Title page for ETD etd-08112010-163505


Type of Document Master's Thesis
Author Mandal, Anirban
Author's Email Address amanda2@lsu.edu,anirban.ind@gmail.com
URN etd-08112010-163505
Title Computational Examination of Compaction Wave-Boundary Interaction in Granular Explosive
Degree Master of Science in Mechanical Engineering (M.S.M.E.)
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Gonthier, Keith A. Committee Chair
Guo, Shengmin Committee Member
Nikitopoulos, Dimitris E. Committee Member
Pang, Su-Seng Committee Member
Keywords
  • Granular HMX
  • Accidental initiation
  • Dynamic compaction
  • Granular energetic solid
  • Oblique reflection
  • Normal reflection
  • Rate-dependent compaction
  • Inelastic compaction
  • Compression
Date of Defense 2010-08-06
Availability unrestricted
Abstract
Interactions between initially planar, piston supported compaction waves in heterogeneous energetic solids and macro-scale rigid boundaries were computationally examined for a wide range of piston impact speeds (20 ≤ Up ≤ 500 m/s) and initial solid volume fractions of the material (0.73 ≤ ϕ0 ≤ 0.90). The response of the material was described by a continuum theory that accounts for both elastic and inelastic compaction in a thermodynamically consistent manner. Initial conditions were imposed by interpolating the spatial structure of one-dimensional steady compaction waves onto two-dimensional domains considered in this study. For a planar wedge boundary, the peak solid pressure (Ps), dissipative heating rate (ėc) and bulk temperature rise (ΔT) at the boundary increased when wedge angle θ was increased from 0 to a critical value (60 ≤ θc ≤ 65) as the flow transitioned to a single Mach reflection (SMR) from a von Neumann reflection (vNR); these quantities decreased when θ was further increased due to flow transition to a regular reflection (RR) from a SMR for ϕ0 = 0.85 and Up = 500 m/s. Locations of the peak Ps, ėc and ΔT were predicted to be removed from the wedge tip for a vNR and a SMR, but near the wedge tip for a RR. Qualitatively similar predictions were obtained for 0.73 ≤ ϕ0 ≤ 0.90 and Up ≥ 150 m/s. For a semi-circular boundary, the initial RR configuration transitioned to a SMR for all cases. For 0.73 ≤ ϕ0 ≤ 0.90 and Up ≥ 150 m/s, peak values of Ps, ėc and ΔT were predicted at a location removed from the stagnation point. For both wedge and semi-circular boundaries, dissipative heating at the boundary was dominated by rate-dependent compaction. To aid in the development of a bulk-scale combustion sub-model, bulk-scale predictions were compared to locally averaged meso-scale predictions. Bulk-scale and averaged meso-scale predictions showed good agreement, provided that the averaging area size was suitably selected.
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