Aircraft propulsion system comprising an aft pylon fairing with lateral walls that are profiled for injecting cool air along a thermal protection floor

Propulsion system for an aircraft, comprising a bypass turbojet engine and a pylon intended to attach the turbojet engine to an airframe of an aircraft, the pylon comprising an aft fairing comprising two lateral walls and a floor to protect the pylon from the heat of a primary flow ducted by a jetpipe of the turbojet engine,

• the floor comprising two lateral floor portions positioned one on either side of a mid-plane of the aft fairing and separated from the jetpipe so that the lateral floor portions with the jetpipe respectively delimit two air passage spaces which are open laterally and towards the rear of the propulsion system,
• and wherein each of the lateral walls of the aft fairing comprises, at its end facing the jetpipe, a lateral wall portion which extends rearwards and towards the mid-plane and which delimits one of the air passage spaces.