Recognition of MILD combustion regimes of hydrogen oxy-combustion diluted with steam

Abstract

The aim of this study is to explore and define the boundaries of MILD (Moderate or Intense Low-oxygen Dilution) combustion regimes in hydrogen–oxygen–steam systems, advancing the understanding of this efficient, low-emission combustion process. To achieve this, three methodologies were employed: a simplified energy balance, equilibrium modeling, and the Perfectly Stirred Reactor (PSR) model, with the latter providing detailed insights into ignition and extinction behaviors. Validation of the computational approach was conducted through code-to-code comparisons between Cantera and Chemkin environments, ensuring the reliability of results and showing the discrepancies between steady state and transient based calculations. Additionally, various reaction mechanisms were analyzed, highlighting the importance of detailed mechanisms over simplified one-step models for accurate predictions. Combustion maps were created to delineate regime transitions under varying parameters, including pressure, equivalence ratio, and heat loss. These maps provide practical guidance for optimizing MILD combustion systems in applications such as gas turbines and steam generators, supporting the development of sustainable energy technologies.