Patent ID: 8181443

Claim:
A gas turbine engine comprising: a gas path having a core flow portion and a bypass flow portion, the core flow portion including at least a compressor, combustor and turbine, the compressor providing compressor air and the bypass flow portion conducting bypass air; a heat exchanger incorporated with at least one portion of turbine case surrounding the turbine, the heat exchanger having first and second air passages, the at least one portion of the turbine case forming a common wall separating and shared by the first and second air passages; and the first air passage in fluid communication with the compressor air for directing a portion of the compressor air through the heat exchanger to cool a turbine system, the second air passage in fluid communication with the bypass air for directing a portion of the bypass air through the heat exchanger to cool the portion of compressor air passing through the heat exchanger, the common wall in the heat exchanger configured to transfer heat from the portion of the compressor air flowing in the first air passage to the portion of the bypass air flowing in the second air passage, to cool the portion of the compressor air, the first air passage being defined between the common wall formed by the at least one portion of the turbine case and an annular inner wall positioned radially, inwardly spaced apart from and supported by the turbine case, the annular inner wall surrounding a turbine shroud casing and including a plurality of holes extending radially through the annular inner wall for directing the cooled portion for the compressor air to impinge on the turbine shroud casing; an apparatus configured for selectively adding an uncooled portion of the compressor air into the cooled portion of the compressor air after being discharged through the holes in the inner wall, in response to a temperature change of the turbine shroud casing of the turbine system, wherein the apparatus comprises an annular inlet introducing the uncooled portion of the compressor air into an annulus defined between the annular inner wall and the turbine shroud casing for receiving the cooled portion of the compressor air discharged from the holes in the inner wall, the inlet being defined between an axial section of the annular inner wall and an axial section of the turbine shroud casing, the inlet thereby changing an opening size when the axial section of the turbine shroud casing changes a size in a radial dimension in response to temperature changes of the turbine shroud casing.