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Moshe Matalon , Caterpillar Professor D . Scott Stewart, Shao Lee Soo Professor

Continuum Modeling and Simulation of Microscopic, Multi-phase, Reactive Processes of Reactants at the Nano- and Microscale. Moshe Matalon , Caterpillar Professor D . Scott Stewart, Shao Lee Soo Professor matalon@illinois.edu (217) 244 8746 dss @ illinois.edu (217) 332 7947

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Moshe Matalon , Caterpillar Professor D . Scott Stewart, Shao Lee Soo Professor

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  1. Continuum Modeling and Simulation of Microscopic, Multi-phase, Reactive Processes of Reactants at the Nano- and Microscale Moshe Matalon, Caterpillar Professor D. Scott Stewart, Shao Lee Soo Professor matalon@illinois.edu (217) 244 8746 dss@illinois.edu(217) 332 7947 Sept 18th, 2014

  2. Overview/Outline of Recent Illinois work (2103-14) (for the Sept 18th talk) • Detailed analysisof a generic three-components counterflowflame supported by condensed phase, temperature dependent reaction and diffusion processes • (with applications propellant and energetic material ingredients to Ti + B, Al + AP, Al + Binder, Ti + Si and alike) • B) Model development that allows consideration of more complex • reaction diffusion pathways in condensed liquids/solids • (with more than 3 species and with phase transition) • C) Initial modeling steps for a theory of condensed phase combustion front comprised of the dynamic combustion ofseparated reactants associated with the manufactured microstructure. • (consideration of coherent rapid phase change and combustion in localized spots and the effective front behavior)

  3. Multi-component, model for separated reactants Condensed phase diffusion flames

  4. A) Detailed analysis of a generic three-components counterflow flame • Counterflowsub-models: • Analysis of a generic three-components counterflow flame configuration of the form • R1+ R2→ Products • An important aspect that distinguishes these types of problem from classical • gaseous combustion is the diffusion properties of the reactants. • The use of generalized Fickian diffusivities requires the determination of the • diffusion coefficients and their dependence on the (more fundamental) binary • diffusivities. • These generally are concentration and temperature dependent. • We are examining a hierarchical of complexities starting with • (i) constant diffusion coefficients, • (ii) coefficients that are concentration dependent and • (iii) coefficients that are also highly temperature-dependent.

  5. B) Model development that allows consideration of more complex reaction diffusion pathways in condensed liquids/solids • First example: Formulation of more complex condensed phase • reaction/diffusion mechanisms (Al, CuO burning) • Overall 2 Al + 3 CuO => Al2O3 + 3 Cu • EIGHT (8) condensed phase species • Al(s) Al(liq)CuO(s)CuO(liq) Cu(s) Al(s) Al(liq) Al2O3(s) Al2O3(liq) • Simplified multicomponent diffusion • Phase change • Chemical reaction

  6. C) Model of condensed phase combustion front made of separated reactants associated with the manufactured microstructure. Exp Results: Shown forstoichiometric Al/CuOthermite (N. Glumac UIUC Glumac-Stewart DTRA grant) • Imaging and video sequences show progression of the reaction • Initial densification can be observed • Propagation and flame speed can be examined

  7. Test 6 Al-CuO Stoich Movie and details to be added

  8. Extraction of a Slice of the observed view field, Test 6 (CuO/Al) Cut-outs images that correspond to the image in the yellow section. The red circle at 30.43 ms isolates a single rapid ignition/extinction even on the scale of 100 micron

  9. Cut-outs of images of a approximately 1.5 mm x 2 mm region that show a rapidignition/extinction event. The values image intensity of the bright spot is approximately but shown at the measure elapsed time. Evident of a reaction diffusioncontrolled condensed phase flame ignition Thermal time scale (millisec)Chemical time scale (~ 10 to 100 μsec) To be compared with model calculations

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