Load Deflection Characteristics of Guide Vane End Seals

This Master Thesis consider the load deflection characteristics of end seals incorporated in guide vanes used in hydropower turbines. The force response of the end seals is critical in order to prevent leakage and thus increase the efficiency of the turbine. The guide vanes is located in front of the turbine runner in order to regulate the flow of water. At present time, either one or two O-rings, cut into mouldings, is used as these aforementioned end seals. Rainpower, which have proposed this master thesis only have a selection of experimental measurements of the load characteristics for a limited amount of geometries and material parameters of the end seals. By use of two dimensional modelling and Finite Element Analysis focusing on groove tolerances, cross-sectional dimensions, and material properties, a parameter study of situations including both one and two sealing elements is assessed. ABAQUS 6.14-1 is used for construction of two dimensional models and conducting Finite Element Analysis of the sealing elements. Interaction properties such as contact algorithm and frictional behaviour are taken into consideration. In addition, procedure notes, additional results, proposed test data guide lines for experimental material testing of elastomers and early model development is presented in appendices. It was concluded that; using a linear-elastic material approach is sufficient to recreate the trends of the material behaviour in highly confined environments. Several load deflection curves were carried out and compared, the results indicated distinctive material trends depending on the aforementioned factors. However, experimental test data of different material batches are required to implement numerical analysis with hyperelastic properties in ABAQUS. Relevant theory, methodology and results is considered in addition to evaluation and discussion of results. Recommendations for any further work have also been proposed