Turbojet engine outlet lobe mixer with guiding protrusions, and method of mixing airflows

The invention aims at providing a sufficient air exchange in the engine area without raising the static pressure in the outlet area of the air exchange duct. In order to do this, the invention provides for an outlet section capable of concentrating the outlet of the exchange airflow towards zones with smaller static pressure. A turbojet engine outlet according to the invention provides an engine cowl, which comprises an external wall of a circumferential duct in which circulates an exchange airflow of the turbines, and an airflow mixer. At the outlet, the duct delivers the exchange airflow towards the mixer for the primary and secondary airflows of the turbojet engine. The mixer presents hot and cold lobes. In particular, the engine outlet also includes guiding of the exchange airflow towards the cold lobes.