Abstract: This study aimed to investigate the impact of various combinations of positive pressure mobile fans (parallel, series, upper-lower-shaped, and V-shaped) on the effectiveness of smoke exhaust during building fires. By employing a combination of experimental measurement and numerical simulation using a large eddy simulation fire dynamics model, this research examines the application scenarios, smoke extraction efficiency, and necessary precautions associated with different combinations of fire smoke extraction. The results suggest that four different combinations of fans effectively achieve the desired airflow to cover the air inlet and increase indoor pressure. Specifically, when the fans are arranged in a V-shape, the air intake effect is superior compared to other configurations within the building. It should be noted that the proximity of the two air jets can lead to the formation of overlapping air cones between fans, particularly in the case of parallel-shaped and upper-lower-shaped fans. This overlapping can result in increased superposition of air vortices and energy consumption caused by certain air cones. This paper aims to examine the practical application of series-shaped positive pressure mobile fans, specifically addressing the issue of decreased flow rate caused by the obstruction of the rear airflow by the motor of the front fan. The objective is to verify the feasibility of employing this fan combination and establish a theoretical foundation for its use in smoke exhaust during fire incidents.

Key words: building fires, positive pressure mobile fan, fan combination, smoke extraction efficiency, FDS