Air-Breathing System Using Reed Valve for Pulse Detonation Microwave Rocket

Abstract

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).

Discharge from a high-intensity millimeter wave beam and its application to propulsion

“…In 2013, Fukunari et al proposed a reed valve system to improve the thrust performance under repetitive pulse operation by increasing the partial filling rate of the rocket nozzle [94]. A launch experiment using the reed valves was conducted by irradiating 170 GHz, 1.16-MW microwaves to the rocket nozzle [95,96]. The 16 reed valves were installed on the thruster wall to improve the refilling performance.…”

Development of a Novel Launch System Microwave Rocket Powered by Millimeter-Wave Discharge

“…Reed valves open passively by the pressure difference between those inside and outside of the tube. A tapered-shape reed valve, which is capable of opening widely toward the inside without a stopper, was designed and tested [24]. A stopper designed to prevent plastic deformation of the valve was not used because it interacts with intense electromagnetic waves inside the tube.…”