Large eddy simulation of thermal stratification effect on natural ventilation performance in a corridor fire with a ceiling-duct

Numerical simulations were carried out by using Large Eddy Simulation in a corridor fire with a ceiling-duct to investigate the smoke thermal stratification effect on natural ventilation performance. It was studied the influence of the geometric duct variations on the smoke layer stability based on the stratification parameter and the flow field behavior in the corridor. Results show that the mixing effect and the plug-holing increase with the duct section and the duct height increasing. The strong vertical inertial force could break the stratification stability, and thus the smoke layer descends to near ground resulting in poor natural ventilation performance. The modified parameter showed that the stratification becomes unstable in case of $$S_{mod} { } \le 1.1$$ and a new correlation is predicted for the design of the smoke layer stratification.