Reduced-order Models for Radiative Heat Loads Estimation in Liquid Rocket Engines

Accurate prediction of radiative heat transfer is crucial for the thermal design of liquid rocket engines, where ra- diation can contribute up to 30% of the wall heat load. High-fidelity models, though accurate, are computationally prohibitive for design applications. This work presents a reduced-order model coupling chemical equilibrium calcu- lations, state-of-the-art radiative properties, and semi-analytical heat flux expressions in axisymmetric chambers. The model is validated against CFD-based discrete transfer method results for oxygen–methane engines, showing excellent agreement. It also accounts for wall emissivity, injection effects, and different propellant combinations, providing an efficient and reliable tool for preliminary design studies.