Full-shielding double-S-shaped binary injection nozzle of variable cycle engine

The invention discloses a full-shielding double-S-shaped binary injection nozzle of a variable cycle engine, and belongs to the technical field of aero-engines. The dual-S-shaped injection nozzle comprises a dual-S-shaped convergence section and a dual-S injection nozzle body arranged at an outlet of the dual-S-shaped convergence section. The outlet offset distance of the binary injection nozzle is 0; the double-S-shaped convergent section comprises an inner outer duct S-shaped convergent section and a peripheral third duct S-shaped convergent section, the cross sections of the outer duct S-shaped convergent section and the third duct S-shaped convergent section are both hyperelliptical, and the outer duct S-shaped convergent section and the third duct S-shaped convergent section have the same S-bend center line and are not communicated with each other; the main flow with the high total pressure and temperature at the outlet of the S-shaped convergence section of the outer duct passes through the secondary fl