1 / 9

Gas-Condensed Phase Interactions

This study explores the interactions between gas and condensed phases during combustion, focusing on the burning rate's dependence on surface temperature. We refine existing deflagration models by incorporating detailed gas-phase combustion chemistry and condensed-phase reactions. Previous work highlights energy transfer at solid surfaces and gas-liquid scattering. Our methodology includes kinetic analysis of gas-phase combustion products interacting with liquid surfaces. We aim to predict burning rates through enhanced mechanisms, underscoring the significance of evaporation and heat exchange in combustion dynamics.

tanner-hickman
Télécharger la présentation

Gas-Condensed Phase Interactions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gas-Condensed Phase Interactions Flame-Surface Heat Exchange John E. Adams Department of Chemistry University of Missouri-Columbia Columbia, MO 65211-7600

  2. Context • Early deflagration models • gasification + single reaction • no explicit chemical mechanisms • Refined models • inclusion of one or more condensed-phase reactions • detailed gas-phase combustion chemistry • gas-phase transport • phenomenological treatment of the dependence of burning rate on Ts

  3. Goal of Our Work • Predict the burning rate(depends on surface temperature) • Evaporation • Gas-phase combustion • Liquid surface heating by hot combustion products • Condensed-phase reactions

  4. Previous Work • Energy transfer at a solid surface • Many workers since the late 1960’s (polycrystalline surfaces, since 1930’s) • Adsorbate coverage, collision geometry and Ts dependences (Zhao and Adams, 1985 and 1986)

  5. Previous Work (continued) • Gas-liquid scattering—early work • Sinha and Fenn (1975) • Balooch, Siekhaus, and Olander (1986, 1988) • Nathanson group • Scattering of inert gases and smallmolecules (CH4, NH3, D2O, SF6) fromliquids and solutions having low vaporpressures (glycerol, squalane, conc.H2SO4, perfluorinated polyethers,metals, alloys) • TOF spectra, in-plane scattering fluxas a function of incident and observationangles

  6. General Features • Initial conditions • Solid layers • Liquid “layers” (periodic boundary conditions) • Gas-phase combustion products impinge on liquid surface, uniform distribution of incident angles • Kinetic energy analysis of scattered species

  7. Input/Output • I:Potential energy functions • Analytical forms (Brenner group) • “On-the-fly” • I:Combustion product analysis(Thompson group) • O:Energy transfer as a function of Ts(Rice; Miller and Anderson) • Angle-averaged energy loss to the surface • Identification of scattering components • Direct scattering • Trapping-desorption • Reactive scattering

  8. Initial Efforts • Method development and calibration • Simple Lennard-Jones fluidtest caseAr/In(6.4 and 92 kJ/mol,i=55°; 436 K)experiments byNathanson, et al. Atselected incidentenergies and angles

  9. Extensions • Energy transfer to a solution • Ar/Bi:Ga (0.02% Bi), 313-673 K • Segregation of the solute to the surface at low T • Simple molecular case • Self-sustained frozen O3 deflagration • Good models for the burning rate exist • Relatively simple mechanism (3 combustion reactions), reaction products • Possibility of reaction of incident species with the surface

More Related