Properties of turbulent hydrogen-air flames at elevated pressures

Outwardly propagating hydrogen-air turbulent flames were studied at the equivalence ratios from 0.6 to 1.0 and the initial pressures from 0.10 to 0.50 MPa. Turbulence intensity, u′ was set to 0.80 to 1.59 m/s. The Markstein number decreased for increasing pressures and for small equivalence ratios. The ratios of turbulent to unstretched laminar burning velocities at a constant Peclet number increased with increasing turbulence Karlovitz number and decreasing Markstein number at a constant pressure. This burning velocity ratio increased with increasing pressure at the equivalence ratios of 0.6 and 0.8. At the equivalence ratio of 1.0, however, the burning velocity ratio did not increase with increasing pressure although the Markstein number reduced with pressure.