Imagine a simplied piston engine that works as follows1 pure

Imagine a simplied piston engine that works as follows:(1) pure air enters the cylinder via the valves; (2) gasolineis injected directly into the cylinder; (3) all the turbulentow in the cylinder mixes the gasoline and air to thepoint where it is almost perfectly mixed; (4) the sparkplug initiates combustion.

Solution

Heat relase by cmbustion induces an increase of tempertaure .

Increase of tempertaure acclerates combustion chemistry.Due to the competition between chain branching and chain braking reactions this process is very sensitive to temperature changes.

heat release combined with tempertaure sensitive chemistry. leads to typical combustion phenomena like ignition and extinction

te maximum tempertaure in a homogenuous flow combustor is plotted as a function of the damkohler number, which here reepresents the ratio of the residence time to the chemical time. this is alled the s- shaped curve.