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) 4th September 2012 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

ALICE Cooling Meeting - 4th September 2012 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 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

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 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

Heater power distribution analysis I [A] V [V] P [W] Case: Single heater ΔT-3* [°C] ΔT-2* [°C] ΔT-1* [°C] 0.15 4.2 0.63 -0.1 -0.7 -0.5 0.25 7.4 1.85 -1.6 -2.7 0.35 11.2 3.92 -7.0 1.3 3 2 1 3 2 1 3 2 1 *ΔT-n = Average_T_NTC – Average_T_ThermoPic M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

Heater power distribution analysis I [A] V [V] P [W] Case: D04 heater ΔT-3* [°C] ΔT-2* [°C] ΔT-1* [°C] 0.15 4.4 0.66 -2.0 -0.4 -0.5 0.25 7.4 1.85 -1.8 -0.7 0.35 10.6 3.71 -1.6 -1.0 -0.8 3 2 1 3 2 1 3 2 1 *ΔT-n = Average_T_NTC – Average_T_ThermoPic M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

D08 prototype: description Pipe OD [mm] 1.5 Pipe thickness [mm] 0.035 Pipe ID [mm] 1.43 Carbon paper sleeve thickness tcs [mm] 0.03 CF tangential coverage β [deg] ~ 360 Pitch p+w [mm] 7.5 Fiber width w [mm] p [mm] 6 Angle fibers with pipe axis α [deg] 23 IN OUT M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

D08 prototype: water tests Case: D08, 0.3 W cm-2 Q [L h-1] Δp [bar] v [m s-1] TH20 [°C] ΔTH20 [°C] ΔTHeater [°C] 3.0 0.19 0.52 15.1 2.4 9.8 5.0 0.25 0.86 14.8 1.5 9.0 8.0 0.46 1.38 14.7 0.7 12.0 0.74 2.08 0.6 6.8 Case: D04, 0.31 W cm-2 0.13 2.9 12.2 4.9 0.22 0.85 1.9 8.1 0.38 1.40 14.6 1.2 10.8 12.3 0.76 2.13 14.5 0.8 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

D08 prototype: water tests Case: D08, 0.5 W cm-2 Q [L h-1] Δp [bar] v [m s-1] TH20 [°C] ΔTH20 [°C] ΔTHeater [°C] 8.0 0.43 1.38 14.7 1.5 16.0 12.0 0.76 2.08 14.8 0.6 13.5 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 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

Water tests: conclusion M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

ALICE Cooling Meeting - 4th September 2012 D08 2-phase C4F10 tests @DSF Inlet vapor quality: 𝑥= 𝑚 𝑉𝑎𝑝𝑜𝑟 𝑚 𝐿𝑖𝑞 = ℎ 2 − ℎ 𝐿𝑖𝑞 𝑆𝑎𝑡 ​ 𝑝 2 ℎ 𝑉𝑎𝑝 𝑆𝑎𝑡 ​ 𝑝 2 − ℎ 𝐿𝑖𝑞 𝑆𝑎𝑡 ​ 𝑝 2 Superheating at stave outlet: Δ 𝑇 𝑆𝑢𝑝𝑒𝑟ℎ𝑒𝑎𝑡𝑖𝑛𝑔 = 𝑇 4 − 𝑇 3 ′ T = const x = const Mass flow rate calculation: 𝑚 = 𝑄 𝐿 Δ 𝑥 2−3 1 𝑄 = 𝑚 𝐿 Δ 𝑥 2−3 ; p [bar] where L is latent heat [kJ kg-1]: 3 𝐿= ℎ 𝑉𝑎𝑝 𝑆𝑎𝑡 − ℎ 𝐿𝑖𝑞 𝑆𝑎𝑡 3’ 2 4 Usually: Qstave [W] Δ 𝑥 𝐸𝑣𝑎𝑝 <0.5 0.2< 𝑥 𝐸𝑣𝑎𝑝 𝐼𝑛 <0.3 h [kJ kg-1] 0.8< 𝑥 𝐷𝑟𝑦𝑜𝑢𝑡 <0.9 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

D08: water vs. C4F10 @0.3 W cm-2 Water C4F10 Q [L h-1] ΔpSt [bar] v [m s-1] TH20 [°C] ΔTH20 [°C] ΔTHeater [°C] 3.0 0.19 0.52 15.1 2.4 9.8 5.0 0.25 0.86 14.8 1.5 9.0 8.0 0.46 1.38 14.7 0.7 12.0 0.74 2.08 0.6 6.8 C4F10 m [g s-1] xIn xOut TC4F10-Out [°C] 0.16 0.06 0.08 0.92 16.8 0.20 0.07 0.75 14.0 5.5 0.40 0.42 13.4 5.6 0.60 0.2 0.31 6.0 Evaporative cooling system performs as good as single-phase water M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

ALICE Cooling Meeting - 4th September 2012 D08: water vs. C4F10 @0.5 W cm-2 Water Q [L h-1] ΔpSt [bar] v [m s-1] TH20 [°C] ΔTH20 [°C] ΔTHeater [°C] 8.0 0.43 1.38 14.7 1.5 16.0 12.0 0.76 2.08 14.8 0.6 13.5 C4F10 m [g s-1] xIn xOut ΔTSH [°C] 0.4 0.17 0.06 0.65 13.4 13.0 0.26 0.05 0.46 14.0 0.8 0.33 0.03 0.36 14.5 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. M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

ALICE Cooling Meeting - 4th September 2012 D08: C4F10 tests discussion Two cases did not perform as expected: Case: 0.3 W cm-2 m [g s-1] ΔpSt [bar] xIn [m s-1] xOut TC4F10-Out [°C] ΔTHeater [°C] 0.8 0.28 0.04 0.26 13.3 14.0 Low vapor quality at the stave entrance: saturated liquid entering stave? Low vapor quality at stave outlet: single phase flow? Case: 0.5 W cm-2 m [g s-1] ΔpSt [bar] xIn [m s-1] xOut TC4F10-Out [°C] ΔTHeater [°C] 0.2 0.09 0.08 1.20 21 28.0 Low vapor quality at the stave entrance: saturated liquid entering stave? Mass flow rate too low: superheated vapor at stave outlet M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

HTC wall-fluid [W m-2 K-1] 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: Q [l/h] V [m s-1 ] Re [-] HTC [W m-1 K-1] 3.00 0.52 653 1650 12.00 2.08 2612 8076 Evaporative C4F10 means HTC wall-fluid [W m-2 K-1] Tmax Silicon [oC] 1646 43.02 5000 39.25 10000 38.22 CFD Simulations M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

ALICE Cooling Meeting - 4th September 2012 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 coriolis flow meter will be moved in DSF Need for subcooled liquid before the flow meter! Sensors calibration (see backup slide). M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

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) 4th September 2012 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

ALICE Cooling Meeting - 4th September 2012 Backup D08: C4F10 tests discussion Q [g s-1] Pd Heater [W cm-2] T1 [oC] P1 [bar] Subcool_1 p2 [bar] ∆pLam [bar] Tsat-p2 [°C] xin-stave [-] T3 [oC] p3 [bar] ∆pSt [bar] T3' [°C] Error@3 [°C] Superheating_3 [°C] hOut [kJ kg-1] xout-stave [-] 0.16 0.30 20.2 3.07 9.1 1.80 1.27 13.2 0.08 16.8 1.74 0.06 12.2  - - 99.37 0.92 0.2 20.4 3.10 9.2 1.82 1.28 13.5 14.0 1.75 0.07 12.4 1.6 84.40 0.75 0.50 1.84 1.26 13.8 21.0 0.09 8.6 125.74 1.20 0.4 20.3 3.08 1.81 13.3 13.4 1.0 53.94 0.42 3.06 8.8 1.93 1.13 15.1 1.76 0.17 12.5 0.9 74.71 0.65 0.6 2.87 6.8 1.96 0.91 15.6 43.81 0.31 2.85 6.6 2.02 0.83 16.5 0.05 0.26 0.8 57.59 0.46 2.79 5.9 2.03 0.76 16.6 0.04 0.28 38.75 2.78 5.8 2.11 0.67 17.7 0.03 1.78 0.33 12.8 0.5 49.08 0.36 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’ M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

An estimation of the uncertainty of measurements: Backup An estimation of the uncertainty of measurements: Q [g s-1] Pd Heater [W cm-2] T1 [oC] P1 [bar] Subcool_1 p2 [bar] Tsat-p2 [°C] T3 [oC] p3 [bar] ∆pSt [bar] h3 [kJ kg-1] h3Lsat xSat-p3 [-] T3' [°C] Error@3 [°C] hOut xout-stave [-] 0.16 0.30 20.2 3.07 9.1 1.80 13.2 16.8 1.74 0.06 111 14.92 107 1.04 12.2  - 99.37 0.92 0.2 20.4 3.10 9.2 1.82 13.5 14.0 1.75 0.07 108 15.09 1.01 12.4 1.6 84.40 0.75 0.50 1.84 13.8 21.0 0.09 114 1.08 125.74 1.20 0.4 20.3 3.08 1.81 13.3 13.4 1.0 53.94 0.42 3.06 8.8 1.93 15.1 1.76 0.17 15.26 12.5 0.9 74.71 0.65 0.6 2.87 6.8 1.96 15.6 43.81 0.31 2.85 6.6 2.02 16.5 0.26 0.8 57.59 0.46 2.79 5.9 2.03 16.6 0.28 38.75 2.78 5.8 2.11 17.7 1.78 0.33 15.60 1.00 12.8 0.5 49.08 0.36 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). ℎ 𝑉𝑎𝑝 𝑆𝑎𝑡 ​ 𝑝3 = ℎ 3 𝑥= 𝑚 𝑉𝑎𝑝𝑜𝑟 𝑚 𝐿𝑖𝑞 = ℎ 3 − ℎ 𝐿𝑖𝑞 𝑆𝑎𝑡 ​ 𝑝 3 ℎ 𝑉𝑎𝑝 𝑆𝑎𝑡 ​ 𝑝 3 − ℎ 𝐿𝑖𝑞 𝑆𝑎𝑡 ​ 𝑝 3 =1 M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012

An estimation of the uncertainty of measurements: Backup An estimation of the uncertainty of measurements: Q [g s-1] Pd Heater [W cm-2] T1 [oC] P1 [bar] Subcool_1 p2 [bar] Tsat-p2 [°C] T3 [oC] p3 [bar] ∆pSt [bar] h3 [kJ kg-1] h3Lsat xSat-p3 [-] T3' [°C] Error@3 [°C] hOut xout-stave [-] 0.16 0.30 20.2 3.07 9.1 1.80 13.2 16.8 1.74 0.06 111 14.92 107 1.04 12.2  - 99.37 0.92 0.2 20.4 3.10 9.2 1.82 13.5 14.0 1.75 0.07 108 15.09 1.01 12.4 1.6 84.40 0.75 0.50 1.84 13.8 21.0 0.09 114 1.08 125.74 1.20 0.4 20.3 3.08 1.81 13.3 13.4 1.0 53.94 0.42 3.06 8.8 1.93 15.1 1.76 0.17 15.26 12.5 0.9 74.71 0.65 0.6 2.87 6.8 1.96 15.6 43.81 0.31 2.85 6.6 2.02 16.5 0.26 0.8 57.59 0.46 2.79 5.9 2.03 16.6 0.28 38.75 2.78 5.8 2.11 17.7 1.78 0.33 15.60 1.00 12.8 0.5 49.08 0.36 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? 𝑇 3 = 𝑇 3 ′ = 𝑇 𝑆𝑎𝑡 @ 𝑝 3 𝑇 3 > 𝑇 3 ′ M. Gomez Marzoa ALICE Cooling Meeting - 4th September 2012