Lost Thrust Methodology for Gas Turbine Engine Performance Analysis

Abstract

This paper presents and evaluates a lost thrust method for analysis of thermodynamic performance in gas turbine engines. This method is based on the definition of a hypothetical ideal engine that is used as a point of comparison to evaluate performance of the real engine. Specifically, component loss is quantified in terms of decrements in thrust of the real engine relative to the ideal engine having the same design point cycle. These lost thrust decrements provide a basis for accurately evaluating the performance cost of component losses while simultaneously accounting for all component interactions. The analysis algorithm is formally developed in detail and is then demonstrated for a typical separate flow turbofan engine. Various scenarios are examined and the results of these exercises are used to draw conclusions regarding the strengths and weaknesses of this approach to gas turbine performance analysis.