Experimental Study on Flame Characteristics of Cryogenic Hydrogen Jet Fire

In this work, cryogenic hydrogen fires at fixed pressures and various initial temperatures were investigated experimentally. Flame length, width, heat fluxes and temperatures in down-stream regions were measured for the scenarios with 1.6-3 mm jet nozzle, 106 to 273 K, 2-5 barabs. The results show that the flame size is related to not only the jet nozzle diameter but also the release pressure and initial temperature. The correlations of normalized flame length and width are proposed with the stagnation pressure and the ratio of ambient and stagnation temperatures. Under constant pressure, the flame size, total radiative power and radiation fraction increase with the decrease of temperature, due to lower choked flow velocity and higher density of cryogenic hydrogen. The correlation of radiation fraction proposed by Molina et al. at room temperature is not suitable to predict the cryogenic hydrogen jet fires. Based on piecewise polynomial law