The optimization of chemical vapor deposition processes requires an understanding of the influence of various process parameters on the deposition of thin films. A recently developed computer simulation tool provides a powerful means to develop this understanding. This paper describes the use of the computer program, FLUENT, to study the gas flow, temperature, and chemical species distributions during the deposition of CdTe. Numerical results are reported for two operating conditions for an EMCORE vertical high-speed rotating disk growth reactor and are compared to experimental data. The influence of process parameters is discussed. The effects of the addition of significant amounts of Hg (several percent) to the process gas is evaluated.