A heat exchanger designed to be fixed to a turbomachine wall delimiting a gas flow stream, this exchanger including a body with a front face through which the gas flow passes; an attachment face to the wall; an external face opposite the attachment face and connected to the front face; two lateral faces connected to the front face; a cover surrounding the front face and extending along the prolongation of the external face and the lateral faces, to delimit an intake with an area smaller than the area of the front face, this intake being located upstream from the front face relative to the gas flow stream.

A turbine stator vane or turbine rotor vane has a body, a channel being adapted for leading a cooling fluid through the body, and a flow adaption feature protruding from the body to the channel in such a manner as to reduce a cross-sectional area of the channel.

A noise attenuation panel for a bleed flow is presented that causes a total pressure loss of the bleed flow before it is exhausted. The total pressure loss results from at least two regions in which the flow area contracts and then rapidly expands, with the rapid expansion causing mixing and turbulence rather than full total pressure recovery. This reduced pressure means that when the flow is exhausted into a flow (which may be the bypass flow of a gas turbine engine), its energy, and thus its noise, are reduced.