Abstract: The FDS software is used to simulate and study the coordinated exhaust effect of the jet fan and the mechanical exhaust system of an underground train maintenance warehouse. By analyzing the smoke diffusion velocity, the distribution characteristics of the smoke layer, the distribution of CO concentration and the smoke exhaust efficiency during the fire, the smoke exhaust effects of the jet fan in coordination with the mechanical smoke exhaust and the single mechanical smoke exhaust are compared and studied. Studies show that the jet fan in coordination with mechanical exhaust can effectively slow down the diffusion rate of smoke, and can reduce the thickness of the smoke layer in most areas of the warehouse, and increase the thickness of the local smoke layer at the exhaust port to improve the exhaust efficiency of the mechanical smoke exhaust system. Compared with the smoke exhaust efficiency in the single mechanical smoke exhaust condition, the most unfavorable smoke exhaust efficiency increased from 33.1% to 53.9%, and the best smoke exhaust efficiency also increased from 44.3% to 55.1%. In addition, under the condition of cooperating smoke exhaust with jet fans, for the CO deposition control and smoke exhaust efficiency in the warehouse, the effect is optimal when two sets of jet fans are turned on and the distance between the fan group near the fire source and the nearby smoke exhaust branch pipe is in the effective range of the fan. And as the angle of the downwardly inclined jet from the fan unit at the far end of the fire source gradually increases to an angle of 45° with the horizontal plane, the control effect of CO deposition and the smoke exhaust efficiency are improved.

Key words: underground maintenance warehouse, jet fan, mechanical smoke exhaust, synergistic smoke exhaust