| description abstract | Abstract. Liquid nitrogen (LN2) has been proposed as an effective and environmentally benign fire extinguishing agent. Upon application of a fire, LN2 undergoes rapid evaporation and expansion that displaces oxygen and cools the fuel, thereby starving the combustion of oxygen and fuel. LN2 can be applied across a broad range of open fires, including those that are difficult to extinguish with conventional means such as water. This article presents the design, development, and testing of a laboratory-scale, remotely controlled unmanned ground vehicle (UGV) capable of transporting and dispensing LN2 onto a fire. This robotic vehicle can traverse rough terrains, while carrying an LN2 tank; it can then supply the cryogen to a targeted location through an insulated hose mounted on an articulated extending arm. Fire extinction experiments on an array of small fires of dried vegetation (longleaf pine needles) and pools of liquid fuels (alcohol and kerosene) demonstrated that this UGV can approach a fire to close proximity and deliver liquid cryogen inside the fire envelope through a hose/nozzle assembly, and expediently extinguish the fire. The results of this study show that such an LN2-carrying UGV may be used to assist firefighters in tackling challenging fires that are fast spreading and hard to access from a safe standoff distance, and in so doing protect critical infrastructure by enabling rapid and effective fire suppression. | |
