With water mist regarded as a promising fireextinguishing agent in spacecraft,it is necessary to investigate characteristics of water mist in microgravity.In this paper,FDS 6.0 is used to measure the centerline velocity of water mist with various initial velocities and the spray distance.The droplets will approach their terminal velocity after leaving the nozzle in normal-gravity,which agrees with the theoretical calculation.The velocity of water mist declines in microgravity.The polynomials of the velocity change are given in microgravity,which makes it possible to obtain the velocity with the spray distance increase when arbitrary initial velocity is given.
