Additive Design and Manufacturing of a Composite Polymer Heat Exchanger

Transcription

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2 Additive Design and Manufacturing of a Composite Polymer Heat Exchanger Jake Boxleitner

3 Project Overview ARPA-e ARID Program Power plant cooling HVAC applications kw/kg and $/kw Page 3

4 Project Overview Common additive processes Filament Resin Powder Fused Filament Fabrication (FFF) Continuous Liquid Interface Production (CLIP) Stereolithography (SLA) Selective Laser Melting (SLM) Binder jetting Page 4

5 Project Overview Performance Weighted Cost ($/kw) reduced $/kg Phase 1 result - pin fin Phase 1 result - airfoils Phase 2 - subfins conventional heat exchangers Phase 2 - tapered fins Mass-weighted Performance (kw/kg) constant $/kg Page 5

6 HX Design and Modeling Heat Exchanger Topology 6 by 6 frontal area Air Lytron 6110 Water Microstructure Macrostructure Page 6

7 HX Design and Modeling Heat flow and resistance network T water R conv Water channel qሶ Air channel Fins Walls R wall R unfinned R finned T air Page 7

8 HX Design Thermal model Conduction resistance Neat polymer conductivity: W/m-K Wall thickness Convection resistance Heat transfer coefficient Feature size Pressure drop T water R conv R wall 5.5 mm R unfinned R finned 1.2 mm T air Page 8

9 Manufacturing University of Wisconsin Polymer Engineering Center FFF printers Makergear M2 Aon3D M Cosine AM1 Page 9

10 Manufacturing Nomenclature and build orientation Filament Nozzle Print direction (x, y) Nozzle diameter Layer height Z Y X Build Direction (z) Page 10

11 Manufacturing Geometry printing process Microstructure channel Microstructure kazoo Page 11

12 Manufacturing Test Channel Slicing Build Direction (z) Page 12

13 Manufacturing Test Channel Slicing Build Direction (z) Layer A cut plane Layer A Layer A tool path Page 13

14 Manufacturing Test Channel Slicing Build Direction (z) Layer A cut plane Layer A Layer A tool path Page 14

15 3 Manufacturing Tool path comparison Uncontrolled tool path Optimized tool path Page 15

16 3 Manufacturing uct geometry analysis 5.5 mm 1.2 mm Page 16

17 3 Manufacturing uct geometry analysis 0.2 mm 0.4 mm Ø0.4 mm Page 17

18 3 Manufacturing Evolution of the kazoo Page 18

19 3 Manufacturing Kazoo failure modes fin-to-wall connection wall Page 19

20 3 Pressure Testing Pressure Testing Page 20

21 3 Pressure Testing Shot on iphone 6 Addition equipment and software not used Page 21

22 3 Pressure Testing Page 22

23 3 Pressure Testing Design of Experiments Setup Layer Height Print Speed Extrusion Ratio Extrusion Temperature Filament Temperature Nozzle Print speed Extrusion Ratio Layer height Nozzle diam. Layer height Page 23

24 3 Pressure Testing Design of Experiments Results Page 24

25 3 Pressure Testing Kazoo formic acid treatment Page 25

26 Manufacturing As-printed airfoil heat exchanger Page 26

27 4 Model Validation Test loop schematic HX Water DP RTD Hydrostatic Pump Pump Nozzle DP RTD RTD Flow Meter HX Frontal Area: 70 mm x 70 mm HX HX Air DP RTD Hot Water Bath Pressure Gauge Page 27

28 Model Validation ASHRAE Standard 33 almost Page 28

29 Model Validation Test results and model prediction Page 29

30 Thermal model Material conductivity and minimum wall thickness trade study Page 30

31 Overview of Project Performance Weighted Cost ($/kw) reduced $/kg Phase 1 result - pin fin Phase 1 result - airfoils conventional heat exchangers Mass-weighted Performance (kw/kg) constant $/kg Page 31

32 Material Development Carbon fiber Copper spheres Copper fibers Aluminum flake Graphite flakes Page 32

33 Material Development Recall heat flow and resistance network Water channel k3 k2 k1 Air channel k2 k1 Fins Walls k1 Fiber alignment Flake alignment Oriented carbon fibers Page 33

34 3 Material Development Nozzle clogging with filled polymers Flow-ability Fibers Spheres Page 34

35 3 Material Development Material performance comparison Page 35

36 Project Overview Performance Weighted Cost ($/kw) reduced $/kg Phase 1 result - pin fin Phase 1 result - airfoils conventional heat exchangers Phase 2 - tapered fins Mass-weighted Performance (kw/kg) constant $/kg Page 36

37 4 Geometry Development CFD unit cell definition and boundary conditions u, T a,in T w Page 37

38 4 Geometry Development CFD geometry correlations and thermal model friction factor from correlation Nusselt from correlation Nusselt from CFD +20% +20% -20% -20% Standard linear regression Nonlinear regression Standard linear regression Nonlinear regression Nu, f T water R conv R wall R unfinned R finned friction factor from CFD Felber, R., Design, simulation, and testing of novel air-cooled heat exchangers manufactured by fused filament fabrication, M.S. thesis, Dept. of Mech. Eng., Univ. of Wisc., Madison, WI, T air Page 38

39 Geometry Development Tapered pin fins and heat flow comparison Water Flow Air Flow Tapered pin Straight pin Page 39

40 Manufacturing Tapered pin fin build orientation Page 40

41 Manufacturing Tapered pin fin tool path Layer A Layer B Layer C Page 41

42 Manufacturing Tapered pin fin tool path Layer A Layer B Layer C Layer A Layer B Layer C Page 42

43 Manufacturing Tool Pathing Geometry Comparison Airfoils Tapered Fins Page 43

44 Manufacturing Tool Pathing tapered pin fin Page 44

45 Geometry Development Thermal Advantages Page 45

46 Geometry Development Water Side Behavior Page 46

47 Geometry Development Water Side Behavior Water side thermal gradients Page 47

48 Geometry Development Hollow-through tapered pin fins Page 48

49 Geometry Development Revisit iterative printing process Page 49

50 Geometry Development Page 50

51 Geometry Improvements Tapered pin fin test results and thermal model comparison to airfoil results Page 51

52 Project Overview Performance Weighted Cost ($/kw) reduced $/kg Phase 1 result - pin fin Phase 1 result - airfoils conventional heat exchangers Phase 2 - tapered fins Mass-weighted Performance (kw/kg) constant $/kg Page 52

53 Future Work Geometry development Material development Tool Pathing Streamlined, tapered, and decoupled fins Filled and flow-able materials Page 53

54 Thank you for your attention Polycarbonate Aluminum Flake Tapered Pin Fin Heat Exchanger Page 54

55 Appendix Page 55

56 Other Additive Processes - SLM A Page 56

57 Other Additive Processes - CLIP A Page 57

58 Tool Paths A Page 58

59 Water-side CFD Modeling Flow misdistribution: 4.3% deviation from average flow rate per channel A Section A-A A Page 59

60 3 Manufacturing Printer hardware issues Milestone due: 11/30/17 Feed gear abrasion This leads to a reduction in the effective diameter of the gear, leading to under-extrusion. These grooves represent ~2% reduction in the extrusion ratio. 2 weeks of printing The Makergear was adjusted to use these hardened steel gears Page 60

61 3 Manufacturing Printer hardware issues Nozzle abrasion: the actual extruded bead becomes wider and shorter than the nominal bead due to abrasion by the filler. Nominal 0.35 mm nozzle grew to 0.7 at the exit! This leads to leaks between the layers due to an incomplete fill in the z-direction. A hardened steel nozzle shows no wear after several weeks. Nominal Bead Actual Bead Page 61