Experimental Study of a Reference Model Vertical-Axis Cross-Flow Turbine
Experimental Study of a Reference Model Vertical-Axis Cross-Flow Turbine
复制标题
参考模型垂直轴贯流式水轮机的试验研究
作者：
P. Bachant;M. Wosnik;B. Gunawan;V. Neary
美国能源部参考模型垂直轴贯流涡轮机的1：6比例模型（直径1.075 m）的机械功率、总转子阻力和近尾流速度在拖曳水池中进行了实验测量，为验证数值模型提供了全面的开放数据集。通过改变转子的角速度和拖架速度，分别在一系列叶尖速比和多个雷诺数下测量性能。在叶尖速比λ0 = 3.1时，观察到峰值功率系数CP = 0.37，旋翼阻力系数CD = 0.84。在涡轮机直径雷诺数ReD ≥ 106的情况下，观察到功率系数的弱线性Re相关性。通过在NACA 0021转子的支柱上覆盖圆柱体，研究了支柱阻力对涡轮机性能的影响。正如预期的那样，这种修改大大降低了转子功率系数。还测量了NACA 0021和圆柱形构型（去掉转子叶片）的支柱阻力损失。对于λ = λ0，在下游1 m（x/D = 0.93）处测量尾流速度。将平均速度、湍流动能和平均动能输送与用相同试验装置获得的高稠度涡轮机的结果进行了比较。与高实度情况一样，平均垂直平流被计算为近尾流恢复的最大贡献者。然而，总体而言，RM 2情况下计算出的流向尾流恢复水平较低-这是相对较低的实度和锥形叶片减少叶尖涡脱落的结果-负责平均垂直平流-以及较高的工作叶尖速比引起的湍流水平较低，因此减少了动态失速。数据集、处理和可视化代码以及涡轮机的CAD模型已经公开。
The mechanical power, total rotor drag, and near-wake velocity of a 1:6 scale model (1.075 m diameter) of the US Department of Energy’s Reference Model vertical-axis cross-flow turbine were measured experimentally in a towing tank, to provide a comprehensive open dataset for validating numerical models. Performance was measured for a range of tip speed ratios and at multiple Reynolds numbers by varying the rotor’s angular velocity and tow carriage speed, respectively. A peak power coefficient CP = 0.37 and rotor drag coefficient CD = 0.84 were observed at a tip speed ratio λ0 = 3.1. A regime of weak linear Re-dependence of the power coefficient was observed above a turbine diameter Reynolds number ReD ≈ 106. The effects of support strut drag on turbine performance were investigated by covering the rotor’s NACA 0021 struts with cylinders. As expected, this modification drastically reduced the rotor power coefficient. Strut drag losses were also measured for the NACA 0021 and cylindrical configurations with the rotor blades removed. For λ = λ0, wake velocity was measured at 1 m (x/D = 0.93) downstream. Mean velocity, turbulence kinetic energy, and mean kinetic energy transport were compared with results from a high solidity turbine acquired with the same test apparatus. Like the high solidity case, mean vertical advection was calculated to be the largest contributor to near-wake recovery. However, overall, lower levels of streamwise wake recovery were calculated for the RM2 case—a consequence of both the relatively low solidity and tapered blades reducing blade tip vortex shedding—responsible for mean vertical advection—and lower levels of turbulence caused by higher operating tip speed ratio and therefore reduced dynamic stall. Datasets, code for processing and visualization, and a CAD model of the turbine have been made publicly available.