Advanced Thermodynamics for Engineers, 2nd Edition

where

p ¼ pressure (bar)

T ¼ temperature (K)

u

[

¼ laminar flame speed (m/s).

It can be seen from Eqn (15.11) that the effect of pressure on flame speed is very small, as sug-

gested above. Figure 15.7 shows how the laminar flame speed increases with reactants temperat ure: it

has been assumed that the adiabatic temperature rise remains constant at 2000 K, which is approxi-

mately correct for a stoichiometric mixture. It can be seen that the speed increases rapidly, and reaches

a value of around 4 m/s when the reactants temperature is 1000 K. This is an increase of about a factor

of 8 on the previous value which would reduce the combustion duration to about ...