The S61 IGV, which are fuel pressure activated, close at plus 63% ng to brinf the airflow into line with the 3 rows of movable stators which follow the row of IGV's. The primary reason being to allow the smoother transition of air into the compressor at low compressor rotation speeds. As the Ng increases the IGV's close up bringing the IGV's and Stators into line with the 7 stages after the front 3. Without this system the ECU would be damn difficult to start. Any Questions there????
Right let me get this straight, you are saying that the IGVs are closing as Ng increases. So your glorious mass flow is being obstructed by your now closed IGVs at high power?
Heat by the way is the kinetic energy of the gas particles. It is that kinetic energy that is imparted on the power turbine blades (via conservation of momentum) that generates this power. Have you never wondered why your crewmen don't see the 600 degrees C that you T5 gauges are reading? It is because the power turbine has cooled your T5 and transferred that energy to the gearbox.