1. Aleksander Kopczyński
Test stand for determination of the heat flux to the cold elements of cryogenic systems in case of the vacuum vessel failure
Aleksander Kopczyński
Ziemowit Malecha
Jarosław Poliński
ICEC27-ICMC 2018
Oxford,

2. Scope Problem’s background
Wroclaw University of Science and Technology test setup description
Experiment methodology discussion
Conclusions

3. Problem’s background
The cryogenic vessels or fluid distribution circuits need to be protected by safety equipment against excessive pressure caused by intensive heat inflow to this elements
Example of Cryogenic Distribution System (ESS) – process lines safety equipment

4. Problem’s background
One of the heat inflow source to be considered in the safety equipment sizing is the incidental ventilation of the vacuum vessel with atmospheric air.
300 K
20-90 K
4.2 K

5. Problem’s background
The heat flux with atmospheric air inflow to helium temperature elements has been already experimentally determined as 3.7 – 5.0 kW/m2 [1,2,3], The thermal shields are covered from external side with layers of MLI. The heat flux through the MLI side can be expected as 0.25 kW/m2 [4].
QAir-He= kW/m2
QAir-TS_Bare=???
QAir-TS_MLI=0.25 kW/m2

6. Problem’s background TS temperature Gas convection Condensation
Air_Liq
TS temperature
Condensation
Air_III
Solid deposition

7. Problem’s background
Schematic temperature profile during vacuum degradation failure (based on [7]), where: : I- vacuum chamber section; II- liquid deposit section; III- solid deposit section; IV- cold wall section; V- liquid cryogen section

8. Wroclaw University of Science and Technology cryostat
Chosen physical properties of possible gases selected for the experiment
Boiling temperature, K
Triple point temperature, K
Heat of evaporation, kJ/kg
Heat of melting, kJ/kg
Helium
4.23 -
20.8
Air
78.9
59.8
205.5  -
Nitrogen
77.3
63.3
199
25.8
Argon
83.8
87.3
163
29.6

9. Wroclaw University of Science and Technology cryostat

10. Wroclaw University of Science and Technology cryostat
Vacuum vessel
Horizontal length
3600 mm
Horizontal diameter
320 mm
Vertical length
1900 mm
Vertical diameter
506 mm
Volume
530 l

11. Wroclaw University of Science and Technology cryostat
Vacuum vessel
Horizontal length
3600 mm
Horizontal diameter
320 mm
Vertical length
1900 mm
Vertical diameter
506 mm
Volume
530 l
Nitrogen tank
Volume
13 l

12. Wroclaw University of Science and Technology cryostat
Cold vessel
Horizontal length
3350 mm
Horizontal diameter
115 mm
Vertical length
820 mm
Vertical diameter
172 mm
Heat transfer area
1.90 m2

13. Wroclaw University of Science and Technology cryostat

14. Wroclaw University of Science and Technology cryostat

15. Helium vessel heat transfer measurement
Isochoric change of state
(8)
Isobaric change of state
(9)

16. Final remarks

17. Thank you for the attention!

18. References
Lehmann, W., Zahn , G., “Safety Aspects for LHe Cryostats and LHe Transport Containers” Proceedings of International Cryogenic Engineering Conference 7, IPC Science and Technology Press, London, 1978, pp
Will Francis, Mike Tupper, Stephen Harrison, Conformable tile method of applying CRYOCOAT™ UL79 insulation to cryogenic tanks.
Harrison, S. M., “Loss of Vacuum Experiments on a Superfluid Helium Vessel” in IEEE Transactions on Applied Superconductivity, IEEE, 2002, pp
G.F. Xie, X.D. Li, R.S. Wang , Study on the heat transfer of high-vacuum-multilayer-insulation tank after sudden, catastrophic loss of insulating vacuum, Cryogenics 50 (2010) 682–687
M. Chorowski, J. Fydrych, Z. Modlinski, J. Polinski, L. Tavian, J. Wach, Upgrade on risk analysis following the incident in the LHC sector 3-4, CERN/ATS/Note/2010/033 (TECH),
Heidt C., Grohmann S., Süßer, M. Modeling the Pressure Increase in Liquid Helium Cryostats after Failure of the Insulating Vacuum, 2014 AIP Conf. Proc. 1573,
Zoller C., Experimental Investigation and Modelling of Incidents in Liquid Helium Cryostats, PhD Thesis, Karlsruhe Institute of Technology, Karlsruhe