Design and manufacturing study of hydroelectric turbines using recycled and natural fiber composites

Graduation date: 2014The objective of this project is to demonstrate the feasibility fiber-reinforced turbine components through a design and manufacturing study. The motivation for using composites is to reduce weight and simplify manufacturing especially at high production volumes. In addition, natural fiber composites are implemented for applicable components to reduce environmental impact. Existing steel designs provided by major manufacturers are used as models. These are re-designed using composite materials, maintaining original geometry as much as possible. The components selected for composite design are the turbine penstock, scroll case, guide vanes, runner (impeller) and draft tube. In addition, the design of a composite fish ladder is presented to show the application of composites to other elements of hydroelectric power. Once the structural and mechanical design was complete, material and manufacturing costs were analyzed. The choice of materials was based upon loading requirements, the runner required a high strength random reinforcement carbon fiber sheet molding compound (SMC) while a glass fabric and rovings provided adequate strength for the guide vanes, scroll case, penstock and outer walls of the fish ladder while minimizing the cost. A flax fabric was selected for the design of the draft tube additionally using a bio-based PLA resin. The inner sections of the fish ladder use a flax fabric and polypropylene pultrusion.\ud Manufacturing methods for each were selected based on geometry and cost. The complex shape of the runner was most easily formed using compression molding, which also reduced the cost as compared to hand lay up. A comparison between hand lay up and vacuum infusion was completed for the guide vanes and scroll case. Hand lay up was chosen for the draft tube as it is the most commercially proven method for the manufacture of components using natural fibers. Filament winding, the method used for the penstock would be the ideal method of manufacture but it has yet to be completed in a commercial setting with natural fibers.\ud Results show the cost of most parts is dominated by tooling (molds) for the components as the research focused on a small run of ten parts, assumed to be for research and testing purposes. However, the contribution of tooling can be cut in half if the run size is doubled. The design and manufacturing analysis does support the use of composite materials in hydroelectric turbines and the costs associated with their manufacture are within reasonable parameters for industry