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Thermal radiation from vapour cloud explosions |
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| Institution: | 1. Department of Mechanical Engineering, Imperial College, Exhibition Road, London SW7 2AZ, United Kingdom;2. Health & Safety Laboratory, Harpur Hill, Buxton SK17 9JN, United Kingdom;1. State Key Laboratory of Low-Dimensional Physics and Department of Physics, Tsinghua University, Beijing 100084, China;2. Collaborative Innovation Center of Quantum Matter, Beijing 100084, China;3. Tsinghua National Laboratory For Information Science and Technology, Beijing 100084, China;4. Department of Chemistry, National Taiwan University, Taipei City 106, Taiwan;1. Research Institute of New Energy Vehicle Technology, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, PR China;2. School of Automobile and Transportation, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, PR China;3. Department of Mathematics, Changchun Normal University, Changchun, Jilin 518055, PR China;4. School of Architectural Engineering, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, PR China;5. School of Urban Planning and Design, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, PR China;6. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, PR China;7. Department of Civil and Architectural Engineering, City University of Hong Kong, 999077 Hong Kong, PR China;1. Centre for Studies on Technological Risk (CERTEC), Department of Chemical Engineering, Universitat Politècnica de Catalunya, Diagonal, 647, 08028 Barcelona, Catalonia, Spain;2. Murcia Fire Service, Spain |
| Abstract: | The current study estimates the radiation flux emitted from hot extended gas clouds characteristic of vapour cloud explosions along with the corresponding level of irradiance posed on particles suspended in the unburnt part of the cloud ahead of an advancing flame front. The data presented permits an assessment of the plausibility of combustion initiation by such particles due to forward thermal radiation. The thermal radiation will depend on the emissivity of the burned volume, which relates to the concentration of gaseous and particulate combustion products. A sensitivity analysis has been carried out to account for variations in the equivalence ratio, mixture pressure and radiative heat losses. The spatial distribution of irradiance ahead of the flame front has been computed by introducing appropriate geometrical factors to explore the impact of cloud size. Using fuel rich ethylene-air mixtures it has been shown that high flame emissivities can be achieved at path lengths of order 1 m even in the presence of very low soot volume fractions. The emissivity of gas-soot mixtures will hence be mainly determined by the soot concentration and to a lesser extent by the mixture temperature. Our analysis suggests that the role of forward thermal radiation as a contributing factor to flame propagation in large scale vapour cloud explosions can not currently be ruled out. |
| Keywords: | Radiation induced ignition Vapour cloud explosions Soot Cloud size effects Temperature effects Impact of mixture composition |
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