Effects of hydrogen addition and nitrogen dilution on the laminar flame characteristics of premixed methane–air flames

Effects of electric field intensity and distribution on flame propagation speed of CH4/O2/N2 flames

“…When |d| < 6 mm, the flame ignition energy has a significant impact on the development of the flame [28]; when |d| > 25 mm, both of the pressure change and the temperature change in the bomb are so large that their impact on the flame development cannot be ignored, and the high-voltage electrodes structure and the bomb wall also show a great effect [29,30]. Thus, the computation area is selected as |d| = 6-25 mm where the impact of the horizontal electric field on the flame propagation is analyzed.…”

Time-Resolved Particle Image Velocimetry of dynamic interactions between hydrogen-enriched methane/air premixed flames and toroidal vortex structures

“…Experimental and computational studies performed in simplified flow configurations (freely and spherically propagating flames, counterflow flames, Bunsen-type and slot burners) have shown that the hydrogen addition to methane increases the laminar burning velocity (i.e., the flame reactivity) [5][6][7][8][9][10], the resistance to strain extinction [1,[5][6][7]9,11] and the flame front wrinkling (i.e., the flame surface area) [4,7], thus enhancing robustness and stability of the flame. These positive effects have been attributed to the increase in both flame temperature (thermal effects) and supply of active radicals (chemical effects).…”

Combining experimental and numerical investigations to explore the potential of downsized engines operating with methane/hydrogen blends

“…Nevertheless, one of the limits of this correlation is that it does not take into account the pressure effects and that it is only adapted to hydrogen volume ratios below 40%. The pressure effects on the mixtures were experimentally studied by Tahtouh [59], but only for i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 7 ( 2 0 1 2 ) 1 1 5 1 4 e1 1 5 3 0 values below 10 bar and hydrogen ratios below 40%. These investigation limits are mostly due to experimental risks and to the occurrence of hydrodynamic and thermo-diffusive instabilities, which prevent the determination of laminar flame speeds in engine conditions.…”