Additive Manufacturing for Advanced Cooling Technologies

Transcription

1 Additive Manufacturing for Advanced Cooling Technologies D.L. Youchison Fusion & Materials for Nuclear Systems R.A. Lowden Materials Science & Technology with input from: R.E. Nygren Sandia National Laboratories D.E. Wolfe Applied Research Laboratory, CIMP-3D FESAC TEC Workshop June 20-22, 2017 ORNL is managed by UT-Battelle for the US Department of Energy

2 Cooling channels and joining create complexity Helium divertor Present: intensive use of machining (edm), joining and high part numbers = low reliability, high cost normal flow heat exchanger Exit plenum Helium exit channel Alumina insulation Inlet plenum DOE PM circa 1994: No swiss watches! Transverse support beams 122 mm Microchannels Glidcop AL-15 fins Additive Manufacturing (AM) technology changes the game 2 FESAC - Youchison Blanket module Applied heat flux Helium exit groove Glidcop AL-15 face plate

3 Selective Laser Melting (SLM) ~ Laser Engineered Net Shape (LENS) Additive Manufacturing Materials Development Laboratory at ORNL for Accelerator Production of Mo-99 3 FESAC - Youchison ORNL: Building 4508, Room 224

4 Selective Laser Melting Process Variables Primary Selective Laser Melting (SLM) Process Variables - Point Distance (μm) - Exposure Time (μs) - Power (W) - Hatch Distance (μm) - Layer Thickness (μm) - Powder Particle Size (μm) Melt Pool is Dependent Upon Exposure Time and Power Laser Spot = 130 μm 4 FESAC - Youchison

5 Scan or Build Strategy Influences Critical Features Such as Porosity, Microstructure, and Surface Roughness 5 FESAC - Youchison

6 Unique Processing Capability Was Established to Examine SLM AM of Molybdenum 6 FESAC - Youchison Renishaw AM watt selective laser melting system Spot size = 130 mm Reduced build volume insert for small-scale experiments 75 x 75 x 60 mm If needed, system can be returned to standard build volume (250 x 250 x 285 mm)

7 A Dedicated Automated Serial Sectioning and Imaging System is Included in the Lab 5 x 2 x 1 mm slices UES RoboMet.3D 7 FESAC - Youchison

8 We Too Enjoy a Bit of Sham Wow ~ 25 mm AM Moly TRL3 TRL4 8 FESAC - Youchison

9 SLM Summary Targets and components can be produced employing traditional press and sinter powder metallurgy and additive manufacturing approaches Complete metal powder processing capabilities including reduction, blending, milling, sieving (including inert atmosphere), spray drying and plasma spheroidization are available A full-service AM lab has been established to support refractory metal isotope target and assembly fabrication SLM AM system with reduced build volume Spray drying Plasma spheroidization Powder characterization Automated metallography with 3D image reconstruction Glove box Reactive or environmentally-sensitive powders can be accommodated. Mo > W > carbides like HfC and SiC 9 FESAC - Youchison

10 Advanced manufacturing is needed for fusion Plasma Facing Components (PFCs) FES-PSI workshop white papers highlighted AM. Very flexible AM process builds parts layer by layer using lasers or other techniques that fuse powders or fibers. AM can produce complex spatial features such a micro-cooling channels and materials architecture such as nano-particles, porosity and composition gradients. ARL s CIMP-3D provides world-class capabilities to benefit a broad range of government and industry sponsors The new AM Demonstration Facility has three AM systems, a state-of-the-art design studio and a prototyping lab 10 FESAC - Youchison

11 Advanced manufacturing is needed for fusion PFCs FES-PSI workshop white papers highlighted the need for PFCs with integrated structures and complex spatial features such a micro-cooling channels and materials architecture such as nano-particles, porosity and composition gradients. Field assisted sintering technology (FAST), sometimes called spark sintering, fuses powders under pressure while current passing through the powder creates arcing at contact points. Using an industrial scale press for field-assisted scintering (FAST), ARL can make complex shapes, such as DIII-D or NSTX tiles or probe heads PFCs with composition gradients, controlled porosity, micro-channels for cooling and joints with dissimilar materials 11 FESAC - Youchison

12 Spark Plasma Sintering TRL4 12 FESAC - Youchison

13 Can AM enable development of better helium jets? q 10 MPa He m-dot=10 g/s Tin=600 C q =10 MW/m 2 HEMJ from FZK Large jets Too many joints 13 FESAC - Youchison

14 Velocity distribution with 10 g/s input 1 mm central jet HEMJ He-cooled Thimble 500 mm jet 291 m/s Jets thin the thermal boundary layer that insulates the wall from the convective fluid. 14 FESAC - Youchison 14

15 Temperatures & stresses inside the cap are high. Joint failures are inherent issue. 15 FESAC - Youchison

16 18 microjet array w/ nozzles q 200 mm jets W faceplate Outlet plenum } 200 mm standoff electronics application W jetbody Al Inlet plenum 16 FESAC - Youchison

17 Temperature distribution under faceplate collimated vectors at impingement. Extensions provide an exhaust plenum isolated from the jets. 17 FESAC - Youchison

18 Very Uniform Velocity Distribution Exists at Boundary Layer 200 m/s v she = C 18 FESAC - Youchison 366 m/s

19 Microjet arrays could be fabricated in tungsten using AM with integral manifolds. Is it possible? TRL1 19 FESAC - Youchison

20 SPECT collimators from AM tungsten 450 microns Yes, Likely. Rapid additive manufacturing of MR compatible multipinhole collimators with selective laser melting of tungsten powder Karel Deprez,a) Stefaan Vandenberghe, and Karen Van Audenhaege, Jonas Van Vaerenbergh, Roel Van Holen - Belgium Medical Physics 40, (2013); doi: / TRL3 Successful demonstration of dimensions not very far from the microjet feature sizes we require! 20 FESAC - Youchison

21 Chemical vapor deposition and infiltration of foam media is advanced manufacturing. Metallic foams led to advanced recuperators/regenerators 8 mm x 8 mm x 8 mm 45 ppi RVC skeleton Tomography VGStudio MAX by Volume Graphics File translation 3dShop by C4W Rhino 3d Cubit Star CCM+ extract a volume 21 FESAC - Youchison

22 Analysis Reveals Turbulent Mixing and Fin Effect Created by Foam CVI close-outs demonstrated 627 C TRL3 27 C He Convection models for 2 mm x 2 mm 65 ppi, 10% dense moly foam attached to 1 mm thick moly walls. Temperature distribution is shown on left with velocity vectors and streamlines through the foam on the right. CVI close-out Exposed hollow ligament channels 22 FESAC - Youchison

23 Foams can provide compliance, minimize stress Exploiting Ultramet foams for fusion power conversion! He-He regenerator Li-He HX 23 FESAC - Youchison 2009 TRL5 2011

24 What about low-z heat sink? newest innovation from ORNL: Created a light-weight, low-z heat sink with the isotropic thermal conductivity of copper, no melting point First time ever: heat sink can be a plasma facing material directly or support a refractory metal coating! (disruptive game changer) Better heat transfer lower surface temperatures Less mass and longer erosion lifetimes Reduced thermal stress in joint due to reduced temperature gradient Demonstrated fabrication Allcomp densified foam >350 W/mK, ~1.5 g/cc kth=265 W/mK C p =1020 J/kgK density=1.1 g/cm 3 24 FESAC - Youchison

25 Uses an Engineered Graphitic Structure Developed by James Klett at ORNL Foam microstructure Morphology consists of high conductivity graphitic basal layers oriented along the foam ligaments, but the ligament directions are random 25 FESAC - Youchison

26 Conductivity in CFC vs Isotropic Foam The heatsink is an important part of the cooling system. It can spread or concentrate the heat flow. FOAM 26 FESAC - Youchison

27 Isotropic Foam Temperature Distribution q =10 MW/m 2 h=20,000 W/m 2 K k=245 W/mK Near future: PSI-II exposure W7-X exposure 30 mm GLADIS mockup 10-mm-ID CuCrZr tube K=334 W/mK 27 FESAC - Youchison TRL3

28 High-Z coatings CVD/PVD coatings are a form of advanced manufacturing 28 FESAC - Youchison

29 29 FESAC - Youchison AM used for sensor development

30 Risks and Conclusions AM allows for near net shape fabrication of refractory metals for PFCs and blankets Carbides may be possible, but not demonstrated yet? Small (~0.1 mm) optimized features are possible Scale-up to large area devices is possible AM provides dramatic reductions in fabrication costs Elimination of joints via graded interfaces Reduction in part counts and intricate assemblies Useful for heatsinks, armor, blankets and power conversion Must increase densities and k th. Powder handling and purity remain issues. Helium requires a high pressure safety boundary & robust seals Need dedicated test facilities for prototypical testing (NOTHING is >TRL5 without it!) 30 FESAC - Youchison