SAE AS5571

This document provides standards for several aspects of aero-thermal system 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 standards are derived from NPSS common practice. NPSS was chosen because it is an available product. The standards described 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 that 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 standards previously existed for object-oriented models. This initial version as an aerospace standard supersedes ARP5571, which was a recommended practice for over 15 years. This is sufficient time for most suppliers to have become compliant with this document as a standard. This document is also more applicable to current technology than its Fortran predecessors and so requires higher recognition as a standard. Finally, due to the widespread use of object-oriented modeling, making this document a standard will help it to be more easily enforceable, both for contract purposes and business internal standards.