Overview of a Supersonic Probe for Solid Propellant Rocket CCP Collection

Abstract

The present work aims at giving a comprehensive overview of the current development status of an intrusive probe, capable of collecting the condensed combustion products present in the exhaust of a solid rocket motors. The innovative technique was conceived in the EMAP (Experimental Modelling of Alumina Particulate in Solid Booster) framework, a project aiming at characterizing the alumina in terms of size, temperature and spatial distribution to gain detailed information for climatological impact assessment. A supersonic probe was sized to handle a progressive deceleration and cooling of the exhaust gas, as well as the quenching and collection of the suspended particles in a pressure-controlled chamber. The task was achieved by through a quasi 1D gas dynamics code based on the Shapiro method and the normal shock wave theory, which was verified against a hybrid 2D axial-symmetric mesh whose turbulent flow field was solved using the DLR-TAU CFD code. The robustness of the system has been investigated performing a sensitivity and an uncertainty analysis, exploring uncertainties propagation through the numerical code based on Shapiro equations. The sensitivity analysis enabled to define a ranking of importance for the uncertainties on the probe behavior; the uncertainty analysis allowed to estimate failures of the system and/or of the code. Cold flow tests carried out at the vertical facility of DLR-Cologne enabled to gain a proof of concept for both fluid dynamic behavior and collection methodology.