Confluence structure of a primary stream and a secondary stream in a bypass turbine engine

A confluence structure of a primary stream and a secondary stream, surrounding the primary stream, of an aircraft engine, the confluence structure comprising:

• a confluence plate separating the primary stream and the secondary stream downstream of a low pressure turbine and having a revolution shape and a downstream end, according to a direction of flow of gas in the primary stream and the secondary stream in an axial direction of the engine, the primary stream containing blades of compressors and turbines, and a combustion chamber, the secondary stream being limited externally, in a radial direction of the engine, by an outer casing,
• wherein the confluence plate has a moving part, adjustably sliding in the axial direction with respect to a complementary part, fixed with respect to the outer casing, of said confluence plate, the moving part comprising the downstream end, the primary stream and the secondary stream joining together only downstream of said downstream end, and
• wherein a shell is mounted in the outer casing while delimiting an annular outer channel therewith, the shell extending notably downstream of the downstream end of the confluence plate and having an upstream end, according to said direction of flow of gases, wherein the shell has a moving part, comprising the upstream end and adjustably sliding in the axial direction with respect to a complementary part, fixed with respect to the outer casing, of said shell.