OCR Text |
Show - 8 - Cb is expressed as (12) where , is the ratio of specific heats of the burned gas. Further, assuming that P and , are constan t, P b cb can be expressed as Then, Eq.(11) can be rewritten as 1 2 Pb . (13) (14) If the flame temperatures of methane-air mixtures are assumed in the range of 1 1700 K rv 2000 K, Pb 4 varies less than 5 % and could be assumed constant. P (_tL _ 1) varies 20 % in this range and it also could be thought to be constant. Pb Then, the dependency of P o on c, StL' U is approximately expressed as, (15) The value of c seems to be proportional to the kinetic energy of the flow t urbulence of unit area on the flame front, because one averaged unit flame front deformation could be thought to consum one unit of kinetic energy of the flow turbulence for a limited range of flow v locities, i.e., (16) |