An analytical model of the transient ablation of polytetrafluoroethylene layers

A reactive molecular dynamics study of hyperthermal atomic oxygen erosion mechanisms for graphene sheets

“…This atomic oxygen density, for instance, with a combination of the orbital velocity of 8 km/s for the spacecraft would yield an oxygen flux of 10 19 atoms/(m 2 s) at a mean collision energy of 5 eV [3]. Thermal protection materials would undergo complex physical and chemical response to such conditions including surface catalysis and ablation reactions [4][5][6][7]. Aiming to identify the material damage and characterize the aerodynamic heating due to the collisions of hyperthermal atomic oxygens accurately, a fundamental understanding of the surface catalysis and ablation reaction mechanisms for carbonbased materials is essential for thermal protection system design of with space based applications.…”

A kinetic expression for the pyrolytic decomposition of polytetrafluoroethylene

“…Carrol and Manche [8], using a differential technique on a non-disclosed PTFE sample type, reported a discontinuity in the mass-loss data at 520 8C, determined two activation energies without corresponding prewww.elsevier.com/locate/fluor Available online at www.sciencedirect.com Journal of Fluorine Chemistry 129 (2008) 314-318 exponential factors, with two discrete rates, both displaying zero-order kinetics. Holzknecht reported an analytical solution for evaluating evaporation rates and one-dimensional temperature profiles for PTFE particles passing through a hightemperature plasma [9]. Of importance, however, the ablation rate was not determined in the experimental work; rather historical rate data, based on first-order kinetics, were used.…”

“…Despite the fact that work on PTFE depolymerisation has been extensively reported since shortly after the first discovery of the material, and despite the fact that particle size effects are well known in thermogravimetric analysis (TGA) [4] this group of authors found the available literature data, e.g. [5][6][7][8][9][10][11] to be inadequate for design purposes and, crucially, not to address sample geometry.…”

Numerical Investigation on Laser Ablation Characteristics of PTFE in Advanced Propulsion Systems

“…And Arai [2, 3, and 4] applied the model to the axisymmetric model of PTFE and investigated the transient ablation of PTFE in intense radiative and convective environments. Besides, in similar to the work of Holzknecht [5], the influence of the decomposition energy absorption and recombination energy release in ablation process is considered. And Stechmann [6] modified the ablation model for use in simulated PPT operations and developed a volume fraction method for capturing the moving interface between the semi-crystalline and gel phases.…”