Nitrous Oxide: Oxidizer and Promoter of Hydrogen and Hydrocarbon Combustion

This Review examines the gas-phase oxidations of hydrogen and other fuels (ammonia, hydrazine, hydrocarbons) with nitrous oxide, running as self-ignitions, deflagrations, or detonations. Taking into account the main feature of nitrous oxide, i.e., its ability to decompose exothermally, this Review summarizes also the conditions determining an explosive evolution of N2O decomposition, and the characteristic parameters of this process, as self-ignition or after ignition by local energy sources. For fuel–nitrous oxide explosive combustion, this Review is focused on conditions where the explosive combustion takes place (flammability limits, minimum ignition energy) or it is quenched (quenching distance, Maximum Experimental Safe Gap) and on the characteristic properties of explosion development and propagation. These properties are separately examined for deflagrations and detonations. The DDT (Deflagration-to-Detonation) process is also taken into account, because it occurs in most technical applications of fuel–N2O combustion in enclosures. This Review is completed by a discussion of processes where nitrous oxide is promoter of fuel–oxygen or fuel–air explosive combustion.