Convective heat transfer and flow stability in rotating disk CVD reactors

摘要

The flow and heat transfer of NH3 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 NH3. 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 NH3 is less stable than that of He as MCP(sub d) is increased for MCP(sub w) = 0 and Re(sub omega) = 314.5.