Ducted fan turbine engine comprising a system involving screens for blocking off the duct for the secondary flow

A ducted fan turbine engine having a longitudinal direction and comprising an engine and a nacelle surrounding the engine which comprises a fan casing wherein a duct for a secondary flow is delimited between the nacelle and the engine and wherein an air flow circulates from a front towards a rear of the ducted fan turbine engine, said nacelle comprising:

• a fixed structure fixed to the fan casing,
• a mobile cowl capable of translational movement on the fixed structure in a direction of translation between a forward position, wherein the mobile cowl is positioned in such a way that it is close up to the fan casing, and a backward position, wherein the mobile cowl is positioned in such a way that it is distant from the fan casing in order to define between the mobile cowl and the fan casing an opening between the duct and the outside of the nacelle,
• a set of actuators causing the mobile cowl to move between the forward position and the backward position, and vice versa,
• a plurality of rollers, each mounted having freedom to rotate on the mobile cowl to a rear of the opening when the mobile cowl is in the backward position,
• for each roller of the plurality of rollers, a flexible screen having a first edge fixed to the roller and a second edge opposite to the first edge, wherein said screen can alternately adopt a furled position wherein said screen is wound up around the roller or a deployed position wherein said screen is unwound from the roller and stretched between the roller and the engine across the duct,
• a deployment mechanism arranged to move the second edge of each of the screens so as to move said screen from the furled position to the deployed position, and
• a furling mechanism arranged to drive each roller of the plurality of rollers in rotation so as to move the screen associated with said roller from the deployed position to the furled position.