Vortex rocket engine reaps the whirlwind

Lightweight combustion chamber walls stay cool because hot-burning propellant remains confined to a central cyclone.

THE INNER SURFAC ES OF ROCKET ENGINES can be subjected to extremely high heat. Temperatures as high as 3227°C can result from the powerful, thrust-generating exothermal reaction between fuel and oxidizer, which runs hot enough to melt or damage the walls of the combustion chamber.

That's why the cores of hot-running rocket engines are made of temperature-resistant materials that often incorporate networks of cooling passages. In these engine designs, vein-like ducts run with low-temperature (sometimes cryogenic) liquid propellants to carry off the heat and thus maintain structural integrity despite the violent conflagration just adjacent.