SoA Release & Mixing. RPW Meeting, 18 Sept 2018, Buxton, UK Alexandros Venetsanos (NCSRD) Pre-normative REsearch for Safe use of Liquid HYdrogen

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1 SoA Release & Mixing RPW Meeting, 18 Sept 2018, Buxton, UK Alexandros Venetsanos (NCSRD) Pre-normative REsearch for Safe use of Liquid HYdrogen 1 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

2 Presentation Outline Review experimental data on cryogenic H 2 release & dispersion Review model validation efforts Identify weak points Identify gaps PRESLHY planned tests 2 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

3 Classification of Releases Injection types Friedrich at al. (IJHE, 2012) Kobayashi et al. (IJHE, 2018) 3 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

4 Overview of experiments LH2 / LHe two-phase expanded releases Experiment Reference 4 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK Spill volume (L) Spill duration (s) Flow Rate Wind (m/s) (kg/s) Tank pressure (bar) Humidi ty (%) Diamet er (cm) NASA-6 / US Witcofski and Chirivella (1984) at 10 m INERIS Lhe / 1.5 and 2 to 5.5 at Proust et al. (2001) FR 2.1 3m BAM / GE L. Marinescu-Pasoi, B. Sturm (1994) m/s 7 97 HSL / UK Hooker et al. (ICHS-4, 2011) at 2.5m Subcooled liquid / Gaseous / Supercritical UnderExpanded Releases Performed by Reference Storage P (bar) Storage T (K) Diameter (mm) NASA / US Simoneau and Hendricks (1979) 12.9 to to KIT / GE Veser et al. (2011) 5 to and 35 1, 2 and 4 KIT / GE Xiao et al. (2012) 8.25 and and 2 KIT / GE Friedrich at al. (2012) 7 to to and 1.0 SANDIA / US Hecht and Panda (2018) 2 to 5 48 to 63 1 and 1.25 SANDIA / US Panda and Hecht (2018) ISAS / JPN Kobayashi et al. (IJHE, 2018) , 0.4, 0.7, 1.0 ISAS / JPN Kobayashi et al. (IJHE, 2018) , 0.4, 0.7 Nagasaki Nakamichi et al. (Cryogenics, to 2.0 R&D / JPN 2008) L/min

5 LH 2 two-phase expanded releases NASA-6 LH2 spills, Witcofski and Chirivella (1984) Various modeling approaches, including pool spreading FLACS, Middha et al (2011) LAuV, Verfondern and Dienhart, (2007) Experiment Stability F Stability D ADREA-HF Venetsanos and Bartzis (2007) FLUENT, Jin et al. (2017) 5 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

6 LHe two-phase expanded releases INERIS spills, Proust et al. (2001) More than 100 sensors were installed on a vertical rectangular frame (60 m x 130 m) made up with the steel ropes Not simulated up to now. 6 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

7 LH 2 two-phase expanded releases The BAM experiments Simulations Staharas et al. (IJHE, 2000) using ADREA-HF code and by Middha et al (IJHE, 2011), FLACS 7 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

8 LH 2 two-phase expanded releases Dienhart, (FZJ Rep,1995) Pool spreading simulations Verfondern and Dienhart, (IJHE, 2007) using LAuV code 5 l/s for 62 s on water 6 l/s for 62 s on solid aluminium surface 8 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

9 LH 2 two-phase expanded releases HSL experiments, Hooker et al. (ICHS-4, 2011) Simulations by Ichard et al. (IJHE, 2012), Giannissi et al. (IJHE, 2014), Giannissi and Venetsanos (IJHE, 2018) ADREA-HF Test 7 Minimum experimental temperature versus predictions Height 0.75 m ADREA-HF FLACS 9 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

10 Subcooled liquid H 2 under-expanded releases Simoneau and Hendricks (NASA Tech. Pap., 1979) Simulations by Travis et al.(ijhe, 2012) with HDE, HNEM (left) Venetsanos and Giannissi (IJHE, 2017) with HEM 10 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

11 Gaseous & supercritical H 2 under-expanded releases Xiao et al. (IJHE, 2012) 8.25 and 32 bar, 80 K No deviations of cryogenic h2 axial concentration decay law from gaseous h2 law 11 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

12 Supercritical H 2 under-expanded releases Friedrich at al. (IJHE, 2012) Deviations of cryogenic h2 axial concentration decay law from ambient gaseous law Discrepancies between discharge modeling and experiments, Venetsanos and Giannissi (2017) 12 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

13 Supercritical H 2 under-expanded releases Kobayashi et al. (IJHE, 2018) experiments Injection from region 3 to 2 No liquid phase during discharge Joule-Thomson expansion accurately predicts release temperature Dense core formed in the supercritical jet The boundary where the hydrogen jet becomes visible exists near the Widom line, which is a saturated vapor pressure line extended to the supercritical side Injection types 13 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

14 Supercritical H 2 under-expanded releases Kobayashi et al. (IJHE, 2018) experiments Flow rate with Bernoulli equation for liquid was found to be appropriate with Cd=0.6 for cryogenic condition An empirical formula of the 1% concentration distance for the cryogenic hydrogen system was newly presented 14 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

15 Cryogenic Gaseous H 2 under-expanded releases Hecht and Panda (IJHE, 2018) The average centerline mass fraction was observed to decay at a rate similar to room temperature hydrogen jets, in contrast to Friedrich et al.(2012) The half-width of the Gaussian profiles of mass fraction were observed to spread more slowly than for room temperature hydrogen. These observations would suggest that the velocity decay along the centerline will be slower for cryogenic hydrogen than for warmer hydrogen Simulations with ColdPlume 15 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

16 Weak points in experiments Unclear release conditions Need to know T, P and vapor quality at nozzle exit Release momentum not measured Sometimes, doubts on the discharge rates Limited instrumentation Large variability or limited info about meteorological conditions Only few concentrations and temperatures No velocities or fluctuations No rainout or droplet size measurements 16 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

17 Gaps related to cryogenic H2 Under-expanded release & dispersion from LH2 storage (saturated or sub-cooled conditions) Storage Blowdown BLEVE Droplet sizes and Rainout Condensation / freezing of air Pool evaporation & ground heat transfer Structure of two-phase jets close to the release Cryogenic axial decay law versus ambient temperature decay law Impinging jets Physical properties of multiphase mixtures of H2, O2, N2 and H20 17 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

18 Experimental plans (HSL) LH 2 expanded two phase releases Rainout tests Release Orientation Release Height Orifice Diameter Horizontal 0.50 m 1 Horizontal 0.50 m ½ Horizontal 0.50 m ¼ Horizontal 1.50 m 1 Horizontal 1.50 m ½ Horizontal 1.50 m ¼ Vertically upward NA ½ Vertically downward 0.50 m ½ Horizontal into baffle 0.50 m ½ 18 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

19 Experimental plans (KIT) Discharge experiments (Alternative Approach-1) No initial release of LH2 possible with DISCHA facility Approach to model LH2-release by set of experiments: Warm release of GH2 Cold (80 K) release of GH2 Warm release of GN2 Cold (77 K) release of LN2 Test parameters 4 initial (over-)pressures in the range from 1 bar to 200 bar, 4 initial temperatures in the range from 80 Kto 200 K (or up to 0 C or ambient temperature if desired), 4 circular aperture-sizes in the diameter-range from 0,5 to 4 mm, 2 nozzle positions (upper and lower port) Surrounding Sensors on the jet axis: 3 H2-Sensors for concentration measurements, 3 Thermocouples Photo-/Video-Observation 19 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

20 Experimental plans (KIT) Discharge experiments (Alternative Approach-2) Release of LH2 from cryogenic vessel But only much lower reservoir-pressures (<< 200 bar) possible 20 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK

21 Experimental plans (KIT) LH2 Pool experiments Main objective: investigate evaporation rate from an LH2 pool and the cold gas mixing phenomena in the near field above the pool (validation of pool models and CFD dispersion models) Measurements of temperature profiles, atmospheric environment conditions (temperature, pressure, humidity) Parameters: solid / porous ground Concerns: It seems to be almost impossible to generate a pool of LH2 with a surface of 1 m² with a reasonable budget for the enormous amount of LH2 that has to be spilled. If the pool is generated the atmosphere around it will consist of gaseous H2 with traces of other gases Desired conditions and parameter settings have to be fixed clearly to allow reliable planning of the facility! 21 PRESLHY RPW Meeting, 18 Sept 2018, Buxton, UK