TY - JOUR
T1 - Effect of finite dimension on downward flame spread over PMMA slabs
T2 - Experimental and theoretical study
AU - Gong, Junhui
AU - Zhou, Xiaodong
AU - Li, Jing
AU - Yang, Lizhong
N1 - Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2015/8/11
Y1 - 2015/8/11
N2 - Abstract This work investigates experimentally and theoretically the heat and mass transfer process of downward flame spread over finite width polymethyl methacrylate (PMMA) slabs in quiescent air. A series of experiments with different sample dimensions, 3, 4, 5 and 6 mm thick and 1.5-12 cm wide, are conducted and a solid phase flame spread model is developed to predict the behaviors during the process. Being different from the 2-D condition, an inverse 'V' shape leading edge, accelerated mass loss rate and spread rate exist due to the lateral combustion of samples and enhanced oxygen diffusion. The angle of leading edge increases with increasing width for 3 mm slabs, whereas no significant change occurs for thicker samples. The analytical model indicates that the mass loss rate and spread rate are functions of thermal parameters, leading edge angle and geometry of material. For fixed thickness, a linear relationship exists between the mass loss rate and width, while the spread rate is inversely proportional to the width of sample. The model also supplies two methods to estimate the heat flux ahead of leading edge and on the pyrolysis surface: by measured mass loss rate or flame spread rate. The validity of the proposed model is verified by the good agreement between the experimental and predicted results.
AB - Abstract This work investigates experimentally and theoretically the heat and mass transfer process of downward flame spread over finite width polymethyl methacrylate (PMMA) slabs in quiescent air. A series of experiments with different sample dimensions, 3, 4, 5 and 6 mm thick and 1.5-12 cm wide, are conducted and a solid phase flame spread model is developed to predict the behaviors during the process. Being different from the 2-D condition, an inverse 'V' shape leading edge, accelerated mass loss rate and spread rate exist due to the lateral combustion of samples and enhanced oxygen diffusion. The angle of leading edge increases with increasing width for 3 mm slabs, whereas no significant change occurs for thicker samples. The analytical model indicates that the mass loss rate and spread rate are functions of thermal parameters, leading edge angle and geometry of material. For fixed thickness, a linear relationship exists between the mass loss rate and width, while the spread rate is inversely proportional to the width of sample. The model also supplies two methods to estimate the heat flux ahead of leading edge and on the pyrolysis surface: by measured mass loss rate or flame spread rate. The validity of the proposed model is verified by the good agreement between the experimental and predicted results.
KW - Combustion
KW - Downward flame spread
KW - Finite dimensions
KW - PMMA
UR - http://www.scopus.com/inward/record.url?scp=84938942560&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatmasstransfer.2015.07.091
DO - 10.1016/j.ijheatmasstransfer.2015.07.091
M3 - 文章
AN - SCOPUS:84938942560
SN - 0017-9310
VL - 91
SP - 225
EP - 234
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
M1 - 12306
ER -