System for controlling speed transition and thrust vectorisation in a multiple-shaped nozzle by secondary injection

A divergent section comprising multiple curved contours for propulsion nozzle of an engine for aircraft or spacecraft propelled by chemical reaction, said nozzle being a nozzle having rotational symmetry about an axis, said engine comprising a reaction chamber producing propulsion gases intended to be ejected outside the nozzle essentially in a main stream, said divergent section comprising from the nozzle throat:

• a first portion comprising a first wall having a first surface of revolution about the axis of the nozzle, so that said first wall has a first curved profile in an axial plane, said first curved profile being suitable for generating a flow of said propulsion gases adapted to operation at low altitudes;
• a second portion having a total length L, which is connected to said first portion at a connecting zone defining a curved contour discontinuity, said second portion comprising a second wall having a second surface of revolution about the axis of the nozzle, so that said second wall has a second curved profile in an axial plane, said second curved profile being suitable for generating a flow of said propulsion gases adapted to operation at high altitudes, and
• a device for controlled injection of at least one additional jet of gas into the main stream of propulsion gases exhausted by the nozzle;
• said divergent section further comprising that said controlled injection device is connected to one or more orifices or group of orifices produced axisymmetrically in said second wall of said divergent section, so that the injection of the additional jet of gas is carried out radially or inclined counterflow to the main stream, said orifice or orifices being arranged therein at a distance d from said connecting zone comprising a curved contour discontinuity which is equal to or less than 95% of the total length L of said second portion and greater than 1% of the total length L of said second portion.