Patent ID: 8893510

Claim:
A gas turbine engine comprising: a compressor section where air pulled into the engine is compressed; a combustion section where fuel is mixed with at least a portion of the compressed air from the compressor section and burned to create hot combustion gases; a turbine section where the hot combustion gases from the combustion section are expanded to extract energy therefrom, wherein at least a portion of the extracted energy is used to rotate a turbine rotor during a first mode of engine operation comprising full load operation; a rotor chamber in communication with structure to be cooled within the turbine section; at least one rotor cooling pipe that injects primary path air extracted from the engine into the rotor chamber during the first mode of engine operation; and an air injection system comprising: at least one outlet port through which secondary path air is extracted from the engine only during a second mode of engine operation comprising less than full load operation; the at least one rotor cooling pipe, which is used to inject the secondary path air extracted from the at least one outlet port into the rotor chamber during the second mode of engine operation; a piping system that provides fluid communication between the at least one outlet port and the at least one rotor cooling pipe; a blower system for extracting the secondary path air from the engine through the at least one outlet port and for conveying the extracted secondary path air through the piping system and the at least one rotor cooling pipe into the rotor chamber; and a valve system that is opened and closed by a controller based on a temperature differential between a top wall section of an engine casing and a bottom wall section of the engine casing to selectively allow and prevent secondary path air to be extracted from the engine and conveyed through the piping system by the blower system into the rotor chamber.