EJECTOR PUMPING ENHANCEMENT THROUGH PULSING PRIMARY FLOW

摘要

Computational Fluid Dynamics analysis for a novel pulsed-ejector showed that the pumping effectiveness (ratio of secondary (entrainment) to primary mass flow rate) was significantly increased relative to the unpulsed ejector, and that this was optimized by pulsing at off-resonance (3250 Hz) to the fundamental (2000 Hz) of the ejector. Testing of a novel model pulsed-ejector confirmed strong response for pulse frequencies less than half of the fundamental frequency of about 746 Hz. Acoustic driver frequency response limitations only allowed testing at less than the experimental fundamental frequency. Specifically pumping effectiveness was increased by up to five times, and even more in suction performance, for only 150 W electrical power at the acoustic driver input. Optimum performance was at a frequency of about 250 Hz, and the acoustic drive produced a small but significant increase in the flow stagnation pressure. The results demonstrate important research potential for the novel pulsed-ejector.