Experimental activities on the paraffin-based fuel MTM in the framework of the PHAEDRA project

Experimental results of the firing test campaign carried out with a 1000 N thrust-class gaseous oxygen/paraffin-based fuel hybrid rocket engine, in the framework of the PHAEDRA project, are presented in this work. The main objective of the test campaign was the characterization and selection of different materials to be used as thermal protection in the full-scale DEMO, under given operative conditions. The test campaign consisted of 16 experimental firing tests, including some preliminary tests conceived to assess the ignition sequence and the thruster operative conditions. Different materials were tested in different regions of the thruster, including rubber-based materials in the pre and post-chamber, and materials able to withstand higher temperatures in the nozzle, such as carbon-phenolic or graphite. The thruster was equipped with different thermo-couples and pressure transducers, allowing the acquisitions of the experimental data needed to assess the thruster behavior and the testing conditions. Several measurements and analyses in the post-test phase allowed the characterization and comparison of the different materials.