Progress at the large scale CO2 system, Contents Progress at the large scale CO2 system, Results of the small scale CO2 system in the cryolab.

CO2 - Large scale system Joao Noite, Lukasz Zwalinski, Torsten Koettig

CO2 - Large scale system

CO2 - Large scale system

CO2 - Large scale system Location in 158: - Commissioning of the system at 25°C, Possible mass flow rate 1...15 g/s, Run only at ambient temperature at the moment, Next step => accumulator to vary Tsat. Joao Noite, Lukasz Zwalinski, Torsten Koettig

Small scale system in the cryolab CERN: CO2 – Small scale system Small scale system in the cryolab CERN: Test section length: 300 mm, heated part: 150 mm Measurement of the heat transfer coefficient and pressure drop under variation of the following dependencies: Vapor quality x Heat flux q Mass flux G Saturation temperature Tsat Jihao Wu, Daniel Helmer

CO2 - Small scale system Heat transfer coefficient in the flow map (Tsat=263 K, G=300 kg/m2s, q=15kW/m2)

Pressure drop in the flow map (Tsat=263 K, G=300 kg/m2s, q=15kW/m2) CO2 - Scanning the two-phase region Pressure drop in the flow map (Tsat=263 K, G=300 kg/m2s, q=15kW/m2) Pressure drop [mbar] Mass flux [kg/m2s] Vapor quality x

Saturation temperature Tsat CO2 - Scanning the two-phase region Measurement of the heat transfer coefficient and pressure drop under variation of the following dependencies: Vapor quality x Heat flux q Mass flux G Saturation temperature Tsat

Heat flux dependency of the heat coefficient (T=263 K, G=400 kg/m2s) CO2 - Scanning the two-phase region Heat flux dependency of the heat coefficient (T=263 K, G=400 kg/m2s)

Heat flux dependency of the pressure drop(T=263 K, G=400 kg/m2s) CO2 - Scanning the two-phase region Heat flux dependency of the pressure drop(T=263 K, G=400 kg/m2s)

Saturation temperature Tsat CO2 - Scanning the two-phase region Measurement of the heat transfer coefficient and pressure drop under variation of the following dependencies: Vapor quality x Heat flux q Mass flux G Saturation temperature Tsat

Mass flux dependency of the heat coefficient (T=263 K, q=7.5 kW/m2) CO2 - Scanning the two-phase region Mass flux dependency of the heat coefficient (T=263 K, q=7.5 kW/m2)

Mass flux dependency of the pressure drop (T=263 K, q=7.5 kW/m2) CO2 - Scanning the two-phase region Mass flux dependency of the pressure drop (T=263 K, q=7.5 kW/m2)

Saturation temperature Tsat CO2 - Scanning the two-phase region Measurement of the heat transfer coefficient and pressure drop under variation of the following dependencies: Vapor quality x Heat flux q Mass flux G Saturation temperature Tsat

CO2 - Scanning the two-phase region Temperature dependency of the heat coefficient (q=15 kW/m2, G=300 kg/m2s)

Temperature dependency of pressure drop (q=15 kW/m2, G=300 kg/m2s) CO2 - Scanning the two-phase region Temperature dependency of pressure drop (q=15 kW/m2, G=300 kg/m2s)

Paper will be submitted to Int. Journal of Heat and Mass Transfer Resume Reliable test setup to determine heat transfer and pressure drop, Measurements in the whole two phase region are done, Influences of mass flux, heat flux and saturation temperature. Paper will be submitted to Int. Journal of Heat and Mass Transfer

CO2 - Small scale system Instabilities Observed instabilities: J-T expansion into subcooled liquid or x<3% oscillations occur Oscillations are amplified reaching the dryout at around 75 % vapor quality Temperatures below -34 °C