investigation of the thermo-mechanical and ablative behaviour of silicon carbide based concretes exposed to hybrid propulsion environments.

Paper number

IAC-13,C2,4,6,x17408

Author

Mr. Raffaele D'Elia, Centre National d'Etudes Spatiales (CNES), France

Coauthor

Prof. Thierry Cutard, Mines Albi, France

Coauthor

Prof. Gérard Bernhart, Mines Albi, France

Coauthor

Dr. Marianne Balat Pichelin, Laboratoire Procédés, Matériaux et Energie Solaire, PROMES-CNRS, France

Coauthor

Dr. Gilles Peraudeau, Laboratoire Procédés, Matériaux et Energie Solaire, PROMES-CNRS, France

Year

2013

Abstract

This research is part of the PERSEUS project, a space program concerning hybrid propulsion and supported by CNES. The main goal of this study is to characterize silicon carbide based concretes in a hybrid propulsion environment. The nozzle throat has to resist to a highly oxidizing paraffin/LOX hybrid environment, under temperatures ranging up to 3000°C.
The study is divided in two main parts: the first one deals with the thermo-mechanical characterization of the materials up to 1400°C and the second one with an investigation on the ablation behaviour under a standard or a highly oxidizing atmosphere, up to 3000°C. The combustion time is of 15s. Four concrete grades are considered: the maximum aggregate sizes is of 3mm, 2mm, 1.6mm and of 0.8mm for a micro-concrete.
Young’s modulus was determined by a resonant frequency method and four-point bending creep tests were conducted up to 1200°C. First results show an increase of the Young’s modulus with the stabilisation temperature and a higher value for the concrete with a 3mm aggregate size, compared to the micro-concrete. Creep begins close to the stabilisation temperature. Modelling will be used to choose the better stabilisation temperature and to describe the thermo-mechanical behaviour.
High-temperature ablation tests were made at PROMES-CNRS laboratory, on a 2kW solar furnace, with a concentration factor of 12,000. A 7 to 15 MW/m2 incident solar flux and a 7 to 90 seconds exposure time have been chosen. Optical microscopy, ESEM, EDS and 2D/3D roughness analyses were used to determinate the microstructure evolutions and the degradation kinetics. During tests, silicon carbide undergoes active oxidation, with production of SiO/CO smokes and ablation. A linear relation between mass loss and time is found, accordingly to the Wagner theory (Wagner, 1958), extended to SiC by Hinze and Graham (Hinze & Graham, 1976). Tests at a 15 MW/m2 solar flux value have shown a mass loss of 20 mg/cm2 after 15 seconds for the micro-concrete and for the 3mm aggregate size one. After 90 seconds, mass loss attains 80 mg/cm2 for the micro-concrete and 50 mg/cm2 for 3mm aggregate size concrete.
Micro-concrete is more interesting for the realisation of the nozzle, thanks to its workability. But its thermo-mechanical properties are less favourable than the 3mm aggregate size concrete. After 15 seconds, both concretes undergo the same ablation. Our goal is to improve thermo-mechanical properties and to study micro-concrete under hybrid propulsion environment and to develop a phenomenological model.

Abstract document

IAC-13,C2,4,6,x17408.brief.pdf

Manuscript document

IAC-13,C2,4,6,x17408.pdf (🔒 authorized access only).

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