Numerical Study on the Effects of Smoke Vent Types and Opening Conditions on Compartment Fire Phenomena

In this study, numerical simulations were conducted to investigate the effects of various smoke vent types and opening conditions on compartment fire phenomena. The opening angles of the smoke vents were set to achieve an effective area of 1 m² for each smoke vent type (casement, top-hung, and bottom-hung), along with different opening widths (0.72, 1.44, and 2.16 m). The numerical simulation results indicated that installing the top-hung and bottom-hung types at the upper and lower parts of the opening, respectively, affected the outflow of high-temperature smoke and inflow of fresh air, respectively. Additionally, with the casement type, fresh air entered smoothly through the lower part of the opening, whereas high-temperature smoke was discharged through the upper part. The flow behaviors resulting from the smoke vent type and opening width (opening angle) significantly affected the temperature distribution in the compartment, height and temperature of the smoke layer, flow velocity distribution, mass flow rate through the opening, and flow coefficient. Under the tested numerical simulation conditions, the flow coefficients for opening widths of 0.72, 1.44, and 2.16 m were 0.60, 0.68, and 0.67 for the casement type; 0.59, 0.36, and 0.19 for the top-hung type; and 0.64, 0.59, and 0.54 for the bottom-hung type, respectively. Overall, the casement type exhibited a higher smoke layer height, lower smoke layer temperature, larger mass flow rate through the opening, and higher flow coefficient.