2016 Volume 14 Pages 1-7
An air-breathing system using reed valves was developed for Microwave Rocket. No stopper plate was used to avoid interference between the reed valve tip and high-power microwave beams in the thruster tube. Titanium alloy was used for the reed petal because of its high strength. The petal's width and thickness were designed to be tapered to prevent the petal from yielding, and its fundamental frequency, opening area, and the maximum stress on the petal were computed using static analysis. Estimated fundamental frequency agreed well with the measurement, though the opening area and the maximum stress were underestimated because of the inertial force. The experiment was conducted using a high-power microwave generator (gyrotron) to evaluate the air-breathing performance. In the experiment, no plastic deformation was observed on the reed petal and the partial filling rate was deduced as 0.32-0.44 for two reed valve stages (16 reed valves).