Through a series of full-scale fire experiments and numerical simulations, the effectiveness of water mist system on wind generator could be estimated, and compared with fire parameters, such as exposed or unexposed fire sources, number of nozzles, un-sheltered or sheltered fire sources, and fire source location. The experimental study found that the position of the water mist nozzles and whether the flames inside the oil pan are covered have a significant influence on overall extinguishing efficacy. The water mist system proved to have sound effectiveness on fire suppression in wind generators with sheltered fire source. According to FDS simulations of water mist systems, the simulated temperature curve declined more significantly than that for the actual measurements, indicating that the cooling effect of the simulated water mist was better. However, simulations were used for a situation where water mist was unable to directly extinguish the fire. Analysis of the simulated airflow showed that an opening caused the water to discharge outwards and the airflow was disturbed by the outside; thus, the extinguishing effect was poorer. There was less water with a sheltering object, and thus the extinguishing effect was poorer. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.