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, the tertiary flow being in a tertiary flow vein radially external to said primary flow, delimited by an internal wall and an external wall;
• an air/oil type heat exchanger, arranged in the tertiary flow vein, wherein the heat exchanger comprises several angular sectors, each of the angular sectors comprising an oil inlet on the internal wall at an angular end of said sector, and an oil outlet on said internal wall at an opposite angular end of said sector, and wherein at least one of the angular sectors comprises a short-circuiting passage of said angular sector, extending fluidically between the oil inlet and the oil outlet along the internal wall;
• and
• structural arms extending radially in the tertiary flow vein at junctions between the sectors of the heat exchanger.