Laminar burning velocities of hydrogen-oxygen-steam mixtures at elevated temperatures and pressures

Effects of elevated temperatures (up to 573 K) and pressures (up to 72 bar) on the laminar flame velocity of hydrogen-oxygen-steam mixtures were studied both experimentally and computationally. Stoichiometric hydrogen-oxygen mixtures diluted with steam up to 85% (mol.) have been tested in a spherical explosion chamber with an inner diameter of 25 cm using the pressure method and high speed shadow cinematography. The experimental data on the laminar burning velocity were compared with numerical calculations that used different H/O reaction mechanisms based on the Lutz, GRI-Mech 3.0, Li and Warnatz schemes. The calculations were performed with three codes: INSFLA, Cantera (for unstretched planar flames) and our own FP-code (based on the PREMIX code). Nonmonotonic pressure dependence and strong suppressing effect of steam dilution on laminar flame velocity was found both experimentally and numerically. The best consistency with the experimental measurements of the laminar flame velocity at elevated pressures and temperatures in presence of high steam concentrations was found for the Lutz H/O mechanism.