Fluctuating loads on a tidal turbine due to velocity shear and turbulence: Comparison of CFD with field data
Fluctuating loads on a tidal turbine due to velocity shear and turbulence: Comparison of CFD with field data
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DOI：
10.1016/j.renene.2017.05.048
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发表时间：
2017-11-01
期刊：
影响因子：
8.7
通讯作者：
Stansby, P. K.
中科院分区：
文献类型：
--
作者：
Ahmed, U.;Apsley, D. D.;Stansby, P. K.
潮汐涡轮机上的波动载荷对于疲劳分析很重要，并且全尺寸条件下可用的信息或模拟有限。在这里，计算流体动力学模拟已经进行了几何解析的全尺寸潮汐流涡轮机，并与实验数据进行了比较，从1兆瓦的机器部署在EMEC测试现场。最初，使用代表现场但低入流湍流的入流平均速度剖面进行了雷诺平均纳维尔-斯托克斯（RANS）和大涡模拟（LES）。两种紊流闭合的平均叶片压力相似，并产生与测量值相当的平均功率系数。然后，为了模拟湍流对载荷的影响，采用了在入口处设定合成湍流的LES。对于这些模拟，平均速度，雷诺应力和长度尺度的流入剖面是从前驱通道流模拟确定的，具有额外的应力和长度尺度因子，以匹配现场测量的轮毂高度条件。推力、功率和叶片弯矩的波动周期性地产生于起始平均速度剪切和支撑塔的阻塞效应，以及叶片产生的湍流、接近流湍流和波浪的连续谱范围。LES模拟与现实的入流湍流令人满意地再现了相对频谱分布的叶片弯曲力矩在低波条件。(C)2017爱思唯尔有限公司版权所有
Fluctuating loads on tidal turbines are important for fatigue analysis and there is limited information or simulation available for full-scale conditions. Here, CFD simulations have been performed for a geometry-resolved full-scale tidal-stream turbine and compared with experimental data from a 1 MW machine deployed at the EMEC test site. Initially, Reynolds-averaged Navier-Stokes (RANS) and large eddy simulations (LES) were performed using an inflow mean velocity profile representative of the site but low inflow turbulence. Mean blade pressures were similar for the two types of turbulence closure and yielded mean power coefficients comparable with measurements. Then, to simulate the effect of turbulence on loads, LES with synthetic turbulence prescribed at inlet was employed. For these simulations, inflow profiles of mean velocity, Reynolds stresses and length scales were determined from a precursor channel-flow simulation, with additional factoring of stresses and length scales to match hub-height conditions measured on site. Fluctuations in thrust, power and blade bending moment arise cyclically from onset mean velocity shear and the blocking effect of the support tower and over continuous spectral ranges from blade-generated turbulence, approach-flow turbulence and waves. LES simulations with realistic inflow turbulence satisfactorily reproduced the relative spectral distribution of blade bending moments in low-wave conditions. (C) 2017 Elsevier Ltd. All rights reserved.