13th April 2005R.Bates, QM Measurements of Barrel and EC HEX R. Bates, M. Olcese, B. Gorski, QM for prototype builds

13th April 2005R.Bates, QM Contents Details of the evaporative cooling system Measurements made:  Barrel HEX  EC HEX CERN Prototype QM-1 HEX  Pressure drops over pipe work

13th April 2005 The evaporative system in 175 General design of system close to final design

13th April 2005R.Bates, QM Details of off-detector section

13th April 2005R.Bates, QM Detail of circuit tested Volume and Danfoss meters for massflow measurements Heat liquid after Danfoss to reach 35°C before HEX inlet  Manual heater control PLC controlled proto- heater ELMBs with PVSS monitoring plus some manometer duplication Keller high pressure transducer before capillary

13th April 2005R.Bates, QM Enthalpy Diagram Sub-cooling Boiling in the cooling circuit Final Heater Compression Condensation Pumping Subcooling increases efficiency, i.e. less flow required Expansion in the capillary Psat= exp(T)

13th April 2005R.Bates, QM Why sub-cooling Cooling power = massflow x Enthalpy Max Enthalpy at -25 °C = 102 J/g No sub-cooling, liquid temp = 35°C  Power = massflow x 36 J/g : Endcap  9.6g/s, Barrel  14g/s No sub-cooling, liquid temp = 20 °C  Power = massflow x 53.7 J/g : Endcap  6.5g/s, Barrel  9.5g/s Sub-cooling to -10 °C  Power = massflow x 86.1 J/g  Massflow reduction up to 2.4 times!  Slightly lower as require Xu = 0.9 to cool inlet liquid in HEX Endcap (35°C) = 5.7g/s, Barrel  7.8g/s Reduce the change in massflow as a function of TlbHEX  No sub-cooling  50% increase in massflow  Sub-cooling  <10% increase (small change in TlbCAP)

13th April 2005R.Bates, QM Pressure specifications Design pressure during normal operation at full power in the evaporative circuit (bara) Outlet of liquid pump Outlet of PR Inlet capillary Outlet capillary Detector structures Inlet of BPR Inlet to the compressor Pressure Max system pressure Driven by 40 °C max inlet T specification Driven by -25 °C design T of on detector loop 350mbar pressure drop budget of on vapour side 1bar pressure regulation

13th April 2005R.Bates, QM HEX & massflow HEX efficiency (and Massflow) must be sufficient to cool system with full power Must cope with  TlbHEX = 20°C to 35°C  Sudden power changes in detector structures Limited increase in Massflow as a function of  TlbHEX  Detector power Vapour pressure drops to be as small as possible (  50mbar)

13th April 2005R.Bates, QM Heat Exchangers Design is different for the three sub-detectors due to different layout and geometrical constraints All countercurrent type Pixel: parallel type external. Al inlet and return tubes glued together over 1.5m. Simple design, possible with small power load EC SCT: inlet tube is coiled in spiral inside the return tube over less than 0.4m. Barrel SCT: parallel type internal. Two inlet tubes are routed inside the return tube over a length of 1.5m and parallel to the return tube axis

13th April 2005R.Bates, QM SCT EC heat exchangers Several prototypes made Final design qualified Pressure drop budget is met QMUL is making a final prototype with final tubes

13th April 2005R.Bates, QM Endcap HEX - designs 1 st failed due to boiling inside capillary HEX1 – HEX3 failed due to low efficiency HEX nameDesign typeInternal pipeVapour return Length (mm) ID (mm) OD (mm) Length (mm) ID (mm) Free ID (mm) HEXCapillary inside HEX HEX1CuNi pipe inside HEX HEX2CuNi pipe inside HEX HEX3Cu pipe inside HEX HEX4Cu pipe inside HEX QM-1Cu pipe inside HEX

13th April 2005R.Bates, QM Results with CERN HEX4 Minimum massflow to remove nominal detector power of 346.5W found for HEX = 5.7g/s Inlet liquid temperature of 35°C maintained through out Massflow measured by volume meter Massflow measurement checked with energy balance  Know inlet liquid and outlet vapour pressure/temperature  Know power into the system  Can calculate massflow

Minimum massflow Baseline massflow = 5.7g/s for TlbHEX = 35°C, 100% power

13th April 2005R.Bates, QM Results summary– CERN HEX4 TlbHEX=35C 100% power TlbHEX=20C 0% power Massflow (g/s) TlaHEX Hex eff Xi Xu Massflow Increase = 0.7%

13th April 2005R.Bates, QM Stability checks Tests were performed to confirm that the system is stable  Ran for more than 2 hours without interference  Rapidly (less than 1 minute) increase detector power from 0 to 100%  Repeated measurements to confirm observations

13th April 2005R.Bates, QM 0 to 100% power min massflow

Different HEX orientations All with TlbHEX = 35°C, 100% power V  min massflow (g/s)  PlbCAP (bara)  TlaHEX (°C)  Efficiency (%)  Xi  Xu deg V L V +45deg L

13th April 2005R.Bates, QM Only 2 capillaries open Tested as some disks only have two circuits  Only 2 EC HEXs has 2 capillaries (disk 1) Tested in +45deg as worse case Efficiency of HEX reduced  Does not work for nominal massflow - now 3.98g/s  Minimum stable massflow = 4.4g/s Same flow if use 2 x large capillaries Could use 1large and 1small cap & increase pressure to test  TlaHEX = -20C, HEX eff = 0.92  DP HEX V = 35mbar, DP on cylinder = 46mbar Change in massflow 100%(T=35°C) to 0%(T=20°C)  0.7% increase

13th April 2005R.Bates, QM QM-1 Inlet liquid pipe length reduced by 8% to 2764mm 100% power TlbHEX=35C CERN HEX, 0deg +45deg-45deg 0%, TlbHEX=20C Massflow (+3%) PlbCAPn/a TlaHEX Hex eff Xi Xu Stable at 98% power and massflow of 5.84g/s (2.5% above baseline 5.7g/s) Max massflow 8% above baseline massflow: (+45deg, 0%(T=20) = 6.06g/s)

13th April 2005R.Bates, QM Barrel HEX Contra-flow Two liquid inlet pipes Length  1.5m Vapour in 45 HEX out of page x z -45deg geometry

13th April 2005R.Bates, QM Results Nominal massflow of 7.8g/s shown to remove nominal detector power of 504 W Inlet liquid temperature of 35°C maintained through out Stability checks performed System measured for both ± 45deg Tested with cooling loop & barrel 6 manifold HEX vapour ΔP too high – but manageable

13th April 2005R.Bates, QM Results 100% power (504W) TlbHEX = 35C +45deg geometry-45deg geometry Massflow (g/s)7.8 TlaHEX ( o C) HEX Efficiency Xi0.34 Xu0.98  P vapour (mbar)  P liquid (mbar) Pressure after Cap

13th April 2005R.Bates, QM Changes in massflow for changes in TlbHEX and power Power (%) TlbHEX ( o C) Massflow (g/s) % change in massflow  P vapour (mbar)  P liquid (mbar) TlaHEX ( o C) HEX eff N/A * * Funny seen in the system. The operating conditions for a power cycle 100% to 0% power (TlbHEX = 35°C) resulted in a lower efficiency for the HEX and therefore lower massflows when compared to starting the system up. From start up the massflow for TlbHEX=35°C was 8.8 g/s. Not observed for -45deg geometry. +45deg

13th April 2005R.Bates, QM Efficiency increases with lower TlbHEX XiXu 20C C

13th April 2005R.Bates, QM Highest efficiency up to 75% power – 378W TlbHEX=35C 75% power Massflow = 8.6g/s

13th April 2005R.Bates, QM Stability 0 – 100% power TlaHEX = 9.5C TlbHEX = 35C TvbHEX = -25C TvaHEX = 14C

13th April 2005R.Bates, QM 2hour run

13th April 2005R.Bates, QM System only slightly affected at 75% power Vq=0.75 Vq=0.98

13th April 2005R.Bates, QM Barrel HEX with cooling loop

13th April 2005R.Bates, QM Barrel HEX with cooling loop

13th April 2005R.Bates, QM Barrel HEX/Cooling loop test Tested HEX with real cooling loop  HEX performance the same with cooling loop as with dummy load  Cools first and final module  Pressure drop over cooling loop considerable – results in evaporation temperature changes  ΔP less for lower detector power and lower inlet liquid temperature

13th April 2005R.Bates, QM Cooling loop Press & Temps Coolant Temperature, ( o C) Calculated saturation pressure, bara Measured pressure, bara Start of loop End of loop Start of loop End of loop In exhaust pipe few cm after manifold

13th April 2005R.Bates, QM  P in loop & manifold 100% power  Pman = 280mbar  Ploop = 540mbar  Ptotal = 820mbar

13th April 2005R.Bates, QM Smooth increase in  P as function of outlet vapour quality

13th April 2005R.Bates, QM  P for TlbHEX = 20ºC For m=7.8g/s Vapour quality reduced Pressure drop reduced  Still very high Tevap reduced   T < 3ºC NOTE  If reduce massflow then VQ increase,  P and Tevap rise TlbHEX 35C20C VQ inlet VQ outlet  P TOTAL (mbar)  P loop  P manifold T start of loop T end of loop  T (ºC)

13th April 2005R.Bates, QM Summary of HEX performances Need more liquid at the outlet (higher efficiency) for stability Min flow cooling 100% of power with stable load transients 0%-100%-0% 50% more capacity

13th April 2005R.Bates, QM Pressure drop measurements Pressure drops measured for:  Inlet pipe work ID = 4 mm, Length = 10.8 m  Outlet pipe work ID = 8 mm, Length = 6 m  Final design of Endcap On-cylinder pipe work  Prototype EC and Barrel Heaters  HEX of each design: Liquid inlet & Vapour return  Barrel cooling loop  Barrel HEX to manifold pipe work Final pipe work sizes predicted for  heater exhaust to PPF1/PPF2  PPF2 to PPF3 (PR on racks)

EC Pressure drops - summary FromToLength (mm)ID (mm)Pressure drop (mbar) Inlet PP3PP PP2PPF PPF1Inlet of HEX HEX (1200) Total inlet side (1325.2) Exhaust PPF0Inlet of HEX24636&890 (130) HEX Outlet of HEXInlet of Heater Heater Heater exhaustPPF PPF1PP PP2PP Total return side314.5 (354.5)

Barrel Pressure drops - summary FromToLength (mm)ID (mm)Pressure drop (mbar) Inlet PP3PP PP2PPF PPF1Inlet of HEX HEX Total inlet side623.5 Exhaust Stave ExhaustInlet of HEX HEX170013/ Outlet of HEXInlet of Heater Heater Heater exhaustPP PP2PP Total return side353.4

13th April 2005R.Bates, QM Extra slides

13th April 2005R.Bates, QM Photos The main cooling rig BPR

13th April 2005R.Bates, QM Condenser, volume meter, PLC

13th April 2005R.Bates, QM Power supplies for cooling loop heaters

13th April 2005R.Bates, QM Barrel cooling loop pictures Final cooling loop Barrel 6 manifold Barrel 3 pipe run manifold to HEX 36 ceramic heaters

13th April 2005R.Bates, QM Pictures Capillary into loop Pressure measurements just after capillary Press sense 5cm after manifold on exhaust Temperature sensors on pipe and on heaters Insulations around temp sensors

13th April 2005R.Bates, QM Barrel HEX & cooling loop HEX at -45deg Loop horizontal

13th April 2005R.Bates, QM EC QM HEX prototype First QM EC HEX at CERN

13th April 2005R.Bates, QM Pressure specifications High input P : MinP inlet > P sat (T=40°C) = 12.8bara  MinP inlet = 13bara  P sat (T=35°C) = 11.3bara  MinP inlet = 11.5bara Low evaporating pressure : P(T=-25°C) = 1.67bara Pressure drops  Liquid side Capillary to PR = 1bara PR to cooling rack = 1bara PR range (for flow regulation) = 1bara Pressure from liquid pump = 16bara  Vapour side P min at inlet of BPR = 1.3bara Pressure drop from detector structures to BPR = 350mbara Pressure drop includes drop along Heater, (budget = 50mbar), HEX, on- cylinder pipe work, and rest of pipe work to BPR. Higher massflow implies higher pressure drops in system  BIGGER pipes, bigger Heater etc  And more powerful Heater

13th April 2005R.Bates, QM Number of circuits and capacity Table 1: basic parameters and cooling capacity of the SCT evaporative circuits Numbers of capillaries per circuit Number of circuits Nominal power load Subtotal nominal power load [W][kW] SCT Barrel SCT EC (3 sectors disk) SCT EC (2 sectors disk) TOTAL

13th April 2005R.Bates, QM Barrel +45deg, change in operating conditions of HEX as TlbHEX and power changes