NLR’s primary tool for gas turbine engine performance analysis is the ‘Gas turbine Simulation Program’ (GSP), a component based modeling environment. GSP’s flexible object-oriented architecture allows steady-state and transient simulation of any gas turbine configuration using a user-friendly drag&drop interface with on-line help running under Windows95/98/NT. GSP has been used for a variety of applications such as various types of off-design performance analysis, emission calculations, control system design and diagnostics of both aircraft and industrial gas turbines. More advanced applications include analysis of recuperated turboshaft engine performance, lift-fan STOVL propulsion systems, control logic validation and analysis of thermal load calculation for hot section life consumption modeling. In this paper the GSP modeling system and object-oriented architecture are described. Examples of applications for both aircraft and industrial gas turbine performance analysis are presented.

Real-time simulation of gas turbine engine performance is used in a variety of aerospace applications. For simulation of propulsion system performance in flight-simulators, fidelity requirements become increasingly stringent. Significant improvements in simulation fidelity can be obtained when using thermodynamic models instead of the customary (piece-wise) linear real-time models. However, real-time thermodynamic models require sophisticated methods to efficiently solve the model equations on a real-time basis with sufficient speed. NLR has developed the ‘Turbine Engine Real-Time Simulator’ (TERTS) generic real-time engine simulation environment for full thermodynamic simulation of various gas turbine engine configurations. At NLR’s National Simulator Facility (NSF), research is performed on pilot-in-the-loop simulation of complex aircraft and helicopter configurations such as thrust-vectoring and Integrated Flight Propulsion Control (IFPC) concepts. For this application, high-fidelity real-time gas turbine models are required. TERTS has an efficient method for solving the engine model equations real-time. The system is implemented in Matlab-Simulink®, which offers advantages in terms of control system modeling flexibility. With TERTS, detailed thermodynamic real-time engine models can easily be implemented in NSF providing an excellent means to analyze a variety of engine effects on pilot-in-the-loop aircraft performance. In this paper the TERTS modeling environment will be described including the numerical solutions used to comply with the real-time requirements. A TERTS model of a military afterburning turbofan will be presented including simulation results.

A method to predict gas turbine component life based on analysis of engine performance is presented. Engine performance history is obtained from in-flight monitored engine parameters and flight conditions and downloaded for processing by a tool integrating a number of software tools and models. These subsequently include a comprehensive thermodynamical engine system model, heat transfer, thermal and mechanical load models, and finally, a life consumption model. Thermal and mechanical load distributions in the component as well as component life can be predicted. At this stage, the overall life prediction inaccuracy of the tool is dominated by the relatively high inaccuracy of the lifing model, and therefore, component life can only be predicted relative to a reference life. The tool is demonstrated with an analysis of the F100-PW-220 engine 3rd stage turbine rotor blade life consumption during a recorded RNLAF F-16 mission. Using the engine system model with a detailed control system, deterioration effects on engine performance were analyzed and the effect of engine deterioration on blade life consumption rate was determined. The tool has significant potential to enhance on-condition maintenance and optimize aircraft operational use.