Gasturbine simulation with GSP is based on non-dimensional (or zero-dimensional) modelling of the processes in the different gasturbine components with aero-thermodynamic relations and steady state characteristics ("component maps"). With zero-dimensional modelling, air and gas properties, thermodynamically averaged over the flow cross-areas (in and exit per component module), are used in the calculations.
A gas turbine model is created by arranging ("stacking") different predefined components (like inlet, compressors, combustors, turbines and exhaust nozzles) in a configuration corresponding to the specific gasturbine type to be simulated. The exit gas condition of a component then forms the inlet gas condition of the next component in the configuration.
The processes in gasturbine components are determined by relations among 2 up to 5 parameters defined by component maps and thermodynamic equations. These parameters are air or gas properties and other parameters such as rotor speeds and efficiencies determining the component operating point.
GSP is an "off-design" model. A predefined design point (it should be called reference point, as it is a point that is used for reference for the off-design analyses, it is not necessarily an actual design point; usually the take-off or cruise is used for reference) is calculated first from a set of user specified design point data. The deviation from the design point is calculated by solving a set of non-linear differential equations. The equations are determined by the mass balance, the heat balance, the equation for conservation of momentum and the power (energy) balance for all components.
In case of a transient simulation, the differential equations include time-derivatives. Then, in each time step, dynamic effects are calculated and the solution represents a quasi-steady state operating point.
Modelling approach
