Experimental Parameters of Ignited Congestion Experiments of Liquid Hydrogen in the PRESLHY Project

Liquid hydrogen (LH2) has the potential to form part of the UK energy strategy in the future and therefore could see widespread use due to the relatively high energy density when compared to other renewable energy sources. To study the feasibility of this, the European Fuel Cells and Hydrogen Joint Undertaking (FCH JU) funded project PRESLHY undertook pre-normative research for the safe use of cryogenic LH2 in non-industrial settings. Several key scenarios were identified as knowledge gaps, and both theoretical and experimental studies were conducted to provide insight into these scenarios. This included experiments studying the effect of congestion on an ignited hydrogen plume that develops from a release of LH2; this paper describes the objectives, experimental setup, and a summary of the results from these activities. Characterisation of the LH2 release, hydrogen concentration and temperatures measurements within the resulting gas cloud was undertaken along with pressure measurements both within the cloud and further afield. Various release conditions and congestion levels were studied. Results showed that at high levels of congestion, increased overpressures occurred with the higher flow rates studied, including one high order event. Data generated from these experiments is being taken forward to generate and validate theoretical models, ultimately to contribute to the development of regulations, codes, and standards (RCS) for LH2."