Use of streamwise vorticity to increase mass entrainment in a cylindrical ejector

The following work documents the effect of streamwise vortices generated at the nozzle exit of an axisymmetric air jet on the amount of mass entrained into an ejector. In an experimental analysis of the mass entrainment of circular jet ejectors, we found that the introduction of half-delta-wing vortex generators in the exit of the jet nozzle (Reynolds number of 50,000) increased the amount of entrained mass by as much as 40% over the amount of increase provided by the ejector alone. The effectiveness of the generators was studied for several cases varying ejector diameter, length, spacing, and Reynolds number. Although the performance of an ejector is a strong function of these parameters, the mass entrainment increased in all cases studied due to the presence of the vortex generators.