Abstract: A cooling air cooling system is selectively operable to reduce fuel gum deposits within the cooling system during gas turbine engine operations. The cooling system includes a recirculating loop that includes at least three heat exchangers in fluid communication with the recirculating loop. A first heat exchanger cools cooling air supplied to the gas turbine engine. A second heat exchanger cools fluid exiting the first of the heat exchangers with fan discharge air prior to the fluid entering the third heat exchanger. A third heat exchanger uses combustor main fuel flow to cool the fluid circulating in the recirculating loop.

Abstract: An apparatus and method including a closed-circuit coolable airfoil assembly for use and exposure in a hot fluid flow of a machine portion. The assembly includes a first flange configured to be connected with a casing of the machine portion. A second flange is configured to be connected with the casing. An airfoil is connected with and between the first flange and the second flange, the airfoil including a peripheral portion surrounding a medial portion. At least one channel is disposed in the peripheral portion, the channel extending between the first flange and the second flange and being in flow communication with each. A closed flow path is formed from the casing and through the first flange, the second flange and the channel in which a coolant fluid can pass to cool the airfoil assembly.