扑翼式潮流能装置水动力学性能与能量摄取机理研究

Compared to the traditional turbines, the pitching-hydrofoil-type tidal-stream-energy converter has the advantages of higher converting efficiency, easiness of installed capacity expansion, better adaption of shallow water and less impact to ship channels and ocean environments. Its engineering feasibility has also been proved by the sea trials of prototype devices. Former studies have little experimental data support and the prescribed numerical model can not predict the accurate results because of too many simplifying assumptions. Therefore, former studies could not reveal the dynamic and power take-off characteristics, and are hard to provide sufficient supports to the development of the device. The present study aims at the engineering development of the device, takes the pitching hydrofoil as the main subject. The fully & semi-passive pitching & heaving motions and power take-off mechanism of the hydrofoil under various incident flow conditions are investigated in the experimental studies. The experimental studies also provide validation data to the fully-passive unsteady numerical model, which will be established based on the CFD software. The relationship between the flow structures & vortex shedding characteristics and the dynamic responses of the hydrofoil will be studied numerically. Effects of the controlling strategies, including the fully passive, semi-passive and fully positive motions, electrical loads and the system damping on the hydrodynamic performance of the hydrofoil will be studied. The power take-off mechanism will be revealed, and the optimization of the system within various strategies will be conducted, which will provide concrete theoretical basis to the practical development of the pitching-hydrofoil type tidal-stream-energy converter.

扑翼式潮流能装置相比于传统水轮式机构，具有能量转换效率高、易于扩容、浅水适应性强、对航道与生态环境影响小等优点，海试装置已证明其可行性，因而开发潜力巨大。早期的传统研究没有试验数据支持，数值计算以强迫运动形式为主，且由于过多简化假设导致无法准确反映装置的运动特性与能量转换规律，难以为装置设计开发提供支持。本项目以扑翼式潮流能装置的工程开发诉求为出发点，以扑翼机构作为主要研究对象，通过水工物理模型试验考察水翼在不同来流条件下的自由升沉振荡、控制升沉振荡、能量输出变化等参量，辨识遴选关键设计参数。基于CFD软件构建全瞬态非定常数值模拟模型，考察水翼周围流场变化、涡脱落规律与其流固耦合运动响应之间的关系。全面比较全被动式、半被动式、全主动式控制策略及后端负载与系统阻尼对装置水动力学特性的影响，揭示该类装置的能量摄取机理，优化机构型式参量与控制策略，为扑翼式潮流能装置实用化开发奠定理论基础。

扑翼式潮流能装置利用其多自由度运动从流动中捕获能量，该装置具有额定转速较低，对环境及生物影响较小，对流速及水深要求小等优点，其获能性能与传统的轮机式获能装置相当。因此，扑翼式潮流能装置在潮流能开发等领域具有一定的应用前景及优势。本项目以扑翼式潮流能装置为主要研究对象，采用物理模型试验及数值模拟相结合的方法，对其水动力学性能及获能机理进行了系统的研究。.本项目分别考察比较了升沉-俯仰型与耦合俯仰型扑翼在均匀流及剪切流条件下的获能及稳定性能。研究发现，在均匀流中升沉-俯仰型扑翼的获能性能优于耦合俯仰型扑翼，而在剪切流中耦合俯仰型扑翼的获能性能及稳定性能均优于升沉-俯仰型扑翼。本项目在多种控制策略下对扑翼进行试验及数值模拟研究。全主动控制扑翼研究得到了扑翼动力性能及获能性能随俯仰幅度的分布规律。半主动控制扑翼的研究揭示了俯仰幅度及阻尼对扑翼动力响应及获能性能的影响规律。本项目开展了双扑翼试验及数值模拟研究，给出了副俯仰幅度、折减频率、阻尼系数、转动惯量及扑翼间距的最佳设计值，分析了双扑翼的耦合作用及其对系统获能性能的影响。本项目采用主动形变及被动形变对柔性翼进行了数值模拟研究。研究考察了形变区域、形变相位、形变系数、阻尼系数及弹性模量等对柔性翼获能性能的影响规律及作用机理，识别出有助于获能性能优化提升的形变参数。.在项目资助下，共发表高水平论文12篇，其中SCI期刊论文11篇，会议论文1篇，已投稿SCI期刊论文2篇。项目取得了预期的原创性成果，完成了相关考核指标要求。.本项目构建的扑翼试验系统及数值模型，可实现多种控制策略并且具有高度的扩展性，可满足多方面研究需求，是国内在扑翼式潮流能装置领域首次系统性探索，填补我国在该领域技术及研究方面的不足。本项目研究成果具有较高的理论价值及实际应用前景。