Turbine engine assembly and method of operating such

A cooling system for a turbine engine assembly, said cooling system comprising:

• a cooling system turbine configured to receive a first airflow at a first pressure and a first temperature and discharge a second airflow at a second pressure less than the first pressure;
• a heat exchanger configured to receive the second airflow and discharge a third airflow at a second temperature less than the first temperature;
• a cooling system compressor rotatably coupled to said cooling system turbine, said cooling system compressor configured to receive the third airflow and discharge a fourth airflow at a third pressure greater than the first pressure;
• and
• a conduit coupled in flow communication with said cooling system compressor and configured to direct the fourth airflow towards the turbine engine assembly for cooling the turbine engine assembly.

A method of cooling a turbine engine assembly, said method comprising:

• rotating a core turbine to induce rotation of a core compressor coupled to the core turbine;
• discharging a first airflow from the core compressor at a first temperature and a first pressure;
• directing the first airflow toward a cooling system turbine;
• discharging from the cooling system turbine a second airflow at a second pressure less than the first pressure;
• directing the second airflow towards a heat exchanger;
• discharging from the heat exchanger a third airflow at a second temperature less than the first temperature;
• directing the third airflow toward a cooling system compressor rotatably coupled to the cooling system turbine;
• and
• discharging from the cooling system compressor a fourth airflow at a third pressure greater than the first pressure.