Numerical investigation of partially premixed fuel-rich hydrogen-air combustion at sub-atmospheric pressures

"The global energy crisis necessitates the development of sustainable energy sources, with nuclear fusion representing a significant long-term opportunity for the future. However, the licensing process for facilities like ITER involves complex safety-related challenges, such as the investigation of standardized accident reference scenarios involving hydrogen. Following experimental studies at ITER on early controlled combustion as a potential mitigation technique, this work investigates such scenarios using computational fluid dynamics. The study primarily utilizes a combustion model based on the reaction progress variable. Given that here the laminar burning velocity S0L of hydrogen is a decisive factor, a customized correlation was developed to describe S0L as a function of equivalence ratio, temperature, and pressure, based on a literature review of measurements covering a wide range of these conditions. Numerical validation was subsequently attempted against experimental results of the spherical bomb approach for evaluating S0L, where different sub-models and numerical parameters were varied. Finally, a large-scale simulation of ITER test scenarios was conducted to evaluate to what extent the applied models are capable of reproducing these safety-relevant scenarios".