This document provides recommendations for several aspects of air-breathing gas turbine engine performance modeling using object-oriented programming systems. Nomenclature, application program interface, and user interface are addressed with the emphasis on nomenclature. The Numerical Propulsion System Simulation (NPSS) modeling environment is frequently used in this document as an archetype. Many of the recommendations for standards are derived from NPSS standards. NPSS was chosen because it is an available product. The practices recommended herein may be applied to other object-oriented systems.
While this document applies broadly to any gas turbine engine, the great majority of engine performance computer programs have historically been written for aircraft propulsion systems. Aircraft and propulsion terminology and examples appear throughout.
Gas turbine engine manufacturers (suppliers) have long provided their customers with computer programs which simulate engine performance. Application manufacturers and others (customers) use these programs, often called models or simulations, in design studies, mission analysis, life cycle analysis, and performance prediction of their products. These models are used throughout the life of a product, from conceptual design through production, deployment, field use, maintenance, and overhaul. Communication between suppliers and customers is more productive and less error prone if all engine models adhere to common guidelines with respect to presentation of data and interface with other computer programs. No guidelines or recommended practices previously existed for Object-Oriented models.
Revision A has been created to correct minor typographical errors as well as address integer switch values that have been added in Appendix A, also some revisions were made in the Program Status Indication section.
Revision B introduces additional object naming at the process level, as well as addressing the concept of higher-level model structure exercising multiple component simulations (Assemblies).