High efficiency thermal engine

Thermal engine comprising:

• two independent rotors (3,4,4′), each respectively mounted in one of two casings (5,6,6′), the first rotor (3) belonging to a low pressure stage (1), the second rotor (4,4′) belonging to a high pressure stage (2,2′), each stage (1,2,2′) provided with its rotor (3,4,4′) and associated fixed fluid preparation members (9,10,13,14,89,91,92,93) combining gas compression means, known as compressors (15,16,90), and gas expansion means, known as expanders (17,18,90);
• and
• at least one combustion chamber (19,20) situated within a substantially cylindrical central volume defined
• at its bases by the two rotors (3, 4, 4′) and their casings (5, 6, 6′), and
• at its lateral surface by a first substantially cylindrical wall (22), in an inner radial positions;
• said first wall being substantially coaxial with a second substantially cylindrical wall (23) in an intermediate radial position, these defining between them a first duct (26) connecting the outlet of the compressor (16,90) of the high pressure stage to the inlet of a first combustion chamber (19);
• and said second wall (23) being substantially coaxial with a third substantially cylindrical wall (24) in an outer radial position, these defining between them a second duct (25), outside the first duct (26) and connecting the outlet of the compressor (15) of the low pressure stage (1) to the inlet of the compressor (16, 90) of the high pressure stage (2, 2′);
• the outlet of the first combustion chamber (19) supplying the expander (18,90) of the high pressure stage (2,2′) with gases produced by combustion, guided from the outlet of the expander (18,90) of the high pressure stage (2,2′) to the inlet of the expander (17) of the low pressure stage (1), the outlet of which is in communication with the outside of a casing (24,27,31) of the engine via at least one exhaust opening (41) for the gases produced by combustion.