Numerical simulation of effects of reactor dimensions on isothermal CVI process of C/SiC composites

摘要

A two-dimensional axisymmetrical mathematical model taking into account the transport phenomena of momentum, energy and mass in conjunction with the infiltration induced changes of the preform structure were implemented to simulate the effects of the reactor dimension on the isothermal CVI process of C/SiC composites. The effects of the reactor inlet dimension and the reactor diameter on the concentration distribution and the time-dependent densification behaviors of C/SiC composites were studied. The reactor inlet dimension was found to impose trivial effects on the ICVI process of C/SiC composites. Calculation results show that the mean MTS molarity in preform and the global density increase firstly and then decrease with the elevating reactor diameter at any given infiltration time though the MTS molarity gradients drops gradually with the elevating reactor diameter. The preferable reactor diameter is implied to be 90 mm for the preform taken. Calculation results of the densification behavior of C/SiC composites during the ICVI process imply that the reactor diameter does not evidently influence both the rules of densification and the absolute values of the density. (C) 2008 Elsevier B.V. All rights reserved.