Modeling and simulation of multi-component condensed phase combustion at the meso-scale

Lee, Kibaek

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https://hdl.handle.net/2142/104836 Copy

Description

Title

Modeling and simulation of multi-component condensed phase combustion at the meso-scale

Author(s)

Lee, Kibaek

Issue Date

2019-04-18

Director of Research (if dissertation) or Advisor (if thesis)

Stewart, Donald S.

Doctoral Committee Chair(s)

Stewart, Donald S.

Committee Member(s)

• Glumac, Nick
• Lee, Tonghun
• Chaudhuri, Santanu

Department of Study

Mechanical Sci & Engineering

Discipline

Theoretical & Applied Mechans

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• numerical combustion
• meso-scale
• condensed phase material
• energetic material
• multi-component model
• deflagration

Abstract

The aim of this thesis is to develop a framework for continuum multicomponent modeling of energetic materials with applications to condensed phase combustion at the meso-scale. The meso-scale is defined to be on tens nano-meters to hundreds microns where physically distinct features, including crystal grains, defects, interfaces, etc., are found in the scale. The modeling framework includes i) a continuum formulation that is based on Gibbs free energy called the Gibbs formulation, ii) a well-posed equation of state (EOS) for condensed-phase materials, iii) reaction rate calibration based on reactive molecular dynamics (RMD) simulation results, and iv) a choice of a diffusion model. In the Gibbs formulation, the stress tensor and the temperature are assumed to be in local equilibrium; chemical changes and phase changes, however, are not. The different phases of each material must have a complete equilibrium potential. The EOS is calibrated using the Gibbs free energy form. The Hydrostatic ThermoElastic Solid, Fried-Howard Gibbs, Wide-Ranging, the fitting form in Lee et al., and ideal gas EOS are derived, modified, or converted to the Gibbs free energy form. Reaction kinetics are enormously simplified by averaging thermodynamic properties obtained from RMD simulations. Reaction kinetics can be directly measured by binned RMD simulation results. The Maxwell-Stefan diffusion model with constant diffusion coefficients is used. The mesoscale continuum model for energetic materials is formulated from a zero-dimensional model called Constant Volume Thermal Explosion (CVTEX) to a one-dimensional model which includes viscosity, thermal conductivity, mass diffusion, etc. The model is compared to RMD simulation and/or experimental results. CVTEX is compared to a RMD simulation of the ignition of γ-phase RDX in Chapter 3. A scaled continuum formulation is used to analyze nano-sized aluminum slab combustion experiments in Chapter 4. Simulation results for the 1D continuum model are compared to an RMD simulation of deflagration in a HMX nano-slab on Chapter 5.

Graduation Semester

2019-05

Type of Resource

text

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http://hdl.handle.net/2142/104836

Copyright and License Information

Copyright 2019 Kibaek Lee. All rights reserved.

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