Jafari, Davoud

Wits, Wessel W.

English

University of Twente Research Information

ENHANCING THERMAL MANAGEMENT APPLICATIONS THROUGH POROUS STRUCTURES FABRICATED BY SELECTIVE LASER MELTINGDavoud Jafari, Wessel W. WitsFaculty of Engineering Technology, University of Twente, Enschede, NetherlandsA rectangular-shaped stainless steel 316L porous structure is additively manufactured by selective laser melting (SLM). Effective thermal conductivity to the porous structure have been experimentally analyzed. The experimentally obtained values of thermal conductivity do not correspond well with correlations available in the literature.The experimental results show that SLM technology can be used to fabricate porous structures for heat pipes technology. Corresponding author Wessel WitsAssistant ProfessorDepartment of Design, Production and Management+31 53 489 2266w.w.wits@utwente.nlThe effective thermal diffusivity is in the range of 1.8~2.2 W/m·K in vacuum condition, ~3 W/m·K for ethylene glycol and ~6 W/m·K for water, thusobserving high sensitivity to the interstitial fluid.A comparison of the experimental results with available correlations in the literature shows the effective thermal conductivity is between the upperand lower Maxwell model, albeit with a fairly large margin.Spherical powder and the build structureThe fabricated sample The thermal conductivity measurement set-up0246820 40 60 80keff [W/m K]T [°C]water Vacuum Ethylene glycol02468101220 40 60 80keff [W/m K]T [°C]Parallel SeriesLower Maxwell Upper MaxwellAlexander ExperimentComparison of the experimental values of the effective thermal conductivity of the water-saturated porous sampleThe effective thermal conductivity of the sample for different saturated fluidsEffective thermal conductivityDroplet test A water droplet (4.5 μL) is deposited into the wick structure.The droplet infiltrates the porous layer in <0.02 s confirming excellent wetting.Instantaneous state photos of a deionized water droplet released onto the porous sampleHighlightsFabrication & Morphology analysis Development of experimental devices and resultsConclusionsThe porous sample is manufactured using a ConceptLaser Mlab Cusing 90, 3D metal printing machine.The porous structure of 1 x 20 x 40 mm3 ismanufactured with a 500 µm octahedral unit cell size.SS 316L powder size is in the range of 15-20 µm andpore sizes in the fabricated sample are around 160µm.The porosity of the sample, measured by theArchimedes method, is 0.461.The experimental set up includes a heating and coolingsections and the test chamber.Using the Fourier model the porous media effective thermalconductivity is calculated.

Enhancing thermal management applications through porous structures fabricated by selective laser melting

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