Effect of burner diameter on the burning velocity of premixed turbulent flames stabilized on Bunsen-type burners

• Effect of burner diameter on the turbulent burning velocity was investigated experimentally.
• Particle image velocimetry and Rayleigh scattering techniques were used for measurements.
• Flame height decreased with increasing equivalence ratio from 0.6 to 1.0.
• Turbulent burning velocity was found to be higher for the larger burner.

Influence of burner diameter on the turbulent burning velocity of premixed turbulent methane/air flames was studied on two Bunsen-type burners with nozzle inner diameters of 11.1 and 22.2 mm. The equivalence ratio was varied from 0.6 to 1.0. The non-dimensional turbulence intensity, non-dimensional bulk flow velocity, and non-dimensional longitudinal integral length scale were kept constant for a given equivalence ratio for both burners. Particle image velocimetry and Rayleigh scattering techniques were used to measure the instantaneous velocity and temperature fields, respectively. The characteristic flame height decreased with increasing equivalence ratio from 0.6 to 1.0 for both burners, whereas it increased considerably by increasing the burner diameter. The transverse profiles of the leading edge and half-burning surface flame surface densities showed a tall and narrow region at each side of the burner exit, whereas they were distributed over a larger area farther downstream of the burner exit. The leading edge and half-burning surface wrinkling factors were found to be higher for the larger burner farther downstream of the burner, whereas they are about the same near the burner exit. The non-dimensional leading edge turbulent burning velocity increased with increasing non-dimensional turbulence intensity for both burners. However, the leading edge turbulent burning velocity was found to be higher with the larger size burner.