Improving VAWT performance through parametric studies of rotor design configurations using computational fluid dynamics

Abstract

Vertical axis wind turbines present several advantages over the horizontal axis machines that make them suitable to a variety of wind conditions. However, due to the complexity of vertical axis wind turbine (VAWT) aerodynamics, available literature on VAWT performance in steady and turbulent wind conditions is limited. This paper aims to numerically predict the performance of a 5 kW VAWT under steady wind conditions through computational fluid dynamics modeling by varying turbine configuration parameters. Two-dimensional VAWT models using a cambered blade (1.5%) were created with open field boundary extents. Turbine configuration parameters studied include blade mounting position, blade fixing angle, and rotor solidity. Baseline case with peak Cp of 0.31 at tip-speed ratio of 4 has the following parameters: mounting position at 0.5c, zero fixing angle, and three blades (solidity = 0.3). Independent parametric studies were carried out and results show that a blade mounting position of 0.7c from the leading edge produces the best performance with maximum Cp = 0.315 while the worst case is a mounting position of 0.15c with peak Cp = 0.273. Fixing angle study reveals a toe-out setting of −1° producing the best performance with peak Cp of 0.315 and the worst setting at toe-in of 1.5° with peak Cp of 0.287. The solidity study resulted in the best case of four blades (solidity = 0.4) with peak Cp = 0.316 and the worst case of two blades (solidity = 0.2) with peak Cp = 0.283.