1 / 19

Ultra-light carbon fiber structures: evaporative tests

Ultra-light carbon fiber structures: evaporative tests. Claudio BORTOLIN (CERN) Martin DOUBEK ( CTU, Czech Technical University, Prague ) Andrea FRANCESCON ( CERN ) Manuel GOMEZ MARZOA (CERN) Romualdo SANTORO (CERN) 4 th September 2012. Contents. Heater analysis

kitra-wells
Download Presentation

Ultra-light carbon fiber structures: evaporative tests

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ultra-light carbon fiber structures: evaporative tests Claudio BORTOLIN (CERN) Martin DOUBEK (CTU, Czech Technical University, Prague) Andrea FRANCESCON (CERN) Manuel GOMEZ MARZOA (CERN) RomualdoSANTORO (CERN) 4th September 2012 ALICE Cooling Meeting - 4th September 2012

  2. Contents • Heater analysis • NTCs vs. thermographic picture analysis • Single-phase water tests: D08 prototype • Evaporative tests: D08 prototype • Comparison with water single-phase tests • Temperature distribution • Conclusion • Prototype and test facility optimization ALICE Cooling Meeting - 4th September 2012

  3. Heater power distribution analysis • The D06 prototype with single-phase water tests: presented at WG4 Meeting the 27th July 2012 • Two warmer regions were seen towards the centre of the stave at the sides. • Possible causes: • Lack of thermal contact plate-heater • Manufacturing difficulties • Gluing defects • Heater power dissipation maldistribution? 8 L min-1, 0.5 W cm-2 • A single heater and the D04 prototype heater will be powered up: • Check temperature distribution • Deviation of measurements thermocamera/NTCs ALICE Cooling Meeting - 4th September 2012

  4. Heater power distribution analysis 3 1 2 3 1 2 3 2 1 • *ΔT-n = Average_T_NTC – Average_T_ThermoPic ALICE Cooling Meeting - 4th September 2012

  5. Heater power distribution analysis 3 2 1 3 1 2 3 2 1 • *ΔT-n = Average_T_NTC – Average_T_ThermoPic ALICE Cooling Meeting - 4th September 2012

  6. D08 prototype: description IN OUT ALICE Cooling Meeting - 4th September 2012

  7. D08 prototype: water tests ALICE Cooling Meeting - 4th September 2012

  8. D08 prototype: water tests • Temperature along stave: D08, 8 L min-1, 0.3 W cm-2 • Assuming same power density across stave, D08 performs better than D04 • Cannot cool at 0.5 W cm-2 and needs optimization ALICE Cooling Meeting - 4th September 2012

  9. Water tests: conclusion ALICE Cooling Meeting - 4th September 2012

  10. D08 2-phase C4F10 tests @DSF • Inlet vapor quality: • Superheating at stave outlet: T = const x = const • Mass flow rate calculation: 1 p [bar] where L is latent heat [kJ kg-1]: 3 3’ 2 4 Qstave[W] • Usually: h [kJ kg-1] ALICE Cooling Meeting - 4th September 2012

  11. D08: water vs. C4F10 @0.3 W cm-2 Evaporative cooling system performs as good as single-phase water ALICE Cooling Meeting - 4th September 2012

  12. D08: water vs. C4F10 @0.5 W cm-2 • Good selection of mass flow rates and agreement between thermographic pictures and NTCs over the heater. • Knowing the vapor quality at the outlet is very important. ALICE Cooling Meeting - 4th September 2012

  13. D08: C4F10 tests discussion • Two cases did not perform as expected: • Low vapor quality at the stave entrance: saturated liquid entering stave? • Low vapor quality at stave outlet: single phase flow? • Low vapor quality at the stave entrance: saturated liquid entering stave? • Mass flow rate too low: superheated vapor at stave outlet ALICE Cooling Meeting - 4th September 2012

  14. Conclusion • Almost the same cooling performance is achieved with single-phase water cooling circuit as when using evaporative C4F10 for the same prototype. • There is not a big increase of the HTC wall-fluid using evaporative C4F10 • ΔT wall-water: through the HTC, establishes the margin of improvement by using a better cooling system for this setup: • C4F10, two-phase: • Water, single phase: Evaporative C4F10 means CFD Simulations ALICE Cooling Meeting - 4th September 2012

  15. Optimization lines • Stave optimization: • Pipe inner diameter: can be smaller than 1.5 mm (but less contact area!) • More rigid piping: PEEK (avoid deformations, pinching, ensure contact) • D08 prototype shows no better thermal performance with evaporative flow • Improve weak parts of model (thermal contact, gluing…) • Structure thermal analysis/simulation helpful • Avoid connectors: leaks, extra pressure drop. • Proposal: single pipe w/ 180 deg elbow. • In/Out connector: select useful pipe diameter. • Setup optimization: • A by-pass will be added to the circuit in DSF in order to be able to work with smaller mass flow rates (especially microchannel) • For this reason, a coriolisflow meter will be moved in DSF • Need for subcooled liquid before the flow meter! • Sensors calibration (see backup slide). ALICE Cooling Meeting - 4th September 2012

  16. Ultra-light carbon fiber structures: evaporative tests Claudio BORTOLIN (CERN) Martin DOUBEK (CTU, Czech Technical University, Prague) Andrea FRANCESCON (CERN) Manuel GOMEZ MARZOA (CERN) RomualdoSANTORO (CERN) 4th September 2012 ALICE Cooling Meeting - 4th September 2012

  17. Backup D08: C4F10 tests discussion • Where; • Subcooling = TSAT@p1 – T1 (entrance of stave). • T3’: saturation temperature at p=p3. Used to calculate superheating at the stave outlet (if superheated vapor present). • Error in temperature measurement at point 3: calculated as ε = T3-T3’ ALICE Cooling Meeting - 4th September 2012

  18. Backup An estimation of the uncertainty of measurements: • At point 3, calculate h for saturated liquid and vapor using p3. With p3 and T3, the point is superheated vapor and h3 can be calculated. If temperature measurement was fine, , and: • In the real case, x3 > 1. The deviation is the % of total error resulting frpm measuring p, T and calculating the enthalpies (RefProp). ALICE Cooling Meeting - 4th September 2012

  19. Backup An estimation of the uncertainty of measurements: • At point 3, vapor quality at the stave outlet (calculated using an energy balance) indicates that the fluid is in the the two-phase region. If that is the case, then: • However, a is read instead. The difference remains stable for most of the cases: • Calibration systematic error? • Incorrect setting of temperature sensors? ALICE Cooling Meeting - 4th September 2012

More Related