[Kenth]

The fuel is pushed up through the idle tubes, turns up in the nozzle, mixes with air from the upper air bleeds and goes down through the channel restrictions (economizers) and mixes with additional air from the side air bleeds if applicable and then down to the lower air bleeds/transition circuit to low speed and finally down to the holes for the idle mixing screw tips.
Some units also has idle bypass air drilled in the throttleplates.