Convective heat transfer and flow stability in rotating disk CVD reactors

The flow and heat transfer of NH{sub 3} and He have been studied in a rotating disk system with applications to chemical vapor deposition reactors. Influence of the important operating parameters were studied numerically over ranges of the primary dimensionless variables: (1) the spin Reynolds number, Re{sub {omega}}, (2) the disk mixed convection parameter, MCP{sub d}, and (3) a new parameter, the wall mixed convection parameter, MCP{sub w}. Inlet velocities were set to the corresponding infinite rotating disk asymptotic velocity. Results were obtained primarily for NH{sub 3}. Results show that increasing Re{sub {omega}} from 314.5 to 3,145 increases the uniformity of the rotating disk heat flux and results in thinner thermal boundary layers at the disk surface. At Re{sub {omega}} = 314.5, increasing MCP{sub d} to 15 leads to significant departure from the infinite disk result with nonuniform disk heat fluxes and recirculating flow patterns. At Re{sub {omega}} = 3,145, the results are closer to the infinite disk for MCP{sub d} up to 15. For large values of MCP{sub w}, the flow recirculates and there is significant deviation from the infinite disk result. The influence of MCP{sub w} on flow stability is increased at larger MCP{sub d} and lower Re{sub {omega}}. The results show that because of variable transport properties, the flow of NH{sub 3} is less stable than that of He as MCP{sub d} is increased for MCP{sub w} = 0 and Re{sub {omega}} = 314.5