I have this formula for flame speed from way back when but don’t know source or method any more. Is still being used by ex-employer successfully for checking burners on town-gas mixtures. I don't work there anymore and don't have that part of the file with me, just the calc method! Not an in house method, was sourced from literature.
For a mixture of H2, CO, CO2, CH4, N2, Ar, C3H8. (The C3H8 volfrac was at low levels ,<3 vol%, and used to represent all HC heavier than CH4 in the gas)
Flame speed factor :
FFTot = Volfrac H2 * 339 + Volfrac CO * 61 + Volfrac CH4 * 148 + volfrac C3H8 * 398
Molar stochiometric air demand factor :
AFTot = Volfrac H2 * 2.39 + Volfrac CO * 2.39 + Volfrac CH4 * 9.55 + Volfrac C3H8 * 23.87
Volfrac inerts :
Volfracinerts = Volfrac CO2 + Volfrac N2 + Volfrac Ar
FS = FFTot / (AFTot + 0.05*(Volfracinerts) + 1 – 18.8 * VolfracO2)
Using this method, yields hydrogen as a flame speed of 100.
NB : Volfrac O2 was always zero for our mixes.