Originally Posted by Shawn Coyle
Acceleration rate is also dictated by the surge margin of the engine, which has something to do with the compressor design, but I'm not exactly sure what it has to do with it!
This is due to the pressure ratio / flowrate performance of the compressor, Shawn. As you put more fuel in the higher combustion chamber temp causes higher expansion, and thus high pressures. If increased slowly the engine speed increases mass flowrate, so pressure change is not a problem. I increased too quickly the pressure can cause reduced flow, until the compressor stalls. This sets a limit on dRPM/dt.
With FADEC controllers i imagine the main limitation on rate of increase of fuel mass flow rate is Turbine Entry Temperature.
Mart