Nevertheless, methanol addition lowered the heat release rates during the prethermal flame process.
According to previous studies, this is caused by imperfectly melted and un-melted particles of raw materials during the flame spraying process [13, 14].
The mechanism of orientation effect during the flame spread process was qualitatively analyzed in detail, and simplified expressions of flame spread rate of the two insulation materials with different orientations were deduced.
The model is a consistent extension to the steady flamelet/progress variable (SFPV) approach, and employs an unsteady flamelet formulation to describe the transient evolution of all thermochemical quantities during the flame ignition process.
The difference is attributed to the fact that in flamelet models, the dependence of scalar dissipation rate, χ, on the mixture fraction, Z, is assumed to have a constant functional relationship, usually an error function profile, which remains unchanged during the flame development process.
Distinct flame front propagation is verified during the early stages of the flame development process by both formaldehyde and OH planar laser-induced fluorescence (PLIF) imaging.
Figure 10 shows the snapshots of the flame treatment process.
While ODT captures the flame extinction process, the level of flame reignition is underpredicted, and conditional mean temperature profiles are depressed during reignition compared to the DNS.
For the flame stabilization process, however, flame propagation of the premixed branches seems to play a crucial role.
Brominated flame retardants work by releasing bromine free radicals when heated, and these free radicals scavenge other free radicals that are part of the flame propagation process.
