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Simulation of a multiple substrate reactor for chemical vapor infiltration of pyrolytic carbon within carbon‐carbon composites
Author(s) -
McAllister P.,
Wolf E. E.
Publication year - 1993
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690390711
Subject(s) - chemical vapor infiltration , pyrolytic carbon , materials science , carbon fibers , infiltration (hvac) , hydrocarbon , composite material , chemical vapor deposition , heat transfer , reinforced carbon–carbon , mass transfer , chemical engineering , pyrolysis , chemistry , thermodynamics , porosity , composite number , organic chemistry , chromatography , nanotechnology , physics , engineering
A model for a pilot‐scale chemical vapor infiltration (CVI) reactor in which multiple substrates are densified simultaneously by carbon deposition from a pyrolyzing hydrocarbon is presented. Kinetic expressions and parameters and transport properties for carbon deposition from propylene determined from experimental studies and a single substrate CVI model are incorporated into the pilot reactor model. The two‐dimensional transport equations for heat, mass and momentum transfer are solved for the entire reactor to simulate the effects of varied operating conditions on substrate densification throughout the reactor during the CVI process. Of the conditions simulated, the reactor temperature was found to have the most significant impact on both the uniformity of densification and the process time required. As the temperature increased, the uniformity of densification decreased and the time at which pore blockage at the outer surface occurred was shortened. Increasing the hydrocarbon feed concentration shortened the process time, but did not affect the final level of densification, while the feed rate only affected CVI at intermediate times. Comparison between experimental pilot reactor results and model predictions were satisfactory at short and long times, but agreement was less satisfactory at intermediate times.