The Gas turbine Simulation Program GSP, a component based modelling environment, is NLR’s primary tool for gas turbine engine performance analysis. 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 MS-Windows. Gas turbine configurations are simulated by establishing a specific arrangement of engine component models in a model window (view an example model window).
GSP is a generic modelling tool capable of modelling virtually any gas turbine engine configuration including (external) loads (like water breaks, pumps, generators, etc). GSP is primarily based on 0D-modelling (zero-D) of the thermodynamic cycle of the gas turbine. This implies that the flow properties are averaged over the flow cross section areas at the interface surfaces of the component models (inlet and the exit). GSP utilizes component model stacking to create the thermodynamic cycle of the engine of interest. Input of the model configuration is the cycle design, or any known reference point (or preferably several points) of a new engine. Information needed for the cycle configuration, eg. turbine and compressor maps, is readily available from the manufacturer or from the internet (e.g. manufacturer fact sheets, ASME papers, etc.).
Besides being a performance prediction tool, GSP is especially suitable for parameter sensitivity analysis such as: ambient (flight) condition effects analysis, installation (losses) effects analysis, analysis of effects of certain engine malfunctioning (including control system malfunctioning) and component deterioration effects analysis. Input for the analysis is based on the model configuration (e.g. fuel flow can be specified to calculate the generated power, or when the fuel flow is set as a state variable the power can be specified to calculate the corresponding fuel flow). By running the simulation, output data set in the component property window will be displayed in a table, which can be visualized by a build-in graph tool. Data available includes the gas conditions (temperatures, pressures, mass flows, areas, speeds, etc) and the gas composition (gas species are available since GSP uses a full Thermo-chemical gas properties model). The simulation results can be exported to tab separated files, which can then be used for custom analysis (e.g. comparison of simulation data to running equipment measured data).
The development of GSP started at the Delft Technical University (TUD, Aerospace dept.) in 1986. At TUD, NASA's DYNGEN (NASA TN D-7901, 1975) program was used for jet- and turbofan engine simulation. However, DYNGEN appeared to have many problems with numerical stability and had a poor user interface. As a consequence, GSP was developed, inheriting features from DYNGEN. Significant deficiencies of DYNGEN were fixed in GSP; especially the stability, the speed of the numerical iteration processes and the user interface were improved. It appeared that an additional amount of improvements, adjustments and extensions to the GSP program were necessary before useful simulation of a generic jet engine was possible. Development continued at NLR, where GSP has been converted first to FORTRAN77 and later when desktop computers gained computational power for acceptable prices to Borland® Delphi(TM). Delphi allows rapid adaptation due to the use of object orientation, offering excellent means to maintain and extend the program.
GSP's most interesting features are listed below