This paper describes a project undertaken by most first-year Engineering undergraduates at Lancaster University in which they are required to design, build and test a scale-model wind turbine.
Working in pairs, the students are able to make design decisions on the blade geometry and the number of blades on the turbine. Utilising fused-deposition modelling (FDM) additive-manufacturing (AM) technology, students are now able to produce their turbine blades by additive manufacture, which has provided an opportunity to greatly improve the accuracy and finish of the model aerofoils that students can produce, as well as ensuring geometric repeatability of blades on the same hub. It also allows students the capability to produce concave surfaces on the underside of their blades, which was almost impossible when producing the blades by hand methods.
The performance of the model turbines fabricated using the AM technique has been noticeably better than that of models produced by hand, the previous method. Introducing the AM method has also given an extra educational dimension to this design-build-test project.
In this project, students learn about aerofoils and simple aerodynamics and mechanics. The project introduces them to testing and measurement methods, as well as to the advantages and limitations of the particular AM technology used. For testing, the model turbine is mounted in a wind tunnel on a simple dynamometer, allowing different levels of torque to be applied and the speed of rotation to be measured, for a variety of air speeds. Students are encouraged to plot dimensionless performance curves of power coefficient against blade-tip-speed ratio. Using these figures, they can then predict the performance of a full-size rotor with similar geometry.