Methods and apparatus for supplying cooling air to turbine engines

摘要

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.