US Patent 9010121 Combustion chamber

A combustion chamber has an outer wall supporting a number of wall elements or tiles. The tiles are located on the wall by bosses so that a cooling space is provided between the wall and the tiles. Air holes are provided through the wall and the tiles and a flow passage is provided adjacent the air holes. A flow passage is defined by changing the profiles of the air holes in the outer wall and/or the location features to provide a localized gap through which cooling air is directed to cool regions subject to overheating and extend service life.