Ejector Primary Flow Molecular Weight Effects in an Ejector-Ram Rocket Engine

The effects of primary flow molecular weight on the ejector performance in a generic rocket-based combined-cycle engine are examined by using steady-state, one-dimensional compressible flow equations. Ejector performance in terms of specific impulse, bypass ratio, thrust, and thrust augmentation factor are presented for three primary fluids with molecular weights of 2, 18, and 29, covering a range of primary rocket stagnation conditions, ejector geometries, and freestream conditions.