# Combustion Combustion is rapid [[Redox|oxidation]] that releases [[Energy]] as heat and light. On this spine it is the founding event of the reaction canon: [[Hydrogen]] burning in [[Oxygen]] to give [[Water]], the cleanest combination reaction there is and the one the whole [[WT!Thury_Hydrodynamics_Compendium|compendium]] is indexed on. ## Mixing is the rate-limiting step A flame is not a chemistry problem alone — it is a [[Fluid_dynamics|fluid]] problem wearing chemistry's clothes. Fuel and oxidiser must meet at molecular scale, and what delivers them is [[Turbulence]] and [[Diffusion]], which is why combustor design is largely [[Eddy_(fluid_dynamics)|mixing]] design and why a [[Kelvin–Helmholtz_instability]] in the shear layer sets flame stability. Hydrogen's wide flammability range and high flame speed make it easy to ignite and hard to contain, which is the safety case behind every [[Hydrogen_production|hydrogen]] handling standard. Run the reaction slowly and controlled and it is a [[Fuel_cell]] instead. **Reads with:** *General Chemistry: Principles, Patterns, and Applications (2011)* — [OTL record](https://open.umn.edu/opentextbooks/textbooks/general-chemistry-principles-patterns-and-applications) · [download](https://www.saylor.org/site/textbooks/General%20Chemistry%20Principles,%20Patterns,%20and%20Applications.pdf). Seeded from the Thury Hydrodynamics Apex Spine book shelf. **On the spine:** [[Oxyhydrogen]] · [[Redox]] · [[Hydrogen]] · [[Oxygen]] · [[WT!Thury_Hydrodynamics_Compendium]]. <!-- COMPENDIUMLINK:BEGIN g19 — generated from _registry/plans/THURY_COMPENDIUM_SECTIONS.md; do not hand-edit inside --> **Part of the [[WT!Thury_Hydrodynamics_Compendium|Thury Hydrodynamics Compendium]]** — main article for section 9, *Combustion*. Related sections: [[Turbulence]] · [[Electrolysis_of_water]] · [[Fuel_cell]]. <!-- COMPENDIUMLINK:END --> <!-- THURYSIM:BEGIN g21 — Thury Compendium microsim (framework build, specs/sims/Combustion.json); do not hand-edit inside --> **Microsim — three.js (Wikitube framework):** *Combustion* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/thury/Combustion.html" data-title="Combustion"></div> *Built from `MICROSIM_GUIDE/specs/sims/Combustion.json`; part of the [[WT!Thury_Hydrodynamics_Compendium|Thury Hydrodynamics Compendium]] set.* <!-- THURYSIM:END --> ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Combustion) : [Wikitube](https://en.wikitube.io/wiki/Combustion) ## Previous hub tags Hubs: `Life_Physics`, `Systems`. Portals: [[PORTAL_Thury_Hydrodynamics_Apex_Spine]], [[PORTAL_Hydrogen]], [[PORTAL_Oxygen]]. --- *Apex Spine wave · 2026-09-10 · stub · microsim layer deferred.*