Experimental Investigations of Mini-Pulsejet Engines

Abstract

An experimental 8 cm pulsejet was developed using scaling laws from research on both 50 and 15 cm pulsejets. The 8 cm jet operates in three different inlet configurations—conventional, perpendicular, and rearward. The rearward configuration features inlets facing in the opposite direction of the flight path and develops the maximum net thrust. Using a high frequency pressure transducer, the operational frequency of the pulsejet was obtained by monitoring the combustion chamber pressure. It was found that in the rearward configuration, the operational frequency of the jet decreases with increasing inlet length. In addition, the combustion chamber peak pressure rise per cycle increases significantly if the exhaust diameter is reduced. Using information from the 8 cm pulsejet, a 4.5 cm pulsejet was developed and is operational.