Numerical Simulation Of Chemical Vapor Infiltration Process Of C/C Composites

Carbon/carbon composites material has become one of the most important materialin21st century and has been mostly used in aerospace. As the prime method tomanufacture C/C composites, Chemical vapor infiltration(CVI) process involves largenumbers of physical and chemical processes that are very complex, which makes it quitedifficult to control the actual production process. Process parameters all have verysignificant impacts on CVI process such as pressure, temperature, residence time andpreform sizes, which are also directly related to the physical and mechanical properties ofC/C composites. As the CVI process deposition costs a particularly long time (more thanseveral hundred hours), and the finished products have different properties finally, thecosts substantially increased naturally. Computerized numerical simulation has beenapplied at a very wide range in various kinds of subjects in the recent decades. Numericalsimulation method utilized to simulate the CVI process not only helps to providein-depth analysis of CVI process mechanism but also offer optimized process parameters.In this paper, CVI process of C/C composites was analyzed. CVI process wasdivided into gas flow process, gas phase reactions process, surface reactions process andheat transmission process. The mathematical models were established for each process.These mathematical models have been discretized by using the finite difference methodin3D.These discrete equations could be solved by some numerical algorithms. Thecontinuous discrete solution throughout the preform could be obtained by someinterpolation algorithms.In this paper, ICVI was simulated while using the actual parameters. Thendistributions of the concentrations of four kinds of gas, density and porosity in thepreform were obtained during deposition process at each circle. Simulation results andexperimental data were compared to verify the reliability of the models. At the same timeTCVI was simulated by using the actual parameters. Distributions of temperature, concentrations of four kinds of gas, density and porosity in the preform were obtainedduring deposition process at each circle. The reliability of the model built was verified bytheoretical analysis.The program was running in Microsoft Windows XP. It was developed in VisualStudio2005, using C/C++. In order to improve the efficiency of program and utilizationof computer resources, OpenMP and Intel C++were also used.