Leakage flow simulation in dynamic seals from 3D-printing

Additive manufacturing (AM) technologies make strong progress in these years and impact seals as well. However the surface quality of AM seals is typically lower compared to seals from conventional production. For example Fused Filament Fabrication produces parts with a regular string-like surface structure. This structure is generated from a thin moving nozzle that extrudes melted filament material to strings. The size of the surface structure is in the order of the fluid film thickness of a dynamic rod seal. A fluid-structure interaction (FSI) with fully coupled Navier-Stokes equations analyses the fluid flow between seal and rod. It shows that a periodically fragmented contact, which is generated by FFF, impacts sealing properties of the dynamic seal. A simulation-based comparison between conventional seals and those from FFF manufacturing shows e.g. consequences for leakage flow through the seal gap.