AbstractThis paper reports a set of modeling studies that were undertaken to acquire a more detailed knowledge of combustion inhibition mechanisms. Mixtures of H2/O2/Ar reacting in the idealized perfectly stirred reactor were investigated. Three H2/O2kinetic mechanisms were considered, differing from one another by the number of HO2reactions included. Two physical inhibitors, Ar and N2, and one chemical inhibitor, HBr, were investigated. Additional parameters considered were pressure, equivalence ratio, inhibitor concentration and rate coefficient variation. The most effective inhibitor was HBr which acted chemically and caused substantial reduction in radical concentrations in the mixtures considered. The molecules Ar and N2acted as physical diluents with N2, the more effective of the two due to its larger heat capacity.