Analysis of increased compression through area constriction on ejector-rocket performance

The use of an ejector as part of a larger rocket-based propulsive device is investigated in terms of increasing thrust as compared to a pure rocket system. A theoretical framework is presented to establish the relation between increasing ejector compression and increasing thrust, whereas numerical simulations are presented to demonstrate the viability of using area constriction to achieve increased ejector compression. Using a constant length ejector, the exit area is constricted by between 12 and 25% and compared to a similarly configured unconstricted ejector. In addition, both a purely conical and a conical/cylindrical constriction configuration are examined, in which an increase of 30% in the ejector compression ratio is achieved in the best case.