What is Reaction mechanism?
A dataset listing the chemical species involved, their thermodynamic data, and the reactions between them with their rates.
Combustion proceeds through tens to hundreds of elementary reactions. Without a mechanism, rates and intermediate species cannot be calculated.
GRI-Mech 3.0, widely used for natural-gas combustion, has 53 species and 325 reactions.
Chosen on a Gas Source. Laplaxian identifies a mechanism by a hash of its contents, not its file name — the same name with different contents counts as a different calculation. Uploaded mechanisms are private to you by default.
It contains thermodynamic data per species (for example NASA polynomials) and a rate expression per reaction, usually of Arrhenius form:
k = A\, T^{b} \exp\!\left(-\frac{E_a}{R T}\right)
with pre-exponential factor A, temperature exponent b and activation energy E_a. Transport properties are included where needed.
Every mechanism has a validated range (fuels, temperatures, pressures). Treat results outside it with care.