The main goal of this study is to examine the possibility of using detailed three-dimensional simulations of transport of momentum, energy, and mass in horizontal single-wafer epitaxial silicon reactors in conjunction with relatively simple kinetic models to describe the reactor's performance over the entire range of operating conditions. As the SiHCl3-H-2 system is a widely used precursor for epitaxial silicon deposition in industrial applications, we have chosen to focus our model development on this system. In the development of the model we have considered the dependence of the gas properties on the gas composition as well as on the temperature. In addition, mass transport due to thermal diffusion has been considered. The accuracy of the simulation model has been examined by comparing the predicted silicon deposition rates and profiles in two commercial chemical vapor deposition (CVD) reactors with the experimentally measured values. A comparison of simulation and experimental results has indicated that a detailed transport model in conjunction with a Langmuir-Hinshelwood type kinetic model for silicon deposition accurately describes the epitaxial silicon deposition rate and deposition profile. In turn, this lumped reaction kinetic model has been used For optimization of commercially available horizontal CVD reactors for epitaxial deposition of silicon.