A Numerical Study of Window-to-Window Propagation in High-Rise Building Fires

This study describes numerical simulations of high-rise building fires extending to upward floors via windows. Flames and hot gases ejected from openings and flowing along vertical building exterior walls may fracture window glasses and accelerate the fire growth towards upper floors. Particularly, there have been no numerical studies of dynamic fire behavior around windows and along vertical exterior walls, in relation to the fire growth. Here is attempted numerical finite-difference studies of time-dependent flow behavior of fires along external building walls and of the behavior of fires invading into the upper floor windows. Two-dimensional numerical simulations show that upward flows adhere closely to the wall surface, similarly to the experimental flow patterns. Some large scale vortices are created around the upward fire gases. Almost periodically, "hot" gases enter the room immediately above the fire room via windows. The regular oscillatory motion depends upon the heat release rate in the fire room and is weakly ~ffected by the window configurations.