TY - JOUR
TI - Heat transfer on simplified pre-period stage of tunnel fire
AU - Liu Hungwei
AU - Yao Wei
JN - Thermal Science
PY - 2019
VL - 23
IS - 13
SP - 799
EP - 808
PT - Article
AB - Tunnel fire is a part of applied thermal problems. With increase of transient  temperature of the tunnel fire on the structure surface (i.e. tunnel  lining), the heat transfer from the surface is possibly varying transient  temperature distribution within the structure. The transient temperature  distribution is also possibly damaging the composition of structure  (micro-crack) because of critical damage temperature. Therefore, the  transient temperature distribution has a significantly important role on  defining mechanical and physical properties of structure and determining  thermal-induced damaged region. The damage at pre-period stage of tunnel  fire is perhaps more significant than that at the other period stages  because of thermal gradient. Consequently, a theoretical model was developed  for simplifying complicated thermal engineering during pre-period stage of  tunnel fire. A hollow solid model (HSM) in a combination of dimensional  analysis and heat transfer theory with Bessel’s Function and Duhamel’s  Theorem were employed to verify a theoretical equation for dimensionless  transient temperature distribution (DTTD) under linear transient thermal  loading (LTTL). Experimental and numerical methods were also adopted to  approve the results from this theoretical equation. The heating rate (M) is  a primary variable for discussing DTTD on three means. The heating rate of  10.191, 10 and 240°C/min were applied to experimental and numerical studies.  The experimental and numerical results are consistent with the theoretical  solution, successfully verifying that the theoretical solution can predict  the DTTD well in field. This equation can be used for thermal/tunnel  engineers to evaluate the damaged region and to obtain the parameters  related to DTTD.