Abstract: A gas turbine engine diffuser case construction is described that increases the amount of available discharge air for service applications compared to the prior art while reducing downstream component distortion and degradation. The diffuser case has passageways for diffused air that connect a diffused air region to a manifold. At least one orifice is located at the end of each of the passageways in the diffused air region. The size of the orifices controls the amount of air that is discharged from the diffused air region to the manifold. Diffused compressor air collects in the manifold and is then extracted from the manifold as needed for engine or service applications. The size and location of the orifices in the diffuser radially and circumferentially control the rate of discharge of the diffused air from the diffuser before the air enters the combustor region. The ability to influence the flow of air at particular locations around the combustor helps the designer to improve cooling uniformity.

Abstract: This disclosure describes a cooling and manufacturing enhancement for gas turbine engine outer air seals. The invention provides convective cooling in a counter-flow array, internal heat transfer augmentation through the use of boundary layer trip-strips, coolant Mach number control through the use of tapered convective channels, inter-segment purge without additional secondary cooling air, and is castable.