Authors: Manhou Li Shouxiang Lu Jin Guo Ruiyu Chen KwokLeung Tsui
Publish Date: 2014/10/08
Volume: 119, Issue: 1, Pages: 401-409
Abstract
Comparative tests were conducted at normal Hefei city 50 m 100 kPa and elevated altitude Lhasa city 3650 m 64 kPa on flame spread over subflash nbutanol surface Flame height flame pulsation frequency flame spread rate and subsurface convection flow size and temperature are quantified to find out their behavioral changes for these two altitudes Results show that the flame is less luminous and lower soot production while the flame height and flame pulsation frequency are larger at the elevated altitude A theoretical deduction of fuel diffusion process based on Fick’s second law predicts that the flame pulsates more frequently at higher initial fuel temperature which accords well with experimental results The flame pulsation period can be well correlated with dimensionless initial fuel temperature by a semilogarithmic fit regardless of altitude In addition the flame propagates more rapidly in Lhasa so that the fire hazard of the fuel leakage accident at the elevated altitude is greater than the normal counterpart The variation trend of subsurface convection flow length is the inverse of initial fuel temperature at both altitudes For a given initial fuel temperature the subsurface convection flow temperature and size at the elevated altitude are smaller than those recorded at the normal altitude The present findings provide a significant supplement over previous knowledge concerning liquid flame spread behaviors
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