Detached eddy simulation of the heat release characteristics of H₂-O₂ reacting flow in supercritical water

The mild H₂-O₂ reaction is critical for coal-gasification-based polygeneration of power and heat in supercritical water. Time-averaged methods turbulence studies cannot accurately predict the flow, reaction, and heat release during the start-up of the H₂-O₂ reaction, which was crucial for the start-up and safe operation of supercritical water environment oxidation reactors (SCOR). In contrast, ordinary time-accurate method studies require a tremendous computational effort. Detached eddy simulation (DES), a hybrid model, could balance numerical simulation's computational accuracy and speed. Consequently, this paper has conducted a DES investigation on the start-up process of H₂-O₂ reaction in SCW with detailed kinetics. Through this article, the spatio-temporal distribution and reaction structure of the H₂-O₂ reaction start-up process had been unveiled. The process could be divided into the transition and the steady stage, with H₂ mass fraction (X_H2) and inlet temperature significantly affecting the H₂-O₂ reaction start-up process. Moreover, the stability of the H₂-O₂ reaction start-up process was heavily influenced by the X_H2. This numerical study could guide the design, scale-up and optimization of SCOR.