In a bootstrap system, what happens to bleed air downstream of the first heat exchanger?

In a bootstrap system, the process involving bleed air downstream of the first heat exchanger is crucial for understanding how heat is managed and energy is transferred within the system. In this context, selecting the correct sequence of actions highlights the system's efficiency and functionality.

The bleed air, after it is cooled in the first heat exchanger, is compressed. This initial compression is essential because it facilitates the subsequent steps where the air's properties must be adjusted further for use in the system. Following this compression, the air is directed through a secondary heat exchanger. This secondary heat exchanger serves to optimize the thermal management of the air before it reaches the next stage, which is the expansion turbine.

By passing first through compression and then through a secondary heat exchanger, the air can be conditioned to a suitable temperature and pressure that ensures efficient performance in the expansion turbine. The expansion turbine then takes this conditioned air and allows it to expand, performing work on the surrounding system and ultimately contributing to the propulsion or other functional needs of the aircraft.

The correct process ensures that the system operates optimally, making this choice a critical aspect of understanding the functioning of a bootstrap system.