Advanced European Infrastructures for Detectors at Accelerators New

Advanced European Infrastructures for Detectors at Accelerators New measurements on CO 2 boiling in mini- and micro- channels at CERN April 2 nd 2019 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 Paolo Petagna D. Hellenschmidt, M. Bomben, G. Calderini, M. Boscardin, M. Crivellari, S. Ronchin This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654168.

Reminder: CERN set-up 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 2

Results for ID = 1 mm & 2 mm HTC @ x = 0. 3 Surface power Density =1 W/cm 2 & ID = 1 mm -> q = 32 k. W/m 2 Surface power Density =1 W/cm 2 & ID = 2 mm -> q = 16 k. W/m 2 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 3

Results for ID = 1 mm & 2 mm Dp @ x = 0. 3 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 4

Example of comparisons with correlations (HTC) T=+15 °C T=0 °C T=-15 °C 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 5

Example of comparisons with correlations (Dp) 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 6

High speed camera insight 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 7

Boiling pattern vs. T Position 1 TOP: T = + 15 °C Images: 13 600 fps BOT: T = - 25 °C Flow rate = 0. 3 g/s Chip power = 3 W/cm 2 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 8

Now that we are peeping… “Macro” zoom at position 1 Images: 90 000 fps Flow rate = 0. 3 g/s Chip power = 3 W/cm 2 T = +5 °C Traces of boiling onset Some nice features made possible only by the use of a high pressure refrigerant and (for the time being) silicon Backward facing step induces flash boiling and prevent backflow Stable nucleate boiling with high interactions at walls immediately triggered 13 June 2021 already in the capillary: saturation attained 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 9

More interesting effects “Macro” zoom at position 2 Images: 61 200 fps Flow rate = 0. 3 g/s Chip power = 3 W/cm 2 T = +15 °C Some flow pulsation visible Good for HTC enhancement Induces vibrational forces appear negligible… but let’s have some measurements taken in the new Oxford facility! Bends enhance the mixing and extract energy from the flow locking and increasing boiling 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 10

Cumulative design effect Inlet/outlet comparison Images: 67 500 fps Flow rate = 0. 3 g/s Chip power = 3 W/cm 2 TOP: T = + 15 °C BOT: T = - 25 °C CO 2 IN Due to the high confinement (? ) and to the design, the boiling pattern is very much dependent on T at start, but MUCH LESS once developed CO 2 OUT CO 2 IN CO 2 OUT 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 11

Nice feature of microchannel cold plate Not only the TFM of a microchannel cold plate is much lower than TFM of any other technology, but it stay basically constant with Tsat (i. e. in this case HTC is much less dependent on Tsat) 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 12

Finally publishing! D. Hellenschmidt, M. Bomben, G. Calderini, P. Petagna, New insights on boiling carbon dioxide flow in mini- and micro-channels for optimal silicon detector cooling, VCI 2019 (poster presentation) D. Hellenschmidt, M. Bomben, G. Calderini, M. Boscardin, M. Crivellari, S. Ronchin, P. Petagna, New insights on boiling carbon dioxide flow in mini- and micro-channels for optimal silicon detector cooling, NIM-A (submitted) D. Hellenschmidt, P. Petagna, Saturation temperature effects on the boiling properties of carbon dioxide in mini- and micro-channels, ICMF 2019 (oral presentation) Data being produced, extracted, processed (sometimes even understood…): several publications in preparation 13 June 2021 4 th AIDA-2020 Annual Meeting Oxford, Apr 2 nd – 5 th 2019 13