Triple-flow axial turbomachine comprising a diverging heat exchanger in the third flow

An axial turbomachine, comprising:

• a first separation nozzle capable of separating an incoming air flow into a radially internal air flow and a radially external air flow, called secondary flow;
• a second separation nozzle capable of separating the radially internal air flow into a primary flow and a tertiary flow in a tertiary flow vein radially external to said primary flow;
• and
• a heat exchanger disposed in the tertiary flow vein, wherein said tertiary flow vein is annular and circumferentially continuous over 360° around a longitudinal axis of the turbomachine;
• wherein the turbomachine comprises a stator traversed by the tertiary flow and arranged upstream of the heat exchanger, said stator being configured to straighten said tertiary flow, the heat exchanger extends radially and axially only within a divergent longitudinal section of an upstream section of the tertiary flow vein, said tertiary flow vein comprising a downstream section having a converging longitudinal section, following the tertiary flow.