Topology optimization for design of a water monitor

Abstract

For a given firefighting pump, delivery of maximum amount of water often determines effectiveness of the overall system. In typical commercial water monitor, about 10% of water pressure is lost due to friction in the flow path of water monitor. With proper analysis of the flow system and shape geometry, this pressure loss can be minimized significantly. This would allow fire fighters to pump more water in a shorter period, and in turn, save life and property. A typical commercial water monitors has a diameter of four inches and delivers 2,500 gallons per minute (GPM) of water at 100 psi pressure. In this paper, design analysis of pressure loss and shape optimization of a larger water monitor is presented. The monitor has a diameter of six inches and would deliver 3.000 GPM water at 100 psi pressure. Two path radii define the shape of the water monitor and its size is constrained by a rectangular prism of given dimensions. Based on a pressure loss cost function, a commercially available Computational Fluid Dynamics (CFD) tool is used to optimize the geometry of the flow path. Shape of its cross section is optimized by utilizing derivative of the cost function with respect to cross sectional area of the water monitor. Resulting system improved pressure loss by more than 46% compared to circular cross sectional flow path in standard design of a commercial system.