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Journal of Nanomaterials
Volume 2013 (2013), Article ID 198096, 11 pages
http://dx.doi.org/10.1155/2013/198096
Research Article

Self-Propagating Reactive Fronts in Compacts of Multilayered Particles

1Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
2Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
3Department of Mechanical Engineering and Materials Science, Duke University, 144 Hudson Hall, Box 90300, Durham, NC 27708, USA

Received 6 December 2012; Accepted 16 February 2013

Academic Editor: Tianxi Liu

Copyright © 2013 Ihab Sraj et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Reactive multilayered foils in the form of thin films have gained interest in various applications such as joining, welding, and ignition. Typically, thin film multilayers support self-propagating reaction fronts with speeds ranging from 1 to 20 m/s. In some applications, however, reaction fronts with much smaller velocities are required. This recently motivated Fritz et al. (2011) to fabricate compacts of regular sized/shaped multilayered particles and demonstrate self-sustained reaction fronts having much smaller velocities than thin films with similar layering. In this work, we develop a simplified numerical model to simulate the self-propagation of reactive fronts in an idealized compact, comprising identical Ni/Al multilayered particles in thermal contact. The evolution of the reaction in the compact is simulated using a two-dimensional transient model, based on a reduced description of mixing, heat release, and thermal transport. Computed results reveal that an advancing reaction front can be substantially delayed as it crosses from one particle to a neighboring particle, which results in a reduced mean propagation velocity. A quantitative analysis is thus conducted on the dependence of these phenomena on the contact area between the particles, the thermal contact resistance, and the arrangement of the multilayered particles.