Effect of Reynolds Number on Performance of Contra-Rotating Propeller Wind Turbines

Abstract

In recent years, growing concern over global warming caused by the use of fossil fuels has led to a demand for clean power generation that can be used semi-permanently and is environmentally friendly. Wind power generation is expected as the development of new energy sources accelerates. Propeller wind turbines are widespread for large wind turbines. On the other hand, a wide variety exists for small wind turbines. Among them, the authors consider that 1kW wind power generation is important for the spread of small wind turbines, and are focusing on contra-rotating propeller wind turbines, which are expected to achieve high power. In this research, we aim to increase the power of a small wind turbine by installing a wind collecting device suitable for a contra-rotating propeller. However, the aerodynamic characteristics of a contra-rotating propeller inside a hollow structure have not been clarified. In addition, small wind turbines are operated under low Reynolds number conditions, and change in Reynolds number due to fluctuation in wind speed are expected to have a significant effect on performance. In this paper, the effect of Reynolds number on the performance of a contra-rotating propeller wind turbine is investigated by numerical flow analysis using a model with a contra-rotating propeller installed in the pipe.