2.6

## Hanyang University

• When the chemical reaction is combustion reaction, heat is evolved from the reaction. This heat might be used to raise the temperature of the system including reaction products and the remained reactants.
• When the combustion reaction is conducted under adiabatic conditions, the highest temperature can be achieved since there is no heat loss to surrounding.
• The highest temperature that can be achieved is called is the adiabatic flame temperature.
• Take the reaction chamber as the system. The First law of thermodynamics for a steady-state reaction chamber is

($dU$ + $ΔPE$ + $ΔKE$)$sys$= 0 = ∑($H$$i$)$m$$i$ − ∑($H$$o$)$m$$o$ + δ$Q$ + δ$W$

No work is done on or by the system and the system is adiabatic.     (W=Q=0)

∑($H$$i$)$m$$i$ = ∑($H$$o$)$m$$o$

From here, the adiabatic flame temperature can be calculated.