The present work deals with numerical and experimental investigation of supersonic air-air
ejectors. The numerical investigation is based on flow equations governing turbulent,
compressible, two-dimensional, steady, time averaged and boundary layer equations. These
equations are continuity, momentum and energy. In addition, turbulent shear stress and heat
transfer are calculated using eddy viscosity model. These equations are solved iteratively using
finite difference method under the conditions of different flow regimes which can be divided into
several distinctive regions where, the methods for estimating the mixing length are different for
each flow region. The first region depicts the wall boundary layer, jet shear layer and secondary
and primary potential flow. Tlle second one contains a single region of developing flow. The
present results are concerned with the static pressure coefficient, temperature and velocity
distributions along the mixing duct and diffuser. Also the overall efficiency of the ejectors for
different flow conditions such as, motive air stagnation pressure and temperature, secondary air
temperature and mass ratio is calculated. A simple ejector with convergent-divergent primary
nozzle was fabricated and experimentally tested. The present theoretical and experimental results
are compared with published data. This comparison shows a good agreement. The results obtained
help to understand the flow behavior and physical phenomena occurring in the flow through
ejectors.