Plasma Actuation Effect on a MW class Wind Turbine
Plasma Actuation Effect on a MW class Wind Turbine
复制标题
MW 级风力发电机上的等离子体驱动效应
DOI：
10.38036/jgpp.9.1_47
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Yukihiro Oryu
中科院分区：
文献类型：
--
作者：
H. Matsuda;Motofumi Tanaka;T. Osako;K. Yamazaki;N. Shimura;M. Asayama;Yukihiro Oryu
在1.75 MW磁场转子上进行了等离子体驱动技术的首次试验。在每个叶片的前缘表面安装了长度为8米的特制等离子体电极。在相同风速下，与等离子体关闭情况相比，等离子体打开情况下涡轮转速有所增加。入口风速直方图也显示出等离子体打开时入口风速比等离子体关闭时入口风速向更高速度区域偏移的趋势。利用模型涡轮的CFD分析定性地考察了等离子体驱动对这一特性的作用机理。因此，在测试期间，平均功率增加了4.9%。利用等离子体驱动技术进行前缘流动分离控制，即使在商业规模的大型风力涡轮机中，也有可能增加风力涡轮机的功率。由于自然风的波动，风力机叶片不断发生气流分离，导致风力机性能变差。叶片上流动的主动分离控制是降低风力涡轮机能源成本的最有效技术之一，因为它具有增加能量捕获和通过减少叶片负荷延长叶片寿命的潜力。非热介质阻挡放电（NTDBD）等离子体执行器是一种主动流量控制装置。该等离子体致动器与用于风力涡轮机叶片[1]上的流量控制的其他主动流量控制装置相比具有许多明显的优点。其优点如下：1. 可以诱导极薄射流（有效控制边界层流动）；它是全电动的，可以提供快速的响应时间。3 .不需要运动部件（运动部件总会带来机械故障）；它可以层叠到涡轮叶片表面（即使驱动器损坏也不会产生额外的阻力）。NTDBD等离子体致动器示意图如图1所示。等离子体致动器由由介电绝缘体隔开的薄电极组成。其中一个电极暴露在空气中，另一个电极被电介质材料完全覆盖。当向电极提供足够高的交流电压时，空气在暴露电极的角落边缘被电离，并扩散到覆盖电极的一个区域。这种电离流作为对周围空气的体力，导致致动器产生诱导的薄射流。当执行器工作在非定常模式（脉冲调制模式）时，对叶片分离流的控制效果最好（如[2-4]）。本文还报道了周期性振荡空气翼型[5]在非定常模式下等离子体驱动的有效性。利用JAXA研究组专门开发的高阶CFD方案，详细研究了等离子体驱动对分离流动控制的机理[6-9]。他们报道了非定常等离子体驱动对叶片边界层跨向涡的增强有一定的作用，这种增强的涡带来了有效的分离流动控制。在垂直轴风力机[10]和水平轴风力机[11]上研究了非定常等离子体对旋转叶片的驱动效应。Matsuda等人使用300w额定小型风力涡轮机进行风洞实验，该风力涡轮机的每个叶片的前缘都有等离子体致动器。通过改变进口风速，测量了等离子体打开和关闭两种情况下的涡轮转速。显然，与等离子体关闭情况相比，在等离子体打开情况下观察到涡轮速度的上升。报道了利用等离子体驱动提高风力发电机性能的可能性。基于这些有吸引力的结果，世界上第一次使用该等离子体驱动技术的现场测试使用了Mie大学30kW （Φ 10m）风力涡轮机[12]。利用无线局域网控制的监控摄像机固定在叶片根部，采用簇簇法进行了旋翼叶片流动的可视化试验。在叶片恒定转速为20转/分和固定偏航角的情况下，簇状流的行为清晰可见，而且很明显，这些分离流被这种技术非常有效地控制和抑制了[13]。试验结果表明，等离子体驱动有效地控制了前缘流动分离，在实际风况下也实现了风力机的转矩增大。覆盖电极裸露电极介电屏障放电
The first trial test for applying plasma actuation technology on a 1.75 MW field rotor was carried out. Specially developed plasma electrodes of 8 m in length were installed on the surface of the leading edge of each blade. An increase in turbine rotational speed has been identified for the plasma-on cases compared with the plasma-off cases for the same wind speed. Also, histogram of inlet wind speed showed a trend that inlet wind speed was shifted to higher speed region for the plasma-on case compared with the plasma-off case. The mechanism of plasma actuation on this behaviour was examined in qualitatively using CFD analysis of model turbine. Consequently, an averaged power increase of 4.9 % was achieved in the test period. Possibility of increase in wind turbine power even in a commercial scale large turbine has been proved by leading-edge flow separation control using the plasma actuation technology. INTRODUCTION Owing to fluctuated natural wind, wind turbine blade constantly suffered from flow separation, as a result wind turbine performance gets worsen. Active separation control of flow on the blade is one of the most effective techniques to reduce energy cost for wind turbines, since it has a potential both to increase energy captured and to extend blade life by reducing blade load. A non-thermal dielectric-barrier-discharged (NTDBD) plasma actuator is known as one of the active flow control device. The plasma actuator has a number of distinct advantages over other active flow control devices for flow control on the wind turbine blade [1]. Some of the advantages are as follows; 1. It can induce very thin jet flow (controls boundary layer flow efficiently), 2. It is fully electric and can provide fast response time, 3. It requires no moving parts (moving parts always brings mechanical troubles), and 4.It can laminate into the turbine blade surface (no additional drag force is generated even if the actuator is broken). Schematic view of the NTDBD plasma actuator is shown in Fig.1. The plasma actuator consists of thin electrodes separated by a dielectric insulator. One of the electrodes is exposed to the air and the other electrode is fully covered by a dielectric material. When a high enough A.C. voltage is supplied to the electrodes the air gets ionized at the corner edge of the exposed electrode and spreads out over a region of the covered electrode. This ionized flow serves as a body force on the ambient air and results in induced thin jet flow generates from the actuator. When the actuator was operated in unsteady mode (pulsed modulation mode), separated flow of the blade was controlled most effectively (e.g., [2-4]). Effectiveness of the plasma actuation operating in unsteady mode was also reported on a periodically oscillated air-foil [5]. The mechanisms of plasma actuation on separation flow control were studied in detail using specially developed high-order CFD scheme by JAXA’s group [6-9]. They reported that unsteady plasma actuation plays some role to strengthen the span-wise vortex in the blade boundary layer and this strengthened vortex brings effective separation flow control. The unsteady plasma actuation effect for rotating blade was studied both on a perpendicular axis wind turbine [10] and on a horizontal axis wind turbine [11]. Matsuda et al. carried out wind tunnel experiments using a 300 W rated small wind turbine having the plasma actuator located at the leading-edge of each of the turbine blade. By changing the inlet wind velocity, the turbine rotational speeds were measured for both the plasma-on case and the plasma-off case. Clearly the rise in turbine speed was observed for the plasma-on cases as compared to that for the plasma-off cases. The possibility of improving wind turbine performance using the plasma actuation was reported. Based on these attractive results, the world first field test with this plasma actuation technology was carried out using Mie University 30kW (Φ 10m) wind turbine [12]. Visualization test of rotor blade flow was also carried out using tuft method with wireless-LAN controlled monitoring camera fixed at the blade root. Under constant blade rotational speed of 20 rpm and fixed yaw angle, tuft behaviour was clearly visualized and it became clear that these separation flows were controlled and suppressed very effectively by this technique [13]. These test results infer that leading-edge flow separations were effectively controlled by the plasma actuation and torque augmentation in wind turbine was realized even under real wind conditions. Covered electrode Bare electrode Dielectric Barrie discharge
DOI：
10.2514/6.2010-5090
发表时间：
2010-06
期刊：
--
影响因子：
--
作者：
K. Asada;K. Fujii
通讯作者：
K. Asada;K. Fujii
DBD 等离子体致动器对动态失速中的俯仰翼型进行分离流控制
DOI：
--
发表时间：
2018
期刊：
影响因子：
--
作者：
K. Mitsuo;H. Fukumoto;H. Kato;T. Atobe;S. Watanabe;A. Oyama;T. Nonomura;H. Aono and K. Fujii
通讯作者：
H. Aono and K. Fujii