An experimental investigation of the internal flow in an ejector with flap-excited primary jet

The internal flow in a two-dimensional ejector was investigated with the main jet subjected to excitation by an oscillating flap located just downstream of the jet exit. Mean velocity profiles measured in the constant area mixing duct indicated appreciable increase in mixing due to excitation. However, excitation had only a minor effect on induced mass flow. The performance of the ejector was examined with a two-dimensional diffuser attached to the constant area mixing duct in two different modes, namely divergence perpendicular and parallel to the nozzle of the jet. The rate of induced mass flow was maximum at 8 deg for vertical diffuser and at 12 deg for horizontal diffuser. By segmenting the primary jet into a multi-jet configuration it was possible to increase the entrainment ratio by 40 percent.