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Component erosion in gas turbines can be a serious problem. The erosive particles which may be sand, ingested into compressors in desert regions, or carbon shed from gas turbine combustors, contribute to significant blade life reduction. In extreme cases, both sand and carbon particles can cause surface build up on turbine blades reducing efficiency and block the small diameter cooling holes thereby reducing cooling effectiveness. A two-dimensional turbine cascade tunnel was designed and built incorporating perspex rotor blades which were eroded for a variety of parametric conditions. The aerodynamic performance of the turbine cascade tunnel is examined with respect to pressure losses and efficiency. The introduction of film cooling air in varying quantities and configurations in the leading edge region is shown to significantly reduce erosive wear. Maximum erosion was found to occur close to the stagnation point on the suction surface of the aerofoils. The test Reynolds number and particle trajectories were chosen to closely represent the entry conditions of an actual film cooled turbine which had experienced this type of erosive wear in operation.

The problem of pressure ripple propagation in fluid filled pipelines has been understood for a long time. To-date, however, mathematical representations of pressure ripple standing waves generated in hydraulic systems have been limited to very simple systems operating at low mean pressure levels and over limited frequency ranges. This report details the evaluation and development of the mathematical impedance representation of hydraulic systems and system components. With the result that these can be used to predict, with confidence, pressure ripple levels in hydraulic circuits under normal conditions of operation and over a wide frequency range. The confidence comes from the detailed practical examination of the pressure ripple levels created in hydraulic systems, made up from standard hydraulic components, operated under normal conditions of pressure and flow. Although the test circuits used are only representative of practical systems, they do not perform any specific function, they incorporate all the major features of circuit design, including branch lines and impedances (components) in series. Lastly, the ability to model with accuracy the pressure ripple levels within a hydraulic circuit provides the means by which they can become part of the overall design specification for a hydraulic system. This thesis illustrates the difficulties which restrict the practical implementation of this ideal.