10. Conclusion

Although there is a growing body of work on the numerical modeling of CFLs , there is still a long way to go before the pragmatic knowledge accumulated in this field over several decades can be dispensed with. The most successful fluidization models are still largely based on empirical correlations. Some of these models, such as Wirth's, attempt to explain the very existence of various fluidization regimes through the use of momentum balance equations (which amounts to an explanation of the stability of gas/solid systems). However, even these models have difficulty in accurately portraying the chaotic nature of the complex flows taking place within CFLs.

In this article, we have attempted a primarily "hands-on" presentation of the methods and models used to design circulating beds. Clearly, the experienced reader will need to resort to a broader...