The laminar mixed convection flow and heat transfer in a Chemical Vapor Deposition reactor are studied through numerical simulation. It is found that the non-linear interaction between forced and free convection may lead to the existence of multiple stable flows. Arclength continuation techniques, implemented within the framework of the finite volume discretisation, have been applied to determine the causes for this multiplicity. It is shown that the relevant dimensionless groups are Gr/Re and Re x Pr. When both these groups are sufficiently large, multiple stable Rows may exist. (C) 2001 Elsevier Science Ltd. All rights reserved.