82

FIGURE 13.11 Application of computational flow model to simulate single-wafer CVD reactor (from Komiyama et al., 1999). (a) Standard geometry, (b) evaluation of outlet configurations.

to higher growth rate near the wall region. The computational model was further used to evolve a suitable reactor configuration to reduce the non-uniformity in growth rate. These 'virtual' experiments on computer indicated that changing the position of the reactor outlet from bottom to sidewall leads to less non-uniformities in the growth rate (Fig. 13.11b). Thus, these comprehensive computational flow models can be used to accelerate the development of better CVD reactors with minimum prototyping.

Tubular reactors are also used to carry out some multiphase reactions. Warnecke et al. (1999) reported use of a computational flow model to simulate an industrial tubular reactor carrying out a gas-liquid reaction (propylene oxide manufacturing process). In this process, liquid is a dispersed phase and gas is a continuous phase. The two-fluid model discussed earlier may be used to carry out simulations of gasliquid flow through a tubular reactor. Warnecke et al. (1999) applied such a model to evaluate the influence of bends etc. on flow distribution and reactor performance. The model may be used to evolve better reactor configurations. In many tubular reactors, static mixers are employed to enhance mixing and other transport processes. Computational flow models can also make significant contributions to understanding the role of static mixers and for their optimization. Visser et al. (1999) reported CFD

0 0

Post a comment