Selective epitaxial growth (SEG) of silicon has become a key element in the development of semiconductor integrated circuits for its good electrical properties and advantages in building submicron dimensions necessary to meet the scale-down demands. Silicon epitaxy can be achieved in various systems. Among these, chemical vapor deposition (CVD) epitaxy is the most important technology due to its advantages over other techniques. Numerical modeling has been carried out to simulate transport phenomena and epitaxial silicon growth in a planetary chemical vapor deposition (CVD) reactor for the SiH2Cl2-H2-HCl system. In the present paper, a chemical reaction model is validated using experimental results and published results obtained in pancake reactor for the same gas mixture. Governing equations of continuity, momentum, energy and chemical species are solved using commercial Computation Fluid Dynamics (CFD) software ANSYS FLUENT. The agreement between the simulation predictions of proposed model and the experimental is satisfactory. The chemical model can be a valuable and time saving tool in the analysis of the process in the reactor, and to study the effects of various operating conditions on the growth rate and uniformity.