2016 AIChE Annual Meeting

(320c) Modelling of RTD in a Complex Geometry Using Large-Eddy Simulation

Authors

Richard Grenville - Presenter, Philadelphia Mixing Solutions Ltd.
Jason J. Giacomelli, Philadelphia Mixing Solutions Ltd.
Residence Time Distributions (RTD) can be used to analyze mixing in continuous systems, either stirred tanks or pipe lines. The RTD is determined by measuring the concentration of a tracer in the effluent from the system being studied in response to a perturbation in the concentration at the inlet (either a pulse or step change in the tracer concentration).

In this presentation we will demonstrate how a computational fluid dynamics (CFD) large-eddy simulation (LES) has been used to characterize the RTD in a real system with a non-standard geometry and this is compared to theoretical RTDs calculated analytically.

The computed RTD shows that the vessel can be modelled successfully using the tanks-in-series approach but also determines how many tanks are required.

Modelling of the RTD with LES CFD is substantially cheaper than making measurements with the real system and this work shows that the results can be used with confidence to assess the performance of a mixed system.