Numerical Simulation of Gas Phase Reaction Chemistry in Methane-Hydrogen Mixtures

In the present work, gas-phase reactions between opposing streams of mixtures of hydrogen (H₂) and methane (CH₄) in the presence of volumetric energy input were simulated. The goal of the simulations is to estimate the concentrations of precursors responsible for the formation of carbon nanotubes (CNTs). These estimates are expected to help in understanding fundamental mechanisms of CNT formation and in controlling the synthesis process through parameters such as inlet composition and temperature, reactor pressure and absorbed energy. The simulation employs gas-phase kinetics of the GRI-2.11 mechanism with only reactions involving molecules that contain C and H atoms. The results indicate that the concentrations of H radicals, C₂H₂ and C atoms increase significantly with increases in volumetric energy deposition rate beyond a threshold.