Turboshaft engine e.g. dual-flow turboshaft engine, has high pressure turbine whose rotor is overlapped on rotor of low pressure turbine so as to form contra-rotating turbine, where turbines are located in primary vein

The engine has a low pressure turbine comprising a rotor (7), and a high pressure turbine comprising another rotor (8). The rotor of the high pressure turbine is overlapped on the rotor of the low pressure turbine so as to form a contra-rotating turbine. A high pressure compressor (5) comprises a rotor (5a) driven in rotation by the rotor of the high pressure turbine. The turbines are located in a primary vein (2) which is separated from a secondary vein (12) by an intermediate casing (13). A combustion chamber (6) is fixed at the intermediate casing. L'invention concerne une turbomachine qui présente un volume réduit tout en présentant un fort taux de dilution. Pour ce faire, la turbomachine comporte: - Une turbine basse pression comportant un rotor (7); - Une turbine haute pression comportant un rotor (8) ; le rotor (8) de la turbine haute pression est imbriqué dans le rotor (7) de la turbine basse pression de façon à former une turbine contrarotative.