Off-design simulations deal with the behavior of a gas turbine with given geometry. This geometry is found by running a single cycle design point.
To prepare for an off-design simulation at first the component design points must be correlated with the component maps. This can be done automatically using the standard maps of GasTurb and the standard design point settings in these maps. The maps will be scaled before the off-design calculation commences in such a way, that they are consistent with the cycle design point.
This approach works well if one is interested mainly in the basic off-design behavior of an engine type. However, if more accurate simulations of a specific engine are desired, then special compressor and turbine maps should be used.
GasTurb allows replacing the standard maps with maps that are more representative for the gas turbine being simulated. A component map collection with many compressor and turbine maps, ready to be used with GasTurb, is available. Moreover, there are the programs Smooth C and Smooth T on offer which make the preparation of compressor respectively turbine maps for performance simulation programs easy and accurate.