Phase 1 FPix Cooling Tube Testing Erik Voirin, C.M. Lei, Harry Cheung, Stefan Gruenendahl (FNAL) Kirk Arndt, Qiuguang Liu (Purdue) Phase 1 FPIX cooling status Feb Phase 1 FPix cooling loops Phase 1 FPIX cooling status Feb Baseline design is 1 main line for first half-disk, 1 main line for 2 nd and 3 rd half-disks. One single loop was tested, with the DC-DC, PC and HD (1.366 mm ID) sections in series. 45 W pre-heating power for DC-DC/PC and 168 W power for HD was applied. Steady flow with sub-cooled CO2 at -20C inlet as assumed in Joao calculations was difficult to achieve. Dry-out appeared if the delta P was set too low (2.75 bar in Joaos calculation). 3.5 bar min. was required for stable flow. The measured temperatures across the DC- DC/PC and HD heat loads are comparable to temperatures calculated by Joao. Repeated the testing in Dec with: - larger ID tubing (1.416 mm) - different heat load conditions: Status Updates Nov 123 Full-Loop Test Nov Ready for data taking, W During data taking, WMax, W HD DC-DC PC FPix Full Loop Test Nov2012 Liquid P Phase 1 FPIX cooling status Feb Running single phase with no heat load, Joao calculated dP = 0.94 bar with 2 g/s flow and 1.9 bar with 3 g/s flow, compared to 1.5 bar with 1.9 g/s flow and 3.2 bar with 3 g/s flow in the full-loop test. Full-Loop Test Dec Full-loop tubing inside FPIX for single Half-Disk 1.416mm ID tubing in the HD rings section (i.e. the largest tubing available that does not require a redesign of the 2.0 mm thick HD rings) Platinum RTDs attached to the tube, calibrated in place by running sub-cooled and saturated CO 2 through the unheated cooling tube at several differential pressures and applying offsets to the RTDs to display the correct temperatures, with the same offsets being used throughout all tests. All temperature results were also offset to show exactly -20C at the exit, so slight differences in upstream temperature could be more easily compared; exit temperatures were very near and stable at - 20C throughout all testing anyway. Result temperatures are the compiled average of many runs. These runs were only used for averaging once steady state was reached. Phase 1 FPIX cooling status Feb ID measurements of the HD tubing The average inner diameter = mm. (End views of 3/4 long cut pieces of the tubing.) Phase 1 FPIX cooling status Feb Schematic of experimental setup Phase 1 FPIX cooling status Feb /4" tubing joint0 Tubing 2.064T 1102 Tubing 2.064T 2737 Tubing 2.064heat wire813 Tubing 2.064T Tubing 2.064heat wire2629 Tubing 2.064T Tubing 2.064T Tubing 2.064heat wire4324 Tubing 2.064heat wire5245 joint 5309 Tubing 1.416T Tubing 1.416T Tubing 1.416heat wire6896 Tubing 1.416T Tubing 1.416T Tubing 1.416T joint 8522 Tubing 2.693heat wire8588 Tubing 2.693T /4" tubing joint10598 RTD and heat wire placement (in mm) along the tubing Wires for DC-DC converter, Port Card/POH and HD heat loads soldered to tubes Test setup and equipment Phase 1 FPIX cooling status Feb FPix Full Loop Test Dec2012 Liquid P Phase 1 FPIX cooling status Feb With zero heat load, our measured delta P = ~1.3 bar at 2 g/s flow (right) is higher than the calculated delta P = 0.82 bar at 2 g/s flow (left) Running Single Phase through the entire test loop was not possible since there is always an ambient heat load (estimate ~20W) and the CO2 becomes saturated at some point throughout the tubing. Ready for Data Taking results Phase 1 FPIX cooling status Feb CO2 Plant Supply Temp (C) CO2 Plant Return Temp (C) Tubing temperatures at stable flow with ready for data taking heat load During Data Taking results Phase 1 FPIX cooling status Feb CO2 Plant Supply Temp (C) CO2 Plant Return Temp (C) Tubing temperatures at stable flow with during data taking heat load Maximum Heat Load results Phase 1 FPIX cooling status Feb CO2 Plant Supply Temp (C) CO2 Plant Return Temp (C) To reach steady flow, we increased the Delta P by pumping harder. The CO2 was sub cooled as much as possible before the run. As the data was taken, the inlet warmed up because we were adding heat from the pump to reach 4.25 Bar Delta P. Transient Unstable Dry out flow with Max. Heat Load Phase 1 FPIX cooling status Feb Data at 3.75 to 3.9 Bar Delta P, which yielded unstable dry out flow conditions HD Tubing Pressure Drop Phase 1 FPIX cooling status Feb Total loop DP Outlet Pressure (-20C) Support Tube Temp Support Tube Sat Press HD Pressure Drop HD percent of total DP barbar-adeg Cbar-abar% Max Heat Load % During Data Taking % Ready for Data Taking % In conclusion, the full-loop test of the series configuration with mm ID tubing in the Half Disk section shows stable flow with the nominal heat load during data taking at a Delta P > 3.25 bar, and stable flow with the maximum heat load at Delta P > 4.25 bar. However, our pump was unable to produce the flow Joao calculated for sufficient margin to dry out. This table from Erik shows that the measured DP through the Half Disk dominates the overall DP through the full loop. Based on the effect diameter has on pressure drop, Erik estimates we need HD tubes around ~ mm ID to achieve ~2 bar DP with our current full-loop series configuration. Alternative: to lower dP, outer and inner HD assemblies are split into parallel loops Phase 1 FPIX cooling status Feb Near Term Testing with CO2 system at FNAL Add concentric heat exchanger at the full-loop inlet/outlet. Full-loop testing: Parallel flow for Outer assembly: 1.87 m long HD tubing with ID 1.42 mm, same supply and return tubes, all connected in series. Parallel flow for Inner assembly: 1.33 m long HD tubing with ID 1.42 mm, same supply and return tubes, all connected in series. Series flow for Outer + Inner assembly: 3.2 m long HD tubing with ID 1.63mm, same supply and return tubes, all connected in series. Current pump limits the flow tests we can perform (maximum delta P ~4.5 bar). We need a stronger pump to test full-loops including capillaries. Phase 1 FPIX cooling status Feb Action Items from Upgrade FPIX mech. meeting 4-Jan-2013 We would like to have a meeting w/ cooling system designers at CERN soon. CMS meeting week of February 4, some people should go. Do a full-loop test with bigger ID HD tube. Do a full-loop test of 2 loops with 1.4 mm ID HD tubes in parallel. Get feedback regarding recent full-loop tests and serial 1.6mm vs. parallel 1.4mm loops from CERN. Need to measure the position of each temperature sensor along the full-loop Need to measure full-loop performance w/ +15 C coolant. Phase 1 FPIX cooling status Feb Closed questions What is the purpose of all the valves in the full cooling system diagram? Some are related to start-up of cooling system from warm. Bigger ID tube in series vs. more lines in parallel --> both would give better margin to dry out. Can dP across main lines be different? Yes, can change each main line dP (post- valve). How much convection cooling? Little to none in the sealed detector volume of dry air. Are we sub cooled into detector? Yes, but not without a heat exchanger. Does the fluid dP vs. mass flow behave linearly? Erik says there are both linear and quadratic regions. What is the error in the measured flow? Could we be off by a factor of 2? There should be 10% measurement error in liquid phase on FNAL flow meter. Run serial lines through all half-disks? Still requires larger ID HD tubingthis idea discarded. Is there a way to eliminate possibility of constrictions (there are several soldered couplings)? dT shows no discontinuity over half-discs - Eric says couplings are okay. Phase 1 FPIX cooling status Feb Open questions 1)How much dry purge air flow could be supplied? 2)Tendency to present Calculator correlations that are the best ones? Sometimes off of experiment by ~30%? 3)Can we run +15 C at Fermilab? Depends on pump & system available? 4)What is the overall target dP (including capillary) for FPIX loops? 5)Analysis of FPIX HD loop (from CO2 Cooling plant PRR in May-2012) showed 213W -20 C and +15 C (what tube ID was used in these calcs?) 6)Is 137W enough cooling during insertion/commissioning? 7)Can we measure liquid CO2 heat gain to aid in determining flow rate? 8)Can turn off ROC power, but not sensor HV. What happens? 9)How much room do we have for capillaries? Find the real volume available at PP0 during LS1 access. 10)Problems of splitting lines into parallel? Increase number of couplings, simplicity, how to best divide main lines? 11)What is the status of BPIX cooling tests? Phase 1 FPIX cooling status Feb Backup Slides Phase 1 FPIX cooling status Feb Phase 1 FPIX cooling status Feb Phase 1 FPIX cooling status Feb Phase 1 FPIX cooling status Feb Phase 1 FPIX cooling status Feb