Analysis of Fire Water Monitor Jet Reaction Forces and Their Influences on the Roll Stabilities of Urban Firefighting Vehicle

Urban main fire fighting vehicle is the most important item of firefighting equipment. The stability and safety of these vehicles need to be assured to avoid fire extinguishing accidents due to vehicle stability or safety problems, especially when firefighting under complex working conditions. Jet reaction force is produced by the stationary nozzle, and its direction is opposite of the jet direction. Consequently, the jet reaction force has a negative effect on the stability of the fire fighting vehicle during the firefighting process. Thus, this paper explores the relationship of jet reaction forces from a fire water monitor under different flow rate operating conditions by using finite element simulations (Fluent and Fluid-Structure Interaction simulations) and experimental research. The FSI method is proposed as a new simulation approach in this study to analyze the fire water monitor jet reaction force under different working conditions. Furthermore, the jet reaction forces are used to analyze the roll stability of urban firefighting vehicle by combining virtual prototype technology, which has not been studied in past publications. The firefighting vehicle rollover angle is 33.8\(^\circ\) when the fire water monitor is not in operation, and the angles decrease from 8.5% to 39.2% when the flow rate increases from 30 L/s to 120 L/s, respectively, compared with a flow rate equal to 0 L/s. Thus, these findings facilitate analyze of jet reaction forces under different flow rates to improve the safety performance of fire fighting vehicles.