Production Process for Tunnel Modeling : An Analysis of Composites for Water Applications

Sammanfattning: Hydroelectric power is a leading source of renewable energy where large turbines convert the kinetic energy of water into electricity. In order to not exceed the capacity limit of the turbine, excess water in the dams needs to be diverted away through spillways. In order to do in-house testing of the water flow, a 1:30 scale tunnel manufactured by an external supplier is used. The production of the tunnels is however preferred to be done in-house. In this thesis different material options and methods for the tunnel modeling production are examined. This has been achieved by a thorough literature study following practical experiments. Polymers are known for their strength and stiffness to weight ratio as well as low cost and availability. To further enhance its material properties for given applications, polymers can be reinforced with different fibers creating a composite. Several fibers were considered, however in order to support the set strategy of Vattenfall AB regarding environmental and sustainability goals, natural fibers, specifically hemp and flax deemed to be a good fit using epoxy as the matrix material. Based on the material properties tested for the composites, flax with epoxy was the resulting material used to model the tunnels. The final method for the production process using said material was based on three different methods that were tested. The conclusion was that using a flax-epoxy composite with a hand lay-up method using a negative mold made of Styrofoam gave the best results. It should, however, be noted that a definite production process for the tunnel could not be determined due to time limitations. A theoretical production process for tunnel modeling was nevertheless composed.