Quantification of uncertainty on the catalytic property of reusable thermal protection materials from high enthalpy experiments

Abstract

An accurate determination of the catalytic property of thermal protection materials is crucial to design reusable atmospheric entry vehicles. This property is determined by combining experimental measurements and simulations of the reactive boundary layer near the material surface. The inductively-driven Plasmatron facility at the von Karman Institute for Fluid Dynamics provides a test environment to analyze gas-surface interactions under effective hypersonic conditions. In this study, we develop an uncertainty quantification methodology to rebuild values of the gas enthalpy and material catalytic property from Plasmatron experiments. A non-intrusive spectral projection method is coupled with an in-house boundarylayer solver, to propagate uncertainties and provide error bars on the rebuilt gas enthalpy and material catalytic property, as well as to determine which uncertainties have the largest contribution to the outputs of the experiments. We show * Corresponding author. that the uncertainties computed with the methodology developed are significantly reduced compared to those determined using a more conservative engineering approach adopted in the analysis of previous experimental campaigns.

Robust reconstruction of the catalytic properties of thermal protection materials from sparse high-enthalpy facility experimental data

“…Even for well-characterized facilities, the determination of catalytic properties is affected by the noise present in the experimental data. The quantification of uncertainties in high-enthalpy experiments has previously been studied in the literature [13,14,15,16]. In particular, in our previous work [16], we evaluated the uncertainties on catalytic properties by coupling a deterministic catalytic property estimation with a Polynomial Chaos (PC) expansion method.…”

“…The quantification of uncertainties in high-enthalpy experiments has previously been studied in the literature [13,14,15,16]. In particular, in our previous work [16], we evaluated the uncertainties on catalytic properties by coupling a deterministic catalytic property estimation with a Polynomial Chaos (PC) expansion method. The probabilistic treatment of the uncertainties helped mitigating over-conservative uncertainty estimates found in the literature by computing confidence intervals.…”

“…The probabilistic treatment of the uncertainties helped mitigating over-conservative uncertainty estimates found in the literature by computing confidence intervals. The influence of the epistemic uncertainty on the catalytic property of a reference calorimeter used in the reconstruction was also investigated in [16]. However, the method developed has two shortcomings: the number of experiments is limited and statistics about the measurements distribution are not available, even though they are an essential input for the PC approach.…”

Thermal Protection System and Thermal Management for Combined-Cycle Engine: Review and Prospects

“…However, since the combined propulsion system will lead to excessively high local temperature [27] caused by huge heat load and shock wave under extreme thermophysical conditions featuring high speed, high temperature, and high combustion, it is difficult for currently available thermal protection systems to meet the cooling needs of combined propulsion system. For passive thermal protection systems, currently available materials have shortcomings when it comes to high temperature and oxidation resistance [28]. In addition, passive thermal protection systems of combined propulsion also need to bear enough mechanical loads and have excellent performance in ablation resistance, which were rarely explored in past researches [29].…”

Forward and backward uncertainty quantification with active subspaces: Application to hypersonic flows around a cylinder

“…the development of efficient Uncertainty Quantification (UQ) methods. An example of physical system where UQ is highly relevant is high-enthalpy hypersonic fluid dynamics [1,2,3,4,5], a complex problem that involves multidisciplinary aspects, from aero-thermodynamics to gas-surface interaction, and in which some experimental data are difficult to obtain, especially in-flight measurements of entering space vehicles. For example, during the reentry trajectory of a space vehicle, it is extremely challenging to obtain direct measurements of freestream quantities (velocity and thermodynamic state of the atmosphere), due to the presence of a strong bow shock in front of the vehicle nose.…”