Flow Path Trajectory and Pressure Loss in a Water Monitor Design

摘要

To be effective, a fire fighting water monitor requires the maximum delivery of water onto the targeted fire source. Most commercial water monitors have a flow capacity of up to 2500 gallons per minute (GPM) and a diameter of four inches. To meet the market demand of even higher capacity flow rates, the design issues of a two degree of freedom six inch diameter water monitor with a flow capacity of 3000 GPM is investigated. To maximize the water flow rate in a designed system, the loss of water pressure in the monitor needs to be minimized. A computational fluid dynamics (CFD) tool is used to study the effect of flow path trajectory on the pressure, loss in a flow system. The flow path is defined by two radial arcs tangent to each other. For a set of the flow parameters and a given flow area, the loss of water pressure is computed. The correlation between pressure loss and path geometry is used to determine the optimal path radii. This paper presents the determination of optimal path radii of the flow system and corresponding system design. The designed system achieved a 34% improvement in pressure loss compared to standard commercial designs.