HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT Ronald D. Boyd Sr., PhD, PE, PI Distinguished Professor, Honeywell Professor, Director of the Thermal Science Research Center (TSRC), and TAMUS Regents Professor Roy G. Perry College of Engineering Mail Stop 2525 P.O. Box 519 Prairie View A&M University Prairie View, TX Ph: or Fax: or Annual Plasma-Facing Component Workshop Massachusetts Institute of Technology (MIT) Cambridge, MA July 8-10, 2009

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT OUTLINE  BACKGROUND  Peaking Factor (Base-Line)  ITER PFC Monoblock  Recent Literature  Passive Enhancement  SIMULATION METHODOLOGY  SIMULATION METHODOLOGY RESULTS  SELECTED EXPERIMENTAL PF DATA  ONGOING WORK  ACKNOWLEGMENTS

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT BACKGROUND

φ h(φ) φ = 0 Deg. riri TbTb Swirl Single-Phase Convection or Two- Phase Water Flow Boiling (One Possibility For ITER) H w Swirl Tape r φ = 0 Deg. φ h(φ) t Solid (k) One Possibility (Base-Line Model) for PFC Monoblock High Heat Flux Removal (HHFR) for ITER. Another Possibility Uses a Hypervapotron Rather Than the Circular Flow Channel with a Twisted Tape. For DEMO, High Velocity Helium Gas and/or a Liquid Metal (e.g., Jet Impingement) Will be Coolant Candidates Rather Than Water.

PFC ITER Monoblock (M. Merola, Private Communication)

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT BACKGROUND (continued)

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT BACKGROUND (continued) To this Presenter’s Knowledge, the PF Correlation by Boscary, Febre, and Schlosser (Int. J.H.M. Trans., 42, 1999) Appears to be the Only One in the Technical Literature. However, the Correlation was Applied Only to Glidcop A1-25 and Had No Thermophysical or Thermal-Hydraulic Parameter Dependence for < Critical Heat Flux (CHF) but Was Dependent on: (1) w/r i (2.66 < w/r i < 3.4), and (2) t/r i (0.16 < t/r i < 0.6).

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT BACKGROUND (continued)  Federici and Raffray (J. Nucl. Mats., 244, 1997) Evaluated PF in Copper Monoblocks With and Without 316 Stainless Steel Inserts.  Later, Raffray et al. (Fusion Engineering and Design, 45, 1999) Noted a Future Need to Better Assess PFs. PFs were Presented as Functions of t & w for a CFC Monoblock with a CuCrZr Tube Insert.

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT BACKGROUND (continued) PASSIVE HIGH HEAT FLUX ENHANCEMENT  In the 2008 Int. HHFC Workshop at UCSD, Escourbiac Noted That Enhancement is Possible When Defects are Located at  = 0 degrees.  In 1994, Boyd (Fusion Technology, 25) Noted Enhancement is Possible for the Following Design Configurations:

Modified Channel Design for Improved Accommodation of HHF for the Single-Side Heated Configuration (q o = q oo and  oo =  /2).. HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT

φ oo HHFR Fluid or Coolant Plane of Symmetry Insulation Solid φ = 0 Deg. φ r riri roro h(φ) TbTb Simulation for Base-Line PFC Monoblock. HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT PF SIMULATION METHODOLOGY

φ h(φ ) φ = 0 Deg. riri TbTb H w Swirl Tape r φ = 0 Deg. φ h(φ) t Solid (k) Plane of Symmetry  Greater Than 98% Accurate for Predicting PF and Peak Inside Flow Channel Temperature.  Simulation Model Appears to be Applicable to Different  Monoblock Geometries,  Monoblock Materials,  Coolants, and  Coolant Flow Regimes.  PF = f(t, w, H, r i, Bi), Note: Another Possibility for HHFR is the Hypervapotron, and it will be Added to this Work.

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT SELECTED EXPERIMENTAL PF DATA

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT RefGP outΔtsubH1HWMaterials krefr i ΦiΦcPF #(Mg/m 2 s) (Mpa) out (mm) (W/mK) (mm)(MW/m 2 ) Peaking Mass VelExit( °C ) ICHFMaxFactor or VP CHF {m/s} at Wall Fluid Vel 1(15) Cu- Al2O (10) Cu- Al2O (15) Cu- Al2O (10) Cu- Al2O (15) Cu- Al2O (11) Cu- Al2O (16) Cu- Al2O (16) Cu- Al2O (14) Cu- Al2O (16) Cu- Al2O (15) Cu- Al2O (14) Cu- Al2O (10) Cu- Al2O (5) Cu- Al2O Boscary.J, Fabre. J, Schlosser J., “Critical Heat Flux of Water Subccoled Flow in One Side Heated Swirl Tubes” (Int. J.H.M. Trans., 42, 1999).

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT CONCLUSIONS  A Conjugate Heat Transfer, High Heat Flux Simulation Methodology has Been Developed Which Accurately Predicts the Flow Channel: (1) Radial Heat Flux PF to Within Less Than 2% Inaccuracy, and (2) to Within Less Than 1%.  Work is Proceeding to Extend This Simulation to PF and Correlations Which Include the Basic Monoblock Geometry, Fluid, and Thermal-Physical Parameters.

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT ONGOING WORK  Simulation PF Correlation Development  Related Data Search  Model Validation/Verification

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT Inside Surface Heat Flux Map For An Externally Applied Single-Side Heat Flux, Where q = q o = constant and  oo =  /2.

HIGH HEAT FLUX PEAKING FACTORS AND ENHANCEMENT ACKNOWLEDGMENTS THE THERMAL SCIENCE RESEARCH CENTER (TSRC) IN THE COLLEGE OF ENGINEERING AT PRAIRIE VIEW A&M UNIVERSITY IS APPRECIATIVE TO THE OFFICE OF FUSION ENERGY SCIENCES PROGRAM (U.S. DEPARTMENT OF ENERGY, DOE) FOR ITS SUPPORT OF THIS WORK UNDER CONTRACT #DEFG02-97ER FINALLY, THE AUTHOR IS APPRECIATIVE TO MR. AARON M. MAY, MR. FRANCOIS MARTIN, AND MS. VIVIAN GLOVER FOR THEIR STEADFAST SUPPORT.