I read that the bleed flow negatively affects the thrust levels for a turbofan engine. However, I was wondering if vice-versa is true as well? Whenever the thrust levels for a turbofan are lowered at the same conditions, does the bleed flow value also decrease? What practically happens in an engine?
Bleed air pressure is not directly linked to the passenger cabin.
Bleed air is used to power air cycle machines which provide cabin pressurization and temperature control. The bleed air supply is regulated so that a minimum constant supply is maintained over a wide variety of engine operating parameters.
Bleed air is also often used in other aircraft systems. Wing anti-ice, engine anti-ice, and engine starting are 3 more common uses.
On some aircraft, selecting engine anti-ice will automatically increase the flight idle speed to insure an adequate minimum bleed air pressure reaches the engine inlets.