Propulsion Systems with Air Precooling for Aerospaceplane

Using LH2 heat sink capacity for air precooling in turbojets allows to increase specific impulse and in many cases to reduce specific mass (mass-to-sea level thrust ratio).

A number of precooled turbojet schemes are considered. Classification of turbojet according to the cooled air amount and depth of cooling is proposed. ATR with extended precooling (Tout=100K) is examined in more detail.

For propulsion systems including different types of engines, running simultaneously the concept of LH2 heat sink capacity concentration for turbojet air precooling is proposed.