Accession Number : ADA182127

Title :   Time-Dependent Simulations of Laminar Flames in Hydrogen-Air Mixtures.

Descriptive Note : Memorandum rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Kailasanath,K ; Oran,E S

PDF Url : ADA182127

Report Date : 17 Jun 1987

Pagination or Media Count : 16

Abstract : We have examined two fundamental problems in premixed laminar flames using a detailed, time-dependent, one-dimensional model. In the first problem, we examined the relative importance of thermal conduction, thermal diffusion, and ordinary diffusion in determining the burning velocities of laminar hydrogen-air flames. Three cases were examined in detail: a fuel-lean mixture, a stoichiometric mixture, and a fuel-rich mixture. Our general conclusion from this study is that both ordinary diffusion and thermal conduction are necessary to quantitatively describe flame propagation in a hydrogen-air mixture. Their relative importance, however, varies as we go from fuel-lean to fuel-rich hydrogen-air mixtures. In the second problem, we considered the behavior of flames in fuel rich hydrogen-air mixtures near the experimentally observed flammability limit. The effects of gravity, stretch and external heat losses were eliminated in the numerical simulations. The results suggest wider flammability limits than those observed experimentally under normal gravity conditions. The simulations also indicate that there may be a limit due to chemical kinetic considerations alone.

Descriptors :   *FLAMES, *COMBUSTION, *AIR, *HYDROGEN, *LAMINAR FLOW, GRAVITY, FLAME PROPAGATION, FLAMMABILITY, LIMITATIONS, MIXTURES, VELOCITY, EXTERNAL, HEAT LOSS, FUELS, ONE DIMENSIONAL, STOICHIOMETRY, THERMAL CONDUCTIVITY, SIMULATION, TIME DEPENDENCE, NUMERICAL ANALYSIS, MIXING, THERMAL DIFFUSION

Subject Categories : Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE