A competitive technique to store large quantities of hydrogen is the cryo-compression of the gas. A deeper understanding of the thermal hazards associated to ignited under-expanded cryogenic releases is fundamental to protect life and prevent property loss. The present study aims at the CFD modelling of thermal hazards beside jet fires with release temperature in the cryogenic range 48-78 K and pressure up to 4 bar abs. The harm level is assessed in terms of thermal dose. The CFD model employs realizable k-ε for turbulence modelling, along with Eddy Dissipation Concept for combustion and Discrete Ordinates model for radiation. The model has been previously validated against experiments by Sandia National Laboratories (SNL) on cryogenic hydrogen fires with release pressure up to 5 bar abs and temperature up to 82 K. Simulations were performed for three experimental tests conducted at SNL. The thermal dose was calculated for several exposure times in the near field to the jet fire. The harm criteria for people were defined according to the thermal dose thresholds for infrared radiation. The maximum exposure time to not be “harmed” at 0.5 m from the flame axis resulted to be lower than 30 s for all the 3 tests. In test 3 (T = 78 K, P = 4 bar abs, m = 0.56 g/s), 60 s exposure resulted in second degree burns within 0.5 m from the jet flame axis. At the same distance, 4 minutes is the maximum exposure time before third degree burns occurrence.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]. Vol. 2: 21-26 April 2019, Saint Petersburg, Russia / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 98,7 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-97.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-97>.