Ablative material behavior in oxygen/methane thruster environment

Ablative materials represent a low cost and reliable means to insulate rocket engine components from high-temperature, corrosive combustion product environments. Besides their diffuse application in solid rocket nozzles, their use also emerges as a valid alternative in liquid rocket engines. Together with the growing interest in oxygen/methane liquid rocket engines, these materials have gained attention as possible insulator for small upperstage engines or in-space thrusters. In this framework, a validated approach for the study of carbon-based pyrolyzing and non-pyrolyzing materials, together with a novel boundary condition developed to analyze the silica-based material behavior, has been used to numerically reproduce the material response in the highly oxidizing environment generated by the combustion of oxygen and methane. At first, the validation against experimental data of the silica-based material erosion model is presented. Subsequently, the behavior and the response of different ablators in a oxygen/methane environment is numerically investigated for a wide range of operating conditions. Commonly made assumptions in the simulation of the material response are thoroughly analyzed and a critical overview of the results is presented. © 2012 by Alessandro Turchi, Daniele Bianchi, Francesco Nasuti, Renato Marocco.