On the ability of twin jets air curtains to confine heat and mass inside tunnels

The ability of DS-TJ curtains to confine heat inside tunnels is studied both numerically and experimentally. The Fire Dynamics Simulator (FDS) code was used to perform 3D numerical simulations, while temperature and velocity measurements were obtained by fine thermocouples and Laser Doppler Velocimetry (LDV), respectively. Mean velocity and temperature profiles from simulations were compared with experimental data. Two cases are considered: a first case with Re = 1000 for the twin jets, and a second case where the exit velocity of both jets is the same (3 m/s). A confinement coefficient was proposed to compare both cases, revealing that the first case is more effective in avoiding heat leakage. The instabilities in the mixing layers and the flow structure in the impinging region are responsible for the heat and mass transfer through the DS-TJ.