Patent ID: 8668440

Claim:
A platform segment for supporting a nozzle guide vane for a gas turbine, the platform segment comprising: a gas passage surface arranged to be in contact with a streaming gas exhausted from a combustor, wherein the streaming gas streams along the gas passage surface in a streaming direction; a cooling surface opposite to and thermally connected to the gas passage surface and arranged to be in contact with a cooling fluid; a wall protruding from the cooling surface and extending at least partially in the streaming direction, wherein the wall is arranged circumferentially between positions, at which adjacent guide vanes are to be provided, such that cooling fluid is channeled by the wall for cooling a downstream portion of the cooling surfaces; and a further wall protruding from the cooling surface an extending at least partially in the streaming direction, wherein a circumferential distance between the wall and the further wall decreases along the streaming direction, wherein the nozzle guide vane having a pressure surface and a suction surface is connectable at the platform segment such that the pressure surface and the platform segment form a first edge along a first curved line where the pressure surface and the platform segment join, the first curved line resembling a part of an airfoil profile of the guide vane and such that the suction surface and the platform segment form a second edge along a second curved line where the suction surface and the platform segment join the second line resembling another part of the airfoil profile of the guide vane, wherein the wall and the further wall extend approximately parallel to the first edge and the second edge, wherein a width of a channel limited by the wall and the further wall decreases from an upstream portion of the cooling surface to the downstream portion of the cooling surface, wherein the upstream portion of the cooling surface has a similar axial position as an similar axial position as a downstream edge of the nozzle guide vane, wherein the wall comprises a first section protruding from the cooling surface to a maximal extent and a second section protruding from the cooling surface between 0.2 times and 0.8 times the maximal extent.