Patent ID: 6971852

Claim:
A method of enabling cooling of the engaging fir tree features of a turbine disk and blades during operation of the assembly in a gas turbine engine comprising the steps of truncating the tips of at least one pair of circumferentially spaced projections that with others define said fir tree shapes, in at least one of said disk and on said blades, so as to define cooling air flow paths between the truncated tips of the one and the opposing fir tree roots of the other when said disk and blades are assembled, and connecting said cooling air flow paths to a compressor of said gas turbine engine for the receipt of a supply of cooling air therefrom during operation of said engine, enclosed annular spaces being provided adjacent the upstream and downstream faces of said assembly and connecting said compressor air supply to said truncation defined spaces via said upstream space, for passage therethrough to said downstream space, each blade of the assembly being provided with a cooling air passage through a substantial portion of its length, the cooling air inlet of which passage is in the radially inner end of said blade, and connecting at least said downstream adjacent space in flow series with said cooling air inlet so as to enable a circulatory cooling flow to be established.