Abstract
An investigation into the automatic design optimisation of steady and unsteady fluid flow systems, using Computational Fluid Dynamics, is described.Steady flow 3D CFD models of simple pipe-volume-pipe networks were developed and validated against the results from experimentally derived pressure measurements and PIV imaging techniques. An optimisation methodology was outlined before conducting design optimisations of the baseline CFD models, with the aim of reducing the pressure loss across
the systems.
To facilitate the optimisation process the CFD models were reduced to 2D as this resulted in a 95 % reduction in the CFD run-time and a similar saving in the run-time of the subsequent design optimisations. While the 3D CFD models were shown to be accurate throughout the investigations, the 2D models would consistently under-predict losses because of the wall boundary simplifications. However, this was not judged to be an impediment to this use in the optimisation.
The optimised designs were validated by repeating the steady flow experiments. They showed significant improvement in steady flow performance, with a 5 % reduction in pressure loss in one case and a 15 % reduction in another.
A further study was then carried out to compare the effect of the baseline and optimised designs on the transmission of unsteady gas dynamic pressure waves. An unsteady pulse rig was used to generate repeatable pressure waves for experimental investigations. Data in the form of PIV images and pressure traces provide the focal point for a discussion of potential objective functions for future design optimisation studies of transient fluid systems. The results clearly showed that the geometrical design affects the characteristics of the pressure waves. It was concluded that the selection of an objective function would depend on the application of the system and the desired wave characteristics. Nevertheless, a selection of objective functions was suggested for typical applications.
| Date of Award | Jul 2010 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Geoff Cunningham (Supervisor) & David Thornhill (Supervisor) |
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