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Status of CO2 cooling. CMS Upgrade Workshop FNAL. Participating places (1). RWTH Aachen – Lutz Feld, Michael Wlochal, Jennifer Merz IPN Lyon – Nick Lumb, Didier Contardo University Karlsruhe – Wim de Boer et al. Fermilab – Simon Kwan, Richard Schmitt, Terry Tope, Kirk Arndt.
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Status of CO2 cooling CMS Upgrade Workshop FNAL Hans Postema - CERN
Participating places (1) • RWTH Aachen – Lutz Feld, Michael Wlochal, Jennifer Merz • IPN Lyon – Nick Lumb, Didier Contardo • University Karlsruhe – Wim de Boer et al. • Fermilab – Simon Kwan, Richard Schmitt, Terry Tope, Kirk Arndt Hans Postema - CERN
Participating places (2) • PSI – Roland Horisberger • CERN Cryolab – Friedrich Haug, Jihao Wu, Torsten Koettig, Christopher Franke • University Esslingen – Walter Czarnetzki, Stefan Roesler • CERN DT group – Joao Noite, Antti Onnela, Paolo Petagna, Paola Tropea, Hans Postema - CERN
Participating places (3) • NIKHEF Atlas – Bart Verlaat, Auke-Pieter Colijn • SLAC Atlas – Marco Oriunno • CERN Atlas – Danilo Giugni, Jan Godlewski, Jose Direita • EPFL Lausanne – John Thome et al. • CERN CMS – Duccio Abbaneo, Hans Postema Hans Postema - CERN
CO2 Full scale setup • Following the example of the LHCb cooling plant, we will build a full scale setup for testing purposes • Setup based upon CMS-TEC cooling plant provided by Karlsruhe • R404 chiller has cooling power of 4 kW at -35 C • System uses Lewa pump and SWEP heat exchanger also provided by Karlsruhe Hans Postema - CERN
LHCb schematic Hans Postema - CERN
Engineering • Collaboration, involving people from NIKHEF, CERN-Atlas, CERN-DT, CERN-Cryolab, CERN-CMS • Schematic created in August, finalized and approved in September. • Parts list created in August, approved, except for a few components. • Budgets identified, ordering has started. Hans Postema - CERN
Schematic Hans Postema - CERN
CMS-TEC cooling plant Hans Postema - CERN
LEWA pump Hans Postema - CERN
SWEP heat exchanger Hans Postema - CERN
Conclusions • Full agreement on schematic (P&I) • Detail design is advancing • Budgets agreed and available • Ordering has started • Contact with CERN safety established • In principle no serious obstacles • Will work together to obtain certification • Project is advancing at full speed Hans Postema - CERN
TE-CRG-CI CERN Cryolab • CO2 cooling for pixel detectors • Investigation of heat transfer Christopher Franke, Torsten Köttig, Jihao Wu, Friedrich Haug
Content: • Objectives of the study • Test setup • Measurement conditions • Investigation tube diameter • Summary
Objectives of the study Experimental verification of 2-phase CO2 flow regimes and stability criteria of CO2 flow in minichannels suitable for cooling of the upgraded pixel detector of CMS. Establish a rather comprehensive experimental database in the range of relevant mass flux and heat flux α = f(x,q,G,Tsat). Validation of existing correlations for heat transfer coefficient and pressure drop. If necessary, adapt existing correlations to the database at the range of interest.
Test setup Cooling cycle schematic and log(p)-h diagram 8
Test setup Piping and Instrumentation Diagram
Test setup • Operating temperatures -40°C to -5°C • Mass flow up to 1.5 g/s • Heat flux at test section up to 30 kW/m² • Tube diameter (test section) up to 2.0 mm • Design pressure of the setup 100 bar • Cooling power Pulse Tube Cryocooler 150W@225K • Insulation vacuum 5⋅10-5 mbar
flow direction Test setup • Stainless steel • Length of the actual test section (heated part) • l = 0.15 m • Inner diameter di = 1.4 mm • Wall thickness s = 120 μm • Max. heat flow QTS = 30 W
Measurement conditions 1. Saturation Temperatures: Change in saturation temperature causes a change of the fluid properties which on the other hand influence the flow pattern and heat transfer coefficient respectively! • Following fluid properties are used for calculation: • Density ρ (liquid and gas phase) • Dynamic viscosity η (liquid and gas phase) • Surface tension σ (liquid phase) • Latent heat of vapourization hLV Proposed temperature levels for measurement:
Measurement conditions 1. Saturation Temperature: ΔT = 25 K Δσ = 5,4E-3 N/m surface tension in N/m temperature in °C
Measurement conditions 2. Mass flow (density): Change in mass flow m and mass flow density G respectively influences the flow pattern which on the other hand determine the heat transfer coefficient! Proposed mass flow (density) steps for measurement:
Measurement conditions 2. Mass flow (density):
Measurement conditions 3. Heat flux test section: Change in heat flux and influences the quality factor where dryout occure. • There are 2 theoretical heat flux thresholds: • Onset of nucleate boiling qONB = 1 kW/m² (VDI Wärmeatlas) • Critical heat flux qcrit = 794 kW/m² (S.S. Kutateladze) Proposed heat flux levels for measurement:
Measurement conditions 3. Heat flux test section:
0,05 ≤ x ≤ 1 Δx ≈ 0,025 4 252 x 7 = cases (7) x 9 (441) Measurement conditions Due to CMS requirements of 150W@5.5m (4.1W@0.15m) at -12°C, tube diameter 1.4 mm the following measuring plan is proposed.
Investigation tube diameter Inner diameter Wall thickness
Summary • Test session for 1.4 mm inner diameter tube in horizontal • orientation (according to CMS requirements) • This results an outcome of 252 (441) cases α = f(x) • Good database for comparison with existing flow maps • Good database for comparison with existing calculation models • for heat transfer coefficient • Extensive commissioning and validation of the setup
Physics Department Detector Technology Group Pixel CO2 Cooling Test Status João Noite PH-DT
CO2 Cooling Test Status • 1.4mm ID, 5.5m length cooling pipe tested in different heat loads and flow conditions. • Available empirical models for two phase pressure drop prediction were used and compared with experimental data. • Upgrades on the test setup are being made in order to improve the measurements. • Pixel cooling pipe mockup provided by PSI will be tested during the following weeks. João Noite PH-DT
PROPORTIONAL RELIEF VALVE PRESSURE GAUGE VENT TO ATMOSPHERE WATER BATH HEATER CONCENTRIC TUBE HEAT EXCHANGER METERING VALVE OPTIONAL CAPILLARY TUBE MASSFLOW METER CO2 BOTTLE WITH PLUNGER DETECTOR TUBE WITH ELECTRIC HEATING CO2 Cooling Test Setup João Noite PH-DT
p-h Diagram HEX Pressure [Bar] Detector HEX Water Bath Heater Enthalpy [KJ/Kg] João Noite PH-DT
Latest Results João Noite PH-DT
Latest Results João Noite PH-DT
Latest Results João Noite PH-DT
Test Stability Stable Readings Unstable Readings João Noite PH-DT