Experimental study on the effect of makeup air inlets height on the fire combustion and smoke diffusion

Abstract

The position of makeup air inlets has significant impacts on fire combustion and the smoke spread characteristics. Therefore, influences of makeup air inlets located at different heights on fire combustion and smoke diffusion were discussed through experiments. Experimental results show that when the air inlet was 0.3 m above the ground, the flame width was the largest and the heat release rate (HRR) was the highest. When the height of air inlets was 2.3 m, both the heights of fire flame and smoke layer were the highest. The heights of air inlets were 0.3, 1.3, 2.3 and 3.3 m, the corresponding HRR of the fire was 1.12, 1.06, 0.87 and 0.81 times that of the HRR of the fire natural combustion. There is a logarithmic function relationship between the air inlets height and the HRR, and a polynomial function relationship between the flame height and the air inlets height. When the air inlets was installed at 3.3 m above the ground, the smoke layer height was the lowest, only approximately 1.0 m. Therefore, for rooms with similar dimensions, the makeup air inlets are recommended installed at 1.3–2.3 m above the ground.

Keywords

• Makeup air inlet height
• Flame
• Heat release rate (HRR)
• Smoke layer height
• Temperature
• Fire