Negligibly small effects of radical quenching on flames in MFR with 2 mm diameter at pressures of 1 and 0.5 atm was confirmed by comparing experiments and 2-D computations with reactions of radical quenching at various sticking coefficients [85], which supports an earlier work using optical measurements by a research group of the University of Tokyo [a]. Note that the faint radical quenching effect were seen at 0.1 and 0.05 atm [85] although corresponding sticking coefficient S that reproduces experiments were merely 0.0005. This value is four order smaller than the radical quenching model that published in early 2000 while it is extensively used. In a rigorous consideration, however, the results of [85] indicated that effect of surface reaction could not be ignored in computations at pressure lower than around 0.1 atm in MFR.

We occasionally face a comment like "surface reactions such as radical quenching need to be considered in simulations because of a small channel of MFR." However, its effect is negligibly small in our studies using MFR since typical conditions are 2 mm diameter tube at atmospheric pressure and 1 mm diameter at elevated pressures.