Kyle Gaiser with Daniel Paxson (NASA) and James T’ien

Improved Design of a Self-Actuated Valve for Pulsejet Combustors

Pressure gain combustion is a developing area of research that attempts to achieve more efficient aircraft engines, which typically suffer pressure loss across the combustor. If instead, the pressure can be increased, more work is extracted and more thrust is generated. One way to attain pressure gain is by using resonant pulsed combustion. The NASA Glenn Research Center experiment uses a commercially available pulsejet for this purpose. The pulsejet allows for high frequency pulsed combustion (220Hz) instead of continuous combustion, which aircraft currently employ. The pulsejet is a relatively simple design with only one moving part: a reed valve that opens and closes with each combustion cycle. The valve is also self-actuating, meaning its operation is driven by the physical processes that occur in the chamber during combustion. However, the valve has a notoriously short lifetime and its design is outdated. Given the tremendous stresses from high frequency blasts, as well as the high temperature and pressure conditions, the reed valves at Glenn have lasted a maximum of 20 seconds. The conditions inside the pulsejet and the current valve will be modeled and an improved valve will be designed. If the design proves successful compared to model, it will be fabricated and tested at the Glenn facility. With new materials, technology, and testing, there is good potential for an improved reed valve design and thus, a significant advancement in pulsejet combustors.