Lopez N., Mara B., Mercado B., Mercado L., Pascual J., 2015, Characterisation of the Effects of Surface Modifications to Flow Across Rotating Cylinders using ANSYS CFD Modelling, Chemical Engineering Transactions, 45, 1129-1134.
Past and present studies have proven that rotating cylinders can generate significantly higher lift forces compared to airfoils. This force may be used to drive a wind generator for energy conversion and pollution reduction. Such, called a Magnus turbine, operates with low cut-in wind speeds, making it promising for urban power generation. Also, its self-stalling capability makes it safer to operate at strong wind speeds. However, the significant drag forces which accompany it have to be minimized. Analysing the whole system, one opportunity to improve its performance is to apply different surface modifications on the cylindrical rotor. In this study, a screening design of experiment was implemented to characterize the effects of different surface modifications to the lift and drag forces generated on a rotating cylinder. The experiments were run using the computational fluid dynamics simulation software ANSYS CFX. Results indicate that the effects demonstrate an exponential increase in drag reduction as the speed ratio is increased. The most significant reduction in drag comes from roughening the surface of the cylinder at high speed ratios while using bumps at lower speed ratios. Lastly, changing a regular to a frustum cylinder provides the most increase in lift. This study should provide leads for further research and inspire other process applications.
