The bleed air drives a motor. That drives the HP spool. It doesn't cool the turbine.
I didnīt say it does.
When you say the compressor is deactivated are you talking about SURGE bleed valves and VSVs?
SURGE bleed open.
The word 'pumping' that you are using. Do you mean a surge, compressor stall or are you talking about 'hunting' ?
Your word "hunting" describes the matter the best.
I.E. The rotor accelerating and then decelerating before reaching self sustaining speed?
I donīt get that point.
I think much of the above must be lost in translation as I can't understand a word of it.
Study it for 3 Years and then try to explain this topic without using "Grade of reaction" and "Smith diagramme". I am trying my best.
Greetings,