Time-Dependent Computational Studies of Flames in Microgravity
Title | Time-Dependent Computational Studies of Flames in Microgravity PDF eBook |
Author | National Aeronautics and Space Administration NASA |
Publisher | |
Pages | 111 |
Release | 2018-11-13 |
Genre | |
ISBN | 9781731262950 |
The research performed at the Center for Reactive Flow and Dynamical Systems in the Laboratory for Computational Physics and Fluid Dynamics, at the Naval Research Laboratory, in support of the NASA Microgravity Science and Applications Program is described. The primary focus was on investigating fundamental questions concerning the propagation and extinction of premixed flames in Earth gravity and in microgravity environments. The approach was to use detailed time-dependent, multispecies, numerical models as tools to simulate flames in different gravity environments. The models include a detailed chemical kinetics mechanism consisting of elementary reactions among the eight reactive species involved in hydrogen combustion, coupled to algorithms for convection, thermal conduction, viscosity, molecular and thermal diffusion, and external forces. The external force, gravity, can be put in any direction relative to flame propagation and can have a range of values. A combination of one-dimensional and two-dimensional simulations was used to investigate the effects of curvature and dilution on ignition and propagation of flames, to help resolve fundamental questions on the existence of flammability limits when there are no external losses or buoyancy forces in the system, to understand the mechanism leading to cellular instability, and to study the effects of gravity on the transition to cellular structure. A flame in a microgravity environment can be extinguished without external losses, and the mechanism leading to cellular structure is not preferential diffusion but a thermo-diffusive instability. The simulations have also lead to a better understanding of the interactions between buoyancy forces and the processes leading to thermo-diffusive instability. Oran, Elaine S. and Kailasanath, K. Unspecified Center ALGORITHMS; EARTH GRAVITATION; EXTINGUISHING; FLAME PROPAGATION; MATHEMATICAL MODELS; MICROGRAVITY; PREMIXED FLAMES; TIME DEPENDENCE; BUOYANCY; CONVECTION; GAS MIX...
Time-dependent Computational Studies of Premixed Flames in Microgravity
Title | Time-dependent Computational Studies of Premixed Flames in Microgravity PDF eBook |
Author | |
Publisher | |
Pages | 104 |
Release | 1993 |
Genre | |
ISBN |
Microgravity Science and Applications Program Tasks
Title | Microgravity Science and Applications Program Tasks PDF eBook |
Author | United States. Office of Space Science and Applications |
Publisher | |
Pages | 280 |
Release | 1991 |
Genre | Alloys |
ISBN |
Microgravity Science and Applications Program Tasks
Title | Microgravity Science and Applications Program Tasks PDF eBook |
Author | |
Publisher | |
Pages | 320 |
Release | 1992 |
Genre | Fluid dynamics (Space environment) |
ISBN |
Microgravity Science and Applications Program Tasks, 1990 Revision
Title | Microgravity Science and Applications Program Tasks, 1990 Revision PDF eBook |
Author | |
Publisher | |
Pages | 280 |
Release | 1991 |
Genre | Fluid dynamics (Space environment) |
ISBN |
NASA Technical Memorandum
Title | NASA Technical Memorandum PDF eBook |
Author | |
Publisher | |
Pages | 492 |
Release | 1994 |
Genre | Aeronautics |
ISBN |
Scientific and Technical Aerospace Reports
Title | Scientific and Technical Aerospace Reports PDF eBook |
Author | |
Publisher | |
Pages | 652 |
Release | 1992-11 |
Genre | Aeronautics |
ISBN |