Investigation of the combustion characteristics of H$_2$–O$_2$–N$_2$–H$_2$O mixtures under elevated pressures and temperatures

The flammability limits and burning velocity of hydrogen-air mixtures with diluent (nitrogen, steam) have been studied experimentally at temperatures up to 250$^\circ$C and pressures up to 4 MPa. It has been observed that the flammability limits are practically independent of pressure within 2–4 MPa. It is shown that nitrogen and steam as diluents have quantitatively and qualitatively different effects on the burning velocity of stoichiometric hydrogen-air mixtures. The effects observed are interpreted qualitatively.