An Experimental Study of Horizontal Axis Wind Turbine Performance in Artificial Natural Wind by an Active Control Multi-Fan Turbulent Wind Tunnel

Abstract

Abstract Recent developments in wind turbine design research account for the effects of velocity fluctuation and the characteristic turbulence of the installation location site to improve performance. For the design, a low-cost natural wind generator and a laboratory-based performance evaluation of the wind turbine are useful. This paper describes a new actively controlled multi-fan wind tunnel that generates natural wind at a reduced cost. The driving section of its wind tunnel has 100 PC cooling fans that are controlled by an original embedded system. The fluctuating velocity wind is successfully generated with a mean velocity 7m/s, turbulent intensity 2% and turbulent integral scale 5 m, 10 m, 20 m, based on Karman’s power spectrum density function. In particular, the wind satisfies the Kolmogorov’s −5/3 multiplication rule of inertial subrange with the frequency range 0.01∼2.0 Hz. Furthermore, the performance of a wind turbine in steady and natural winds can be investigated. From the results, it is made clear that integral scale has a large effect on the wind turbine performance. The maximum power coefficient in natural wind of the integral scale 5 m and 10m is 124% larger than one of steady wind with the same mean velocity 7 m/s.