Triple-flow axial turbomachine comprising a diverging heat exchanger in the third flow
An axial turbomachine includes a first separation nozzle capable of separating an incoming air flow into a radially internal air flow and a radially external air flow, called a 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 the primary flow, delimited by an internal wall and an external wall; and an air/oil type heat exchanger, disposed in the tertiary flow vein. The heat exchanger includes several angular sectors, each angular sector including an oil inlet on the internal wall at an angular end of the sector, and an oil outlet on the internal wall at an opposite angular end of the sector.
1 . 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.
2 . The axial turbomachine according to claim 1 , wherein each of the angular sectors of the heat exchanger comprises one or more oil passages extending in the vein of tertiary flow and, fluidically, between the corresponding oil inlet and the corresponding oil outlet.
3 . The axial turbomachine according to claim 1 , wherein each of the angular sectors of the heat exchanger comprises an oil distributor extending circumferentially along the wall and including the oil inlet, and an oil collector extending circumferentially along the internal wall and including the oil outlet.
4 . The axial turbomachine according to claim 3 , wherein each of the angular sectors of the heat exchanger comprises several oil passages extending in the tertiary flow vein and, fluidically, between the oil distributor and the oil collector.
5 . The axial turbomachine according to claim 1 , wherein for each of the angular sectors of the heat exchanger, the oil inlet and/or the oil outlet is integrally formed in the inner wall.
6 . The axial turbomachine according to claim 5 , wherein the short-circuiting passage comprises a normally closed valve capable of opening in a presence of a pressure difference between the oil inlet and the oil outlet, greater than or equal to a limit value.
7 . The axial turbomachine according to claim 5 , wherein the short-circuiting passage is integrally formed in the internal wall.
8 . The axial turbomachine according to claim 1 , wherein for each of the angular sectors of the heat exchanger, the oil inlet and/or the oil outlet are located on a terminal downstream portion of said heat exchanger.
9 . The axial turbomachine according to claim 8 , wherein for each of the angular sectors of the heat exchanger, the oil inlet and/or the oil outlet are located at a distance from a downstream edge of said heat exchanger at the internal wall, which is less than 20% of a total area of said heat exchanger along said internal wall.
10 . The axial turbomachine according to claim 1 , wherein each of the structural arms has, in the tertiary flow vein, a cross section with a width decreasing on a downstream half of said section.
11 . The axial turbomachine according to claim 10 , wherein for each of the angular sectors of the heat exchanger, the oil inlet and the oil outlet are located at a level of the downstream half in axial projections of the cross section of greatest width of the structural arms adjacent to said angular sector.
12 . The axial turbomachine according to claim 3 , wherein the heat exchanger comprises, over a total extent of the heat exchanger along the tertiary flow, a material-free portion forming an air by-pass, said air by-pass being adjacent to the internal wall and adjacent to the oil collector and/or to the oil distributor.
13 . The axial turbomachine according to claim 12 , wherein the air by-pass is delimited radially inwards by the internal wall.
14 . The axial turbomachine according to claim 11 , wherein each of the angular sectors of the heat exchanger comprises an oil inlet passage extending radially and laterally to the air by-pass from the oil inlet and an oil outlet passage extending radially and laterally to the air by-pass towards the oil outlet, said oil inlet and oil outlet passages being located at the downstream half in axial projections of the largest width cross section of the structural arms adjacent to said angular sector.
15 . The axial turbomachine according to claim 12 , wherein the oil inlet passage is spaced from the oil outlet passage by a distance greater than at most 20% more than a circumferential width of the air by-pass.