Experimental Study of a Resonance Igniter for Rocket Engines

Currently, most used storable liquid propellant combination for space propulsion consists of hydrazine derivates and nitrous tetroxide which can be easily ignited due to their hypergolic properties. On the contrary there are some problems related to its polluting and toxic effects, which are no longer tolerated in today's society. These aspects have led the researchers to focus on greener propellants which, unfortunately, are not able to form hypergolic combinations thus requiring an igniter. A possible solution is a resonant igniter. This device uses the pressure level of the propellant itself to heat a small portion of gas by means of resonance effects, thus determining ignition. It has many advantages like the lack of both moving parts and electrical circuits. The aim of this thesis is to carry out an experimental and comprehensive investigation of the ignition method. After a first part of the work dedicated to the analysis of the historical development and the state of the art, the experimental section follows. This experimental part contains the description of the tests performed, the modifications applied to the experimental apparatus and the different geometries of the resonator. The latter is the main component of the ignition system, whose shape greatly influences the outcome of the experiments. In the final part, we collected the results emerged during the study including the indication of the maximum temperatures reached in the tests that in some configuration exceeded 1000 K. The results obtained are in line with the findings of other research groups and represent a solid background for further studies.