The growth of epitaxial Si on (100)-oriented Si wafers in a horizontal rapid thermal chemical vapor deposition (RTCVD) reactor has been investigated. Trichlorosilane was employed as a precursor diluted in H-2 carrier gas at 1 atm reactor pressure. The growth rates in dependence of the deposition uniformity, the input partial pressure of the precursor, and the fluid dynamics were analyzed by a three-dimensional numerical simulation. Good agreement between predicted and measured growth rates were found. Moreover, the experimental growth rates under mass transport limitation were discussed in terms of gas-phase supersaturation and its impact on the surface morphology. Finally, it is demonstrated that hydrodynamic effects in the RTCVD reactor influence strongly the Si growth in the delivery rate limited regime.