Abstract: In view of the problem that mobile fire smoke exhaust fans generally adopt the positive pressure air supply and smoke exhaust mode, and the existing in-duct air volume testing methods cannot objectively reflect their ductless air supply characteristics, this paper focuses on the air supply characteristics and influencing factors of new high-efficiency and large-air-volume mobile fire smoke exhaust fans, and establishes an air volume testing method suitable for ductless conditions. Based on 4 new high-efficiency and large-air-volume mobile fire smoke exhaust fans, the paper designs 5 typical working conditions and completes the actual measurement of wind speed and air volume. The test results show that the wind speed attenuates outward from the axis in a volcano-like distribution, while the air volume reaches the maximum at a specific annular radius, and the distribution laws of the two are inconsistent. In terms of the influencing factors of air supply characteristics, the fan power has the most significant impact on air volume output, followed by the impeller diameter, while the number of blades and test distance have relatively smaller impacts.

Key words: mobile fire fan, air volume testing, impeller diameter, air supply characteristics