Reduced Order Modeling for fire sprinkler sprays

Abstract

A Reduced Order Model (ROM) providing a highly detailed description of the sprinkler spray has been developed for engineering applications. The new ROM approach combines an elegantly parameterized analytical description of the dispersed spray with a tightly integrated high-fidelity description of the initial spray capable of producing a complete quantitative map of the entire sprinkler spray field from centerline to edge and ceiling to floor. The complex spray field is mapped using a sparsely sampled phase-space accounting for all drops produced by the sprinkler. The spray is mapped through fast two-dimensional trajectory calculations spanning this discretized phase-space to produce quantitative views of the spray in regions of interest or in its entirety. Spray patterns are easily extracted from this spray field according to attributes of interest. The ROM is demonstrated by comparing predicted and measured spray patterns generated below a commercial sprinkler. These spray patterns are quantified through spatial distributions of volume flux showing good agreement between measurements and ROM predictions (average error of 0.44 mm/min or 5% of peak volume flux). The speed and robustness of the ROM provide an unprecedented quantitative view of fire sprinkler spraying performance with sufficient accuracy for potential use in engineering design applications.