At the time of the first firing of the POD-Y demonstrator for the future Ariane 6 and Vega C launchers, ONERA was able to gather unsteady pressure data with a precision of a few mbar.
© DGA-EM. Firing of the POD-Y demonstrator on the 4th of March, 2015
This POD-Y demonstrator, designed to study pressure oscillations inside the P120C solid rocket motor of the future Ariane 6 was fired at the DGA-EM site of Saint-Jean-d'Illac (Gironde). Uncontrolled, these combustion instabilities could indeed disrupt the comfort of payloads carried by the launcher.
This project is a CNES-ESA cooperation. ONERA is partnering in it with Safran Herakles, the developer of the engine, to design, implement and validate the entire measuring system, from the integration of the sensors into the demonstrator to the recording of unsteady data.
The firing, which in particular enabled the performance of a new rocket fuel formula designed to significantly reduce the oscillations to be tested, went perfectly. The precision of the unsteady data* gathered by ONERA is of a few mbar, compared to a maximum pressure of about a hundred bars. ONERA is one of the few laboratories in the world to achieve this kind of measurement under these conditions.
This test will make it possible to address a veritable challenge, thanks to the 6 ONERA sensors placed inside the demonstrator. The engineers have collected a large amount of data, sufficient to validate the numerical models (used as design tools) and to check the expected performance. The processing of these data will soon be performed at ONERA.
*unsteady: unstable over time
