Use of Computer Simulation Techniques to Assess Thrust Rating as a Means of Reducing Turbo-Jet Life Cycle Costs

Abstract

This paper investigates the concept of thrust rating as a means towards reducing the life cycle costs of turbo-jet engine ownership. Towards this end, the concepts of life usage and thrust rating will be discussed to provide a clear understanding of the goals and methods involved in this investigation. In general, all “serviceable” engines will experience varying levels of performance above baseline values. Thrust rating ideally seeks to limit engine performance to baseline values, thereby converting performance into life. In particular, this paper will present a general computer simulation technique that may be applied to any turbo-jet engine to quantify the life cycle savings resulting from the adoption of thrust rating techniques. The inter-relationships that exist between thrust rating and many practical in-service aspects of turbo-jet usage including performance degradation, operational roles and maintenance practices and policies will be investigated. Some strengths and limitations of the simulation technique will also be identified. This paper will discuss general guidelines for investigating the feasibility of performing thrust rating on various turbo-jet engines. While this technique is likely to be of greatest interest to users of high performance military turbo-jet engines, its principles can be adapted for other gas turbine uses.