Flame chemistry; soot and NOx; detonation; pyrotechnics; laminar vs turbulent flames; emissions control; combustion kinetics; chemiluminescence and flame spectroscopy.
Combustion Chemistry
Flame chemistry fundamentals
Premixed and diffusion flames; chain-branching radicals (H, OH, O); hydrogen-oxygen explosion limits (1st, 2nd, 3rd) demonstrate kinetic…
Soot formation (PAH route)
HACA mechanism (H-abstraction C2H2-addition) builds polycyclic aromatic hydrocarbons; PAHs nucleate primary soot particles ~2 nm;…
NOx formation (Zeldovich)
Thermal NOx via extended Zeldovich (N2 + O to NO + N) above 1800 K; prompt NOx (Fenimore) via CH+N2; fuel-NOx from N-bound fuel;…
Detonation (ZND model)
Zeldovich-von Neumann-Doring 1940s: shock plus reaction zone; CJ velocity from Hugoniot tangency; detonation versus deflagration…
Pyrotechnic energetics
Black powder (KNO3 / S / C, since China 9th century); modern fireworks color from Sr (red), Ba (green), Cu (blue), Na (yellow); flash…
Laminar vs turbulent flame
Laminar flame speed S_L from thermal-diffusive balance (Mallard-Le-Chatelier); turbulent S_T enhanced by wrinkling; Damkohler-1 and Borghi…
Combustion equilibrium and adiabatic flame temperature
Adiabatic flame temperature from enthalpy balance plus equilibrium constraint; stoichiometric methane-air ~2225 K; CEA / Cantera tools for…
Combustion instability (Rayleigh)
Rayleigh criterion: instability grows when heat release in-phase with pressure; thermo-acoustic limit cycles in rocket engines,…
Combustion emissions control
Three-way catalysts (Pt / Pd / Rh) for CO + HC + NOx (1981 onward); SCR with urea (NH3) reduces diesel NOx; particulate filters (DPF /…
Flame spectroscopy and chemiluminescence
OH (309 nm), CH (431 nm), C2 Swan (516 nm), CO2 (broad blue) emission identify flame structure; LIF (laser-induced fluorescence) quantifies…
Combustion kinetics (GRI-Mech)
GRI-Mech 3.0 (53 species, 325 reactions) is the standard methane-oxidation mechanism; San Diego, USC, AramcoMech extend to diesel and…
Fischer-Tropsch and bio-fuels combustion
FT (Fischer-Tropsch 1925) syngas to alkanes drives synthetic-fuel and gas-to-liquids economy; bio-fuels (ethanol, biodiesel, HVO, SAF)…
Flammability limit (Le Chatelier)
Le Chatelier 1891 mixing rule: flammability limit of fuel mixture = 1 / sum(y_i / LFL_i); LEL ~5% for hydrocarbons in air; UEL ~15%;…
Autoignition (cetane / octane number)
Autoignition temperature is fuel + oxidizer + pressure dependent; cetane-number 40+ favors compression-ignition (diesel); octane-number…
Hydrogen combustion flame speed
H2 + O2 has very high laminar flame-speed (S_L ~3 m/s vs 0.4 m/s for hydrocarbons) due to high diffusivity + chain-branching; wide…
Flameless / MILD combustion
Cavaliere-de-Joannon 2004 MILD = Moderate Intermittent Low-oxygen Dilution: oxidizer pre-heated above auto-ignition + diluted to <5% O2;…
Flame quenching distance
Davy 1815 lamp: flame cannot propagate through gap below ~2 mm for hydrocarbons (Peclet ~50); foundation of flash-arrestors + fire-safety…
Mass burning rate (pool fire)
Hoyer-Hottel 1959: liquid-fuel pool-fire mass-burning-rate scales m_dot_inf (1 - exp(-k beta D)) with diameter D; saturates at…