A Computational Model for Chemical Vapor Infiltration

这个小企业创新研究第一阶段项目是针对化学气相渗透（CVI）的综合计算模型的开发和验证。它涉及一个宏观模型，描述了在多孔预制件的传输过程。在宏观模型中所需的预成型件的宏观性质是从微观模型确定的，在该微观模型中，对由矩形横截面的纤维组成的广义单元格中的流体流动、传热和传质进行详细计算。第一阶段工作的技术目标是证明二维渗透过程模型的关键成分的有效性。将审议的具体专题是：（a）验证等效晶胞方法，（B）评估作为密度的函数的预成型件特性，（c）通过证明所提出的模型的结果与从考虑所有几何细节的完全数值模拟获得的结果相比良好，验证二维预成型件的总体模型，以及（d）案例研究，以证明所提出的模型作为设计/优化工具的有用性。所提出的计算模型的使用将导致更低的制造成本和陶瓷复合材料的使用增加。

This Small Business Innovation Research Phase I project is directed toward the development and validation of a comprehensive computational model for chemical vapor infiltration (CVI). It involves a macro model that describes the transport processes in a porous preform. The macroscopic properties of the preform that are needed in the macro model are determined from a micro model in which detailed calculations are made for fluid flow, heat transfer, and mass transfer in a generalized unit cell comprising of fibers of rectangular cross section. The technical objectives of the Phase I effort will be to demonstrate the validity of the crucial ingredients of the model for two-dimensional infiltration process. The specific topics to be considered are: (a) validation of the equivalent unit cell approach, (b) evaluation of preform properties as functions of the density, (c) validation of the overall model for a two-dimensional preform by demonstrating that the results of the proposed model compare well with those obtained from full numerical simulation that accounts for all geometric details, and (d) a case study to demonstrate the usefulness of the proposed model as a design/optimization tool. Use of the proposed computational model will lead to lower manufacturing cost and increased use of ceramic composite materials.