Comprehensive Investigation of Hydrogen Autoignition Kinetics Under Elevated Pressures

The study presents a comprehensive experimental and numerical investigation of the autoignition kinetics of a hydrogen–air mixture under elevated pressures relevant to modern energy systems. Experiments were conducted using high-pressure constant-volume and constant-pressure reactors as well as a flow reactor to evaluate induction periods across a wide range of temperatures, pressures, and gas compositions. The results demonstrated that increasing pressure from 2.9 to 8 MPa reduced the induction period by more than half, with measured times varying from 1.21 seconds at 550 K and 3 MPa to 0.21 seconds at 750 K and 6 MPa. The addition of inert gases, dilution, and heat-absorption effects. A new global kinetic equation was derived, characterized by an activation energy of approximately 170,000 J/mol and reaction orders of 1.1 for oxygen and 0.3 for hydrogen. Validation against detailed kinetic mechanisms and literature data confirmed deviations within 10–12%, demonstrating high predictive accuracy. The proposed equation for modelling hydrogen oxidation in engineering applications operating at high pressures.