High-pressure hydrogen/carbon monoxide syngas turbulent burning velocities measured at constant turbulent Reynolds numbers

Using a double-chamber explosion facility, we measure high-pressure turbulent burning velocities (S _T) of lean syngas (35%H ₂/65%CO) spherical flames at constant turbulent Reynolds numbers (Re _T ≡ u′L _I/ν) varying from 6700 to 14,200, where the root-mean-square turbulent fluctuation velocity (u′) and the integral length scale (L _I) are adjusted in proportion to the decreasing kinematic viscosity of reactants (ν) at elevated pressure (p) up to 1.2 MPa. Results show that, contrary to popular scenario for turbulent flames, at constant Re _T, S _T decreases similarly as laminar burning velocities (S _L) with increasing p in minus exponential manners. Moreover, at constant p, S _T/S _L increases noticeably with increasing Re _T. It is found that the present very scattering S _T/S _L data at different p and Re _T can be nicely merged onto a relation of S _T/u′ = 0.49Da ^0.25, where Da is the turbulent Damköhler number and values of S _T/u′ tends to level-off when Da > 160 and p > 0.7 MPa.