Wind Tunnel Measurements of a Multibladed Horizontal-Axis Small Wind Turbine

Heitor Andrade Porto,Carlos Fortulan,Arthur José Vieira Porto

doi:10.1590/jatm.v13.1231

Heitor Andrade Porto, Carlos Fortulan + Show 1 more

Open Access

https://doi.org/10.1590/jatm.v13.1231

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Abstract

This work experimentally investigates the effects that a different number of blades, three and five, has in the dynamic torque, acceleration, and power performance of a horizontal-axis small wind turbine. It presents the methodology used for calculating the temporal behavior of the aerodynamic torque generated by the blades during their acceleration phase. The tests were performed in an open section wind tunnel of 1.0 × 0.8 m. The model was produced by additive manufacturing and had two possible assemblies, with three and five blades. An in-line dynamic torque meter acquired the torque and angular speed data, and a National Instruments USB-6009 device processed the signal. The resistive torques were calculated by spin-down tests. The tests were executed at a wind speed of 10 m·s–1. The measurements displayed the five blades assembly having improved performance compared to the three blades: a higher static torque, which resulted in shorter stating time, and a power coefficient 39% higher.

Highlights

Small wind turbines (SWTs) are horizontal-axis or vertical-axis devices and, like their large counterparts, are mostly constructed with three blades
The Cp values are usually presented in a Cp vs. tip-speed ratio (TSR) curve, where TSR is the ratio between the blades tip-speed and the wind speed (Tummala et al 2016)
This work experimentally investigated the effects that a different number of blades have in a horizontal-axis SWT dynamic torque, acceleration, and power performance

Summary

Introduction

Small wind turbines (SWTs) are horizontal-axis or vertical-axis devices and, like their large counterparts, are mostly constructed with three blades. Their power potential is characterized by their power coefficient (Cp) value, which is the relation between the turbines power output and the power available at the wind. The maximum Cp value a wind turbine can achieve is 0.593 and it is denominated as the Betz limit (van Kuik et al 2015). Small wind turbines projects are bounded to energy harvesting. Proper wind resource assessment and suitable local energy tariffs are essential for a productive operation (Grieser et al 2015; Mithraratne 2009; Olsen and Preus 2015; Peacock et al 2008; Sunderland et al 2016)

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