Wall cooling device

A wall-cooling device for cooling a wall (10) having a first face subjected to a heat source and a second face along which an outer fluid flows at a temperature that is lower than T in order to maintain said wall at a temperature that is substantially equal to the temperature T, the device being characterized in that it comprises at least one cooling part (12) including a fastening portion (14) and a cooling portion (16), said part being made of a thermally-conductive shape-memory alloy having a transition temperature T, said fastener portion including fastener means for fastening it rigidly on the second face (10b) of said wall, said cooling portion being shaped so that it takes up a first position that is substantially parallel to said wall when the temperature of the wall is lower than said temperature T and, if the temperature of the wall is at least equal to T, so that it takes up a second position in which the mean plane of said second portion defines, relative to a plane tangential to said wall, a dihedral angle lying in the range 45° to 90°.