CFD Modelling of Roughness in ALM Event

4th Oct

CFD Modelling of Roughness in ALM Event

The Centre for Modelling & Simulation (CFMS) will be holding a facilitated breakfast brainstorm event on the topic of CFD modelling of roughness in ALM products. Taking place on 4th October 2016, 09.00 - 11.00, the event will be chaired by David Standingford, Lead Technologist, CFMS.

 Additive layer manufacturing (ALM) is a revolutionary new manufacturing technique that creates “near net shape” (or no waste) manufacture for a range of material types including metals.  ALM can take many forms, but a popular method for manufacturing complex metal products is the Powder Bed Fusion technique, where layers of metal powder are progressively added to a container and laser-fused to create a solid component.  When complete, the spare powder is removed; any support structures removed and the external surfaces finished.

 While the external surfaces are generally smoothed to remove the rough surface produced by ALM, it is very difficult to finish the internal surfaces (particularly for complex shapes).  Whether this is an advantage or a disadvantage depends very much on the application. Roughness can induce transition to turbulence – which in some cases can delay separation from a curved surface. Increased turbulence can be a source of energy loss in a system as well.  Rough internal surfaces can be sharp, and ALM roughness is anisotropic – i.e. the layering process leads to a pattern on the surfaces.

 The fluid dynamics effects for components such as fluid cooling grilles, vents, pipes or gauge housing units depend upon the rate and state (laminar or turbulent) of the fluid flow. Computational fluid dynamics (CFD) methods for dealing with surface roughness do exist (roughness heights, lengths) but little work has been done to date to standardise these for ALM product applications – particularly considering the anisotropy.

 So what happens when there are multiple components manufactured in the same production run, but with different orientations? Can design problems be fixed by choosing particular orientations?  Could we detect internal damage or non-conformity using fluid flow diagnostics? Is there a characterisation model for ALM roughness that can be parameterised to cover the range of powders and processes in common use? Could we design some physical experiments to validate our numerical models? What other effects might there be?

 Taking place between 09.00 - 11.00 hrs, we invite you to join us for a breakfast brainstorming session on 4th October 2016, to explore these ideas.  If there is enough common interest in this area, the opportunity to develop output into a potential project will be explored.  To register for the event, complete the form below - places will be limited. We hope to see you there!


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Bristol & Bath Science Park

Dirac Crescent

Emersons Green


BS16 7FR

Start time

9:00 4/10/2016

End time

11:00 4/10/2016

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