串联式振荡水翼的纵向间距对获能的影响

Influence of the longitudinal spacing of tandem oscillating hydrofoils on power extraction

振荡翼式水流能发电装置近年来受到能源领域的关注,水翼的运动参数和排列方式对获能功率有着重要影响。为分析串联式振荡水翼的纵向间距对获能的影响,寻找最优获能规律,基于开源计算流体软件OpenFOAM,采用动网格技术对前后串联振荡双翼的获能情况进行了研究。发现当翼间总体相位差在π/2附近时,双翼装置的总体获能效率达到最大,约为53.3%;为进一步提升双翼装置的获能,改变上下游振荡水翼平衡位置的纵向间距,形成上、下游两翼错位排列,当两水翼竖直方向平衡位置间距处于3.5倍弦长时,后翼的获能效率可达45.3%,获能表现显著提升;当错位排列时,前翼的尾涡在经过后翼时,改变了后翼涡脱落的时间点和位置,影响了后翼表面的压力分布,从而使升力与升沉运动间的同步性更佳,提升了获能。上、下游两翼错位排列布置对串联式振荡水翼产生的获能提高有积极作用。

In recent years,the oscillating hydrofoil power generation device has attracted much attention in the energy field.The motion parameters and arrangements of the hydrofoils have an essential impact on power extraction.To analyze the influence of longitudinal spacing of tandem oscillating hydrofoils on power extraction and find the optimal power extraction region,based on an open source computational fluid software OpenFOAM,the dynamic mesh technology was applied to study the performances of tandem oscillating hydrofoils.It is found that when the global phase between the dual hydrofoils is about π/2,the total energy harvesting efficiency reaches the maximum value,about 53.3%.To further improve the power extraction of the system,the longitudinal spacing of the balanced position between the upstream and downstream oscillating hydrofoils was changed to form an interlaced arrangement.When the balanced position spacing of the dual hydrofoils is 3.5 times the chord length,the power extraction efficiency of the downstream hydrofoil can reach up to 45.3%,and the performance of power extraction is significantly improved.When the hydrofoils are interlaced,the trailing vortex of the upstream hydrofoil changes the time and position of vortex shedding on the downstream hydrofoil,which affects the distribution of pressure on the surface of the downstream hydrofoil.And this effect improves the synchronization of lift and heave motion which has a beneficial impact on power extraction.The interlaced arrangement of the dual hydrofoils has a positive effect on the power extraction of tandem oscillating hydrofoils.