In February, Fluent and Aspen Technology, Inc. announced the formation of a strategic technology initiative to establish an integrated plan for providing comprehensive design and simulation tools for the chemical, petrochemical, pharmaceutical, and power industries. The need for integration between CFD software and process simulation software has become apparent, as use of these tools has become widely accepted in the chemical process industry. Use of process simulation software is now standard practice for process conceptualization, design, engineering, and operation. CFD is also widely used for process design, development, optimization, and in particular, for applications involving chemically reacting and multiphase flows. The increase in the use of these tools may be attributed to the dramatic increase in low cost computational power, combined with ongoing improvements to the numerical models available.

A number of activities have taken place since the initiative was launched. In March, the Department of Energy awarded $1.5 million to Fluent, AspenTech, ALSTOM Power, Intergraph, and West Virginia University to integrate CFD, flowsheet modeling, and plant layout tools. At the U.S. Fluent Users' Group Meeting in Danvers, MA in June, the first practical demonstration of the integration of CFD into an Aspen Plus flowsheet simulation was presented. A roundtable discussion followed the presentation to get a first-hand account from Fluent users about their need for integrating process simulation tools and CFD.

In August, a presentation entitled "Improving Reactor Modeling in Sequential-Modular Process Simulation Using CFD," coauthored by Fluent and AspenTech engineers, was presented at the Chemical Reaction Engineering VII Conference on Computational Fluid Dynamics. The paper outlined some of the strategies for the integration of CFD with process simulation technology. These included:

• coupling the unit operations, which involves the exchange of input-output stream information between the simulation tools, each with a distinct solution domain (i.e. different unit operations in a process flowsheet);

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Coupling the units – using FLUENT CFD models as unit operations in an Aspen Plus flowsheet simulation

• coupling the physics, which involves extremely tight cou- pling between the simulation tools, each modeling the same solution domain using different approximations; and
• coupling the physical property modeler, which involves the use of high fidelity property modeling tools from the flowsheet simulator in the CFD simulation.

The paper reviewed the advantages and disadvantages of each strategy and demonstrated the coupling that has been implemented to date.

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