Methods and apparatus for supplying cooling air to turbine engines

摘要

A cooling air cooling system (40) is selectively operable to reduce fuel gum deposits within the cooling system during gas turbine engine operations. The cooling system includes a recirculating loop (46) that includes at least three heat exchangers (50, 52, 54) in fluid communication with the recirculating loop. A first heat exchanger cools cooling air (42) supplied to the gas turbine engine. A second heat exchanger cools fluid exiting the first of the heat exchangers with fan discharge air (43) prior to the fluid entering the third heat exchanger. A third heat exchanger uses combustor main fuel flow (44) to cool the fluid circulating in the recirculating loop. <IMAGE>