A METHODOLOGY TO ASSESS DESIGN UNCERTAINTY IN SELECTING AFFORDABLE GAS TURBINE TECHNOLOGY

A design consideration that typically has not been addressed in propulsion technology advancements is a systematic accounting of risk and uncertainty. Although this probabilistic concept of design was suggested by Timson 25 years ago, no widespread evidence of usage has been noted to date. Failure to account for uncertainty can result in significant shortcomings in performance when the engine is initially tested. Assessment of risk should consider typical performance issues such as specific fuel consumption (sfc) but also account for cost and weight. Addressing uncertainty will require a culture change for most propulsion component designers and technologists, who typically address component performance improvement as a discrete value or level, rather than a distribution of possible performance outcomes. A methodology is discussed that allows quantification of uncertainty in the gas turbine design and analysis process. The methodology can be employed to rank order the cost effectiveness of advanced component technologies or alternatively can be used to determine probable performance (sfc and thrust) of engines that have component performance uncertainties. Execution of the methodology requires a desktop computer and commercially available software.