Gas Turbine Exhaust Systems: Design Considerations

The users of Gas Turbine powered equipment are very careful to ensure that they achieve their objectives in terms of power output and overall efficiency, but other important aspects of the system may be underspecified, and cause the user serviceability and maintenance problems during the systems planned operating life. One important area, crucial to reliable operation of the Gas Turbine, is the power turbine exhaust system. If particular care is not taken on the part of the user in specifying this component, he is likely to be provided with the minimum standard of equipment from the supplier. This paper highlights some of the areas that should be considered during the preparation of specifications, and in the evaluation of proposals. Specific problems of exhaust design will be addressed to assist the user to identify and question possible problem areas. The paper concludes that for minimal additional input during the initial stages of a project, long term cost savings could be made and that the overall system would be more reliable.