Abstract: Considering little understanding about liquid nitrogen spray in fire prevention of data center,fire numerical simulation of a data center was carried out by FDS software. The variations of smoke spread, flame control, temperature distribution, visibility and other parameters were analyzed by comparing the two conditions, i.e., whether the liquid nitrogen fire extinguishing system exists or not. The results show that the liquid nitrogen spraying system has dispersive effect on controlling the fire smoke spreading and can improve the visibility in the corridor. Liquid nitrogen is vaporized and distributed rapidly in the whole space, and the temperature around the ignition point can be lowered to below 50 ℃ within 500 s to protect other equipment.Compared with traditional CO 2 extinguishing agent, liquid nitrogen fire extinguishing system has certain advantages.

Key words: computer data center, liquid nitrogen for firefighting and prevention;numerical simulation, temperature distribution;visibility