Additive manufacturing radically changes the design process giving unprecedented freedom of design and enabling a step change in part performance.
The general idea of selecting appropriate candidates within the Alstom hot gas parts portfolio is described in this paper. The strategy as used in the selection process is to identify parts with either a high (internal) complexity or to choose parts with a high number of sub-parts and the necessary high number of assembly steps, which are needed with the current manufacturing methods (e.g. precision casting or weld assemblies).
The current reheat burner front panel of the heavy duty gas turbine is today produced from three metal layers. The layer facing the hot gas contains the complex near-wall cooling channel system. The metal sheet facing the cold side features the acoustic damping volumes. An intermediate metal sheet separated the two systems. Brazing is used to assemble the sup parts into the final front panel. With the identified strategy to use additive manufacturing, the design is adapted to allow the production of a single component that includes all the functionality and avoids heavy machining and assembly steps.
The paper focuses on the design changes and challenges that were required and observed during the adaption of the GT26 (Rating 2011 onwards) reheat burner front panel. Also the necessary adaptions of the qualification process and the lifetime assessments are described in detail.
Finally, the additive manufacturing version of the reheat burner front panel was subjected to a heavy duty test program. Engine tests were completed. The disassembled SLM component was found in excellent condition. Subsequent material investigations have confirmed the good part condition from a metallurgical point of view.