Turbofan engine comprising an outlet cone cooled by its secondary flow

A turbofan engine including

• an exhaust casing through which passes a primary flow and which is surrounded by a secondary flow, both the primary flow and the secondary flow circulating from upstream to downstream along a central longitudinal axis of the turbofan engine during operation, and
• an outlet cone having an upstream end carried by this exhaust casing, the outlet cone delimiting an inner space,
• wherein the exhaust casing includes a hollow radial arm crossing the primary flow which conveys part of the secondary flow in order to form a cooling flow to cool down one or several component(s) located in the inner space,
• wherein the outlet cone terminates in an outlet for discharging the cooling flow,
• wherein the outlet cone is formed by a main wall and includes an inner lining wall which runs along the main wall while being spaced therefrom so as to delimit, together with this main wall along most of an inner face of the main wall, an inter-wall space, and
• wherein a portion of the cooling flow passes through the inter-wall space before being discharged by the outlet, and
• wherein the inner lining wall comprises an extension into the hollow radial arm to collect the portion of the cooling flow that passes through the inter-wall space.