Adaptive Polynomial Chaos for Gas Turbine Compression Systems Performance Analysis

Abstract

The design of a gas turbine, or one of its constituent modules, is generally approached with some specific operating
\ncondition in mind (its design point). Unfortunately, engine components seldom exactly meet their specifications and
\ndo not operate at just one condition, but over a range of power settings. This simplification can then lead to a product
\nthat exhibits performance worse than nominal in real-world conditions. The integration of some consideration of
\nrobustness as an active part of the design process can allow products less sensitive to the presence of the noise factors
\ncommonly found in real-world environments to be obtained. To become routinely used as a design tool, minimization
\nof the time required for robustness analysis is paramount. In this study, a nonintrusive polynomial chaos formulation
\nis used to evaluate the variability in the performance of a generic modular-core compression system for a three-spool
\nmodern gas turbine engine subject to uncertain operating conditions with a defined probability density function. The
\nstandard orthogonal polynomials from the Askey scheme are replaced by a set of orthonormal polynomials
\ncalculated relative to the specific probability density function, improving the convergence of the method.