Forman A. Williams
University of California, San Diego
402Publications
48H-index
9,724Citations
Publications 402
#1Adam Weiss (UCSD: University of California, San Diego)H-Index: 2
#2Angel Sanchez (UCSD: University of California, San Diego)H-Index: 33
Last.Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
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Abstract The Rayleigh index of counterflow hydrogen–air diffusion flames is employed as a vehicle for quantifying inaccuracies of predictions caused by the introduction of reduced chemistry to decrease computation times. Inaccuracies of a systematically reduced 2-step mechanism, derived from a detailed 12-step mechanism for hydrogen–air systems, are small at low strain rates but become appreciable as extinction is approached.
#2Adam Weiss (UCSD: University of California, San Diego)H-Index: 2
Last.Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
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Abstract A one-step reduced mechanism for hydrogen combustion, previously developed for fuel-lean flames, is extended to apply for all equivalence ratios under near-limit conditions by taking into consideration two additional recombination steps that are important under fuel-rich conditions. It is found that the crossover temperature that appears in the cutoff factor is smaller under fuel-rich conditions. Besides improving insights, the results can be beneficial in speeding computations.
#1Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
#2Vedha Nayagam (Case Western Reserve University)H-Index: 13
Last.Vedha Nayagam (Case Western Reserve University)H-Index: 4
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#1Vedha NayagamH-Index: 13
#2Daniel L. DietrichH-Index: 13
Last.Forman A. WilliamsH-Index: 48
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Abstract A scaling analysis of burner-supported spherical-diffusion-flame extinction brought about by radiative heat loss is presented. The results are compared against earlier microgravity experimental data and unsteady numerical computations with detailed chemistry available in the literature, for normal and inverse flames. The flame diameter at extinction is shown to correlate well with the present model, in which the extinction radius scales with one-third power of gas flow rate times reacta...
#1Yuanjie Jiang (UCSD: University of California, San Diego)
Last.Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
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Abstract The aim of this study is to eliminate unimportant steps from a detailed chemical-kinetic mechanism in order to identify a skeletal kinetic mechanism that can predict with sufficient accuracy ignition delay times and laminar premixed-flame velocities for H 2 - C H 4 mixtures under conditions of practical interest in gas-turbine applications, which pertain to high pressure, high reactant temperature, and primarily lean-to-stoichiometric mixture compositions (although somewhat rich conditi...
#1Wilfried Coenen (UCSD: University of California, San Diego)H-Index: 5
#2Erik J. Kolb (UCSD: University of California, San Diego)
Last.Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
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Abstract One dozen vertically oriented thin rectangular vanes, 62 cm tall and 15.2 cm wide, were placed 27 cm from the center of heptane and ethanol pool fires in continuously fed, floor-flush pans 3.2 cm and 5.1 cm in diameter in the laboratory. The vanes were all oriented at the same fixed angles from the radial direction, for 9 different angles, ranging from 0 ∘ to 85 ∘ , thereby imparting 9 different levels of circulation to the air entrained by each pool fire. The different swirl levels wer...
#1Wilfried Coenen (UCSD: University of California, San Diego)H-Index: 5
#2Prabakaran Rajamanickam (UCSD: University of California, San Diego)H-Index: 1
Last.Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
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The interactions of the slow flow induced by the entrainment of axisymmetric jets and plumes with the surrounding geometry may result in the appearance of azimuthal swirling motion. This swirling flow evolves as it approaches the jet (or plume) as a result of the action of viscous forces on the solid surfaces bounding the fluid domain. When the initial size of the jet or plume a is much smaller than the characteristic radial distance $$R_\infty$$ at which the swirl is generated, the evolution o...
#1Jaime Carpio Huertas (UPM: Technical University of Madrid)H-Index: 8
Last.Forman A. Williams (UCSD: University of California, San Diego)H-Index: 48
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