Large scale CO2 setup at HS Esslingen

Christopher Franke, Johannes Kuttler, Tobias Truckses, Sandro Vogrig, Christian WaißFriedrich Haug,Walter Czarnetzki, Stefan Rösler

Content:

1. Collaboration2. Test Setup3. Performance data4. Instrumentation5. Plannings

Collaboration

To ensure a reliable operation of the upgraded cooling system of the CMS pixel detector with CO2 in two-phase flow, the flow stability at the inlet and outlet pipes needs to be investigated by experiments.

The idea was to built up a large scale CO2 cooling system which provides enough cooling power to investigate the behaviour of two-phase flow in big diameter supply tubes.

Determining the state variables (pressure & temperature) and flow visualization respectively at the flow regimes of interest.

The advantage of the CO2 system built up at HS Esslingen is the possibility to apply the different and close to reality „Test Sections“.

Collaboration

➡ Collaboration between CERN and HS Esslingen/ Germany,

department of Mechanical Engineering➡ Initiated by Friedrich Haug Cryolab➡ Assignment of a group of 4-5 student (part time work on

the projekt, 6th semester)➡ Two professors are involved (part time)➡ Subsequent work after each semester

Test Setup

1 2 3 4Temp. in °C

Pressure in bar

Enthalpy in kJ/kg

-40 96 0 -40

10 35 35 10

435 546 200 200

Test Setup

Heater

Heater

HeaterHeater

Hea

ter

Compressor

expansionvalve

oil seperator

cond

ense

r un

it

Test Setup

Performance data

compressor Bock HGX12P/60-4 CO2

• semi-hermetic piston compressor

• displacement: 5,4 m³/h

• max. pressure: 27/42 bar (LP/HP)

• weight: 49 kg

condenser unit Fa. Kältefischer

• refrigerant capacity: 4,0 - 8,7 kW

• refrigerant: R404a

• chiller: Bock HGX22P

• plate heat exchanger

• heat sink: water cooling

Instrumentation

• monitor operating conditions by measuring temp. & pressure

5x along the cycle

Instrumentation

• mass flow measurement by

Coriolis mass flow meter

(Endress+Hausser ProMass 83F,

accuracy 0,4%)

• 4x measurement of surface temperature along the „TestSection“

• measurement of fluid temp. & pressure

at the inlet & outlet of the „TestSection“

by self developed „Bricks“

Plannings

• Commissioning of the setup

• Determine limitations of use

• Implement the flow visualisation

• Startup of experiments (needs to be defined)• in adiabatic and non-adiabatic tubes• at different flow regimes (flow maps)• in user-defined tube geometries• at different orientations• ...

➡ E.g. flow stability

Thank you for your attention!