A Multi-Scale Simulation Approach to Study Solid Propellant Combustion and Shocked Energetic Materials
Abstract
Energetic materials release their stored chemical energy through both deflagration and detonation processes. New types of high-energy density materials (HEDM) and high-energy dense oxidizers (HEDO) are being investigated for both propulsion and ordnance applications using experiments and ?first principle simulations. Although these studies provide insight intothe characteristics of these materials at the atomistic level larger scale studies are warranted, especially since such energetic materials are also used as propellants. In the past, simulation of these heterogeneous systems have resorted to ad hoc tuning to match data. The current effort focusses on a strategy that uses inputs from ?first principle atomistic level simulations or from direct numerical simulations (DNS) and then uses homogenization to scale-up tosimulate the much larger scale of propellant combustion using a continuum solver. The current approach has been successfully applied to shock-to-detonation transition (SDT) using models for hot spots obtained from DNS data and have validated the predictions against experimental data. More recently, to incorporate more realistic random packed energetic material as in polymer-bonded explosives (PBX) a new packing algorithm has been developedthat can translate experimental images to computational model in both 2D and 3D, and also allow recreation of packing based on user specified inputs. SDT studies using this packing model and uncertainty quantification (UQ) studies are underway to assess sensitivity of predictions to input uncertainty. The same multi-scale model is now being used to simulate deflagration as in sustained combustion of a propellant in a solid rocket motor. However, for deflagration studies new modeling strategies and models have to be coupled into the solver to account for generalization of equations of state, heat transfer to the condensedphase due to gas phase combustion, propellant phase change and production of gaseous reactants, along with surface regression. Numerical tools such as adaptive mesh refinement with cut-cell (AMR-CC) and preconditioning schemes are needed (and have recently been developed) to carry out these large scale simulations with subgrid homogenization so that the subtleties of the small-scale features (cracks, voids, nano-particles) within the propellantare approximated as subgrid models within the solver. The new e -ort will combined recent developments in continuum modeling and AMR to study deflagration problems in solid propellant combustion. Canonical random packed propellants and propellant combustion as in a solid fuel rocket or ramjet are target problems and comparison with available data will be carried out for validation purpose. The combined code will also be made available toNavy researchers for their in-house applications.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 07, 2019
- Source ID
- N000141912088
Entities
People
- Suresh Menon
Organizations
- Georgia Tech Research Corporation
- Office of Naval Research
- United States Navy