数、相对压降、有效相对振荡幅度和相位差等的影响.结果表明,结构物适当的垂荡运动有利于提升OWC装置在特定频率条件下的波能转换效率;振荡水柱和结构物间的运动相位差是决定能量转换效率的关键因素;为了提升能量转换效率,调节结构物的垂荡运动来控制相位差的措施是可行的.

A heave-only oscillating water column(OWC)wave energy device integrated in box-type breakwater was proposed.Using the open-source computational fluid dynamics platform OpenFOAM and toolbox waves2foam,the energy conversion efficiency and hydrodynamic properties of the wave energy device were investigated numerically.Fluid volume method(VOF)was used to capture gas-liquid interface and Rigid-Body Dynamic grid technology was employed to solve the heave motion.The effects of vertical linear spring restraints(expressed by dimensionless spring stiffness)on the wave energy conversion efficiency,reflection coefficient,transmission coefficient,energy dissipation coefficient,relative pressure drop,effective relative oscillation amplitude and phase difference of the OWC wave energy device under different incident wave frequencies were explored.Results show that the proper heave motion of the structure is conducive to improving the wave energy conversion efficiency of the OWC device at a specific frequency range.The motion phase difference between the oscillating water column and the structure is the key factor to determine the energy conversion efficiency.It is feasible to improve the wave energy conversion efficiency by controlling the phase difference with adjusting the heave motion of the structure.