Uncertainty quantification of reacting fluids interacting with porous media using a hybrid physics-based and data-driven approach

Accurately simulating coupled physical processes under uncertainty is essential for reliable modeling and design in performance-critical applications such as combustion systems. Ablative heat shield design, as a specific example of this class, involves modeling multi-physics interactions between reacting flows and a porous material. Repeatedly evaluating these models to quantify parametric uncertainties would be prohibitively computationally expensive. In this work, we combine physics-based modeling using a single-domain approach with data-driven reduced-order modeling to quantify uncertainty via the operator inference method. The detailed physics-based simulations reproduce the measured surface temperature of an object exposed to high-enthalpy flow in a plasma wind tunnel experiment within 5 %. We further use the model to demonstrate the effect of complex flow situations on the dynamic interactions between the porous heat shield material and the surrounding gas. The parametric reduced-order model, built on physics-based simulation data, successfully captures variations in quantities of interest resulting from changes in the permeability and heat transfer coefficient of the porous material in two separate studies: solid fuel combustion and emission of buoyant reacting plumes in quiescent air and ablation in a wind tunnel.