Gas turbine engine thermal management system for heat exchanger using bypass flow

A gas turbine engine comprising:

• a fan nacelle and a core nacelle arranged to provide a bypass flow path;
• a compressor section provide within the core nacelle;
• a heat exchanger arranged within a duct that is configured to receive bypass flow from the bypass flow path, the duct in fluid communication with the compressor section and configured to pass bleed air through the heat exchanger;
• a fan arranged within the duct and configured to selectively increase a pressure differential across the heat exchanger;
• a two way bleed air valve arranged within the duct to selectively communicate fluid from the compressor section and bypass flow to the heat exchanger;
• and
• a controller in communication with the two way bleed air valve, the controller configured to open the two way bleed air valve during undesired bypass flow rates through the heat exchanger, wherein the undesired bypass flow rates are provided at an aircraft park condition and the gas turbine engine is idling.