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Experimental and numerical investigation of the emergency helium release into the LHC tunnel.

Author(s) : MALECHA Z. M., JEDRUSYNA A., GRABOWSKI M., et al.

Type of article: Article, Case study

Summary

An unexpected ejection of cryogen into large confined spaces can result in hazardous consequences. This paper presents the experimental results of the controlled release of liquid helium into the LHC tunnel at CERN. The experiment was designed to measure the oxygen concentration, temperature, and propagation of the helium-air mixture cloud in the LHC tunnel. This required the usage of novel, in-house manufactured, ultrasonic helium detectors. The experimental results showed an advantage of the ultrasonic sensors over traditional electrochemical sensors. Next, a minimal mathematical model was presented and
implemented numerically. The experimental results contributed to the validation of the numerical model. A number of numerical calculations were performed in order to examine the consequences of a helium spill with different mass flows. This assisted in the evaluation of the critical helium mass flow, above which the oxygen concentration could drop below the safety limit. A satisfactory comparison of the experimental results and numerical calculations showed the accuracy of the assumptions of the proposed
mathematical model.

Details

  • Original title: Experimental and numerical investigation of the emergency helium release into the LHC tunnel.
  • Record ID : 30020888
  • Languages: English
  • Source: Cryogenics - vol. 80
  • Publication date: 2016/09
  • DOI: http://dx.doi.org/10.1016/j.cryogenics.2016.09.005

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