Thesis entitled 'Analysis on the Fire Safety Aspects for Tunnels in Hong Kong with Mathematical Models' aims to study the fire and ventilation aspects related to tunnels. Consequent to a fire incident resulting from a truck carrying illegal diesel outside a tunnel in Lion Rock Tunnel in 1999; and a vehicle fire that occurred in Cross Harbour Tunnel in 2000, people in Hong Kong are quite concerned about the safety aspects of vehicular tunnels. The current regulations, codes, design guides, practices and safety requirements on fire and ventilation in tunnels are reviewed. A preliminary hazard assessment on spill fires with empirical expressions available in the literature and fire zone model was reported. The results and cooling jet expressions were applied to assess the probable tunnel environment.; Air flow induced by an accidental vehicular fire in a tunnel was simulated with a fire field model using the Computational Fluid Dynamics (CFD) package PHOENICS. Sensitivity analyses on the grid size and the number of iterations on the required computing time and accuracy of the results were carried out. Based on the results, simulations on different tunnel fire scenarios were presented. The parameters varied were the fire size, ventilation system and its capacity. Systems considered are longitudinal, semi-transverse, transverse, partial transverse, and combined longitudinal and semi-transverse ventilation systems. By applying the software, comparisons and engineering judgment were made between different types of tunnel ventilation systems on the basis of temperature distribution contours.; Moreover, whether CFD models are good enough to predict the temperature distribution patterns and flow in a confined enclosure was investigated by comparing with previously published data on room fire and tunnel fire tests. The important roles of longitudinal wind effect, radiation losses, heat release rate estimates and judgment in the selection of input data as well as the evaluation of the results of model runs have been demonstrated.; Fire safety management in the incidents is discussed and recommendations are made to the Authority for better fire safety management. For improving the outdoor air quality, the introduction of liquefied petroleum gas vehicles in Hong Kong bring about new safety impact and challenges.
展开▼
