Air-oil heat exchanger comprising divergent parietal channels

An air/oil heat exchanger, comprising:

• a radially internal wall,
• a radially external wall, and
• a plurality of partitions, some of the partitions are hollow and through which oil passes, the partitions, the radially internal wall, and the radially external wall are delimiting corridors, among which internal parietal corridors and/or external parietal corridors delimited by the radially internal and/or external walls and the adjoining partitions, and central corridors at a distance from the radially internal wall and the radially external wall and delimited only by the partitions, each corridor allowing air flow to pass through the air/oil heat exchanger, wherein the internal parietal corridors and/or the external parietal corridors each define a radial height that increases monotonically from an entrance of the air/oil heat exchanger to an exit of the air/oil heat exchanger, and wherein each of the central corridors defines a central corridor radial height that is maintained constant or decreases from the entrance to the exit.