Impact of fire source characteristics and wall heat losses on smoke behaviour in a longitudinally ventilated reduced scale model tunnel: experiments and numerical simulations

摘要

Experiments were carried out on a laboratory scale model of a longitudinally ventilated tunnel, using a hot air jet to model the the source. The influence of the source characteristics, especially the balance between buoyancy and momentum, on the backlayering length was investigated. The experiments were also simulated by CFD, which allowed to quantify and control the heat losses. The combined experimental and numerical results indicate the relative importance of buoyancy as a driving force of the backlayer.