Ion Sensors for Pulsed and Continuous Detonation Combustors

Presented in the article are the design and operation principles of ion sensors intended for detecting the propagating reaction fronts, the deflagration/detonation mode, apparent subsonic/supersonic propagation velocity of the reaction front, and duration of heat release by measuring the ion current in the reactive medium. The electrical circuits for ion sensors without and with intermediate amplifiers, with short response time and high sensitivity, as well as with the very wide dynamic range of operation in the reactive media with highly variable temperature and pressure, are provided and discussed. The main advantages of ion sensors are their very short response time of about 1 ms, versatility of design, and capability of detecting and monitoring reaction fronts of different intensities directly in combustion chambers. Several examples of ion sensor applications in sensing deflagration-to-detonation transition in pulsed detonation engines and developed detonations in rotating detonation engines operating on different fuel–air and fuel–oxygen mixtures are presented and discussed.