Laminar burning velocity of gases vented from failed Li-ion batteries

In the last decade, several fires and explosions caused by Li-ion batteries (LIBs) have been reported. This can be attributed to the thermal runaway and catastrophic failures of LIBs that release combustible gases, which when mixed with air can lead to explosions and fires. To address this explosion hazard, we determine the laminar burning velocity (LBV) of three gas compositions associated with Li-ion failure and a pseudo (simplified) gas in a 20-L explosion sphere at 300 K and 100 kPa. This simplified gas avoids toxic gases in experiments and represent the desired explosion characteristics. The LBVs in the case of gas compositions range from approximately 300 to 1050 mm s −1. Additionally, four different reaction models are used to estimate the LBVs of these gas compositions. We compare the theoretical and experimental results to determine the prediction accuracy of the reaction models. All reaction models over- or under-predicted the LBV for the different gas compositions. A recommendation for choosing reaction models is given to predict LBV for various gas compositions. This study's results are intended as input to computational fluid dynamic simulations but can be used directly in safety engineering models.publishedVersio

EXPERIMENTS WITH RELEASE AND IGNITION OF HYDROGEN GAS IN A 3 M LONG CHANNEL

ABSTRACT This paper presents results from laboratory experiments with hydrogen dispersions and explosions in a 3 m long channel. Our objective is to get a better understanding of the phenomena and to develop tools that can analyse hydrogen dispersions and explosions. A total of 5 test series were performed with flow rates of hydrogen from 1.8 dm³/min to 75 dm³/min. The propagation of the combustible hydrogen-air cloud in the channel was observed from high-speed video recordings. The hydrogen-air cloud in the channel behaves as a gravity current and the flow appears to be well described by Froude scaling with a length scale corresponding to the height of a layer of 100 % hydrogen. The Froude numbers observed in the experiments are in good agreement with the theory of "light-fluid intrusion" for gravity currents found in the literature. Numerical simulations with the Flacs code correlate well with the experimental results. The flame propagation indicated that approximately half the height of the channel was filled with combustible mixture. We believe that this Froude scaling can be useful as a tool to analyse the consequences of hydrogen release in buildings, channels and tunnels. NOMENCLATURE Fr Froude number, [-

EXPERIMENTS WITH RELEASE AND IGNITION OF HYDROGEN GAS IN A 3 M LONG CHANNEL

ABSTRACT This paper presents results from laboratory experiments with hydrogen dispersions and explosions in a 3 m long channel. Our objective is to get a better understanding of the phenomena and to develop tools that can analyse hydrogen dispersions and explosions. A total of 5 test series were performed with flow rates of hydrogen from 1.8 dm³/min to 75 dm³/min. The propagation of the combustible hydrogen-air cloud in the channel was observed from high-speed video recordings. The hydrogen-air cloud in the channel behaves as a gravity current and the flow appears to be well described by Froude scaling with a length scale corresponding to the height of a layer of 100 % hydrogen. The Froude numbers observed in the experiments are in good agreement with the theory of "light-fluid intrusion" for gravity currents found in the literature. Numerical simulations with the Flacs code correlate well with the experimental results. The flame propagation indicated that approximately half the height of the channel was filled with combustible mixture. We believe that this Froude scaling can be useful as a tool to analyse the consequences of hydrogen release in buildings, channels and tunnels. NOMENCLATURE Fr Froude number, [-

Experimental investigations effect of water sprays on gas explosions

Authors affiliateed to Chr. Michelsen Institute Bergen (NO)Available from British Library Document Supply Centre- DSC:6244.38(DE-OTH--90-316) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo