Ceiling radiation heat flux and downward received radiation heat flux of methane jet fire with hydrogen addition.

Radiation and flame scale characteristics of ceiling jet are important key elements, which are related to the safety of hydrogen energy transport. In this study, the flame radiation characteristics caused by hydrogen-blended natural gas (mixed gas) pipeline leakage fire were investigated experimentally. The effects of heat release rate, hydrogen addition ratio, nozzle diameter and source-ceiling height are considered. The flame shape of the ceiling jet fire is modeled by a cylinder cone and a cylindrical model. The WSGGM model is applied to calculate the flame emissivity. The flame emissivity is quantized by the equivalent diameter and gas type. The flame emissivity, downward received radiative heat flux and radiative heat flux under ceiling increase with the increase of hydrogen addition ratio. The view factor is calculated by the solid flame model. Moreover, the calculated flame radiative heat flux is in a favorable agreement with experimental results. The research results may provide reference for risk assessment of hydrogen mixing. • Effect of H 2 on flame radiation of CH 4 jet fire is studied experimentally. • Fame shape of ceiling jet was modeled by the cylinder cone and a cylindrical model. • A mathematical model for the flame emissivity estimation is proposed. • A prediction model of the flame radiation the gas mixture is reported. [ABSTRACT FROM AUTHOR]