Gas turbine development is constantly moving forward and for higher efficiency hotter turbine inlet temperature is required. Because of that, one of the largest design problems is to find efficient ways to cool the hot parts in the gas turbine.
The task was to develop and evaluate new alternative cooling and mounting concepts for a transition duct in Siemens latest gas turbine, SGT-750. Transition duct is a hot part and have the task to guide the hot gas from the combustion chamber to the turbine inlet in a gas turbine.
The transition duct of today is cooled by a relative large amount of compressor air which needs to be reduced in case of a power upgrade. The current mounting solution requires three combustion chambers to be removed for one transition duct maintenance, which is time consuming.
A literature study and a market research including patent searches was made to get an overview of solutions used today. Concept was then generated from function/means tree together with morphology matrixes. This was divided in two branches, one for cooling and one for mounting and sealing. The concepts were evaluated with Go-/no go screening, datum method and weighted objectives method. Further development and combination of the concepts led to different concept suggestions which will ease and shorten the maintenance and reduce the cooling air consumption with kept material temperature.
Source: Linköping University
Author: Öfverstedt, Tomas | Östberg, Johan