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Fire suppression tests with ceiling sprinkler protection in a rack storage fuel configuration are simulated using a Computational Fluid Dynamics tool. The fuel is arranged in a double-row, six pallet-load wide and three-tier high (2×6×3) rack storage array. Each pallet load consists of three nested double-wall corrugated cardboard boxes surrounding a metal liner. Two types of ceiling sprinklers are used in this study: a pendent quick response sprinkler designated as K14, and an upright standard response sprinkler designated as K11.2. The tests are simulated using FireFOAM, which couples necessary sub-models for fire growth, sprinkler response, and fire suppression. Numerical results are compared with experiments for both free burn tests under a 20-MW calorimeter and sprinkler suppression tests under a 7.6 m high ceiling. For the free burn case, the model results show good quantitative agreement of heat release rates in all three phases, from ignition to fire growth and steady burning. For the suppression cases, the model reproduces the suppression effectiveness of the two sprinkler protection designs: K14 sprinklers suppress the fire rapidly with only one sprinkler activation, while with K11.2 sprinklers, both in the tests and simulation, the fire spreads to the pallets on the end of the fuel array with multiple sprinkler activations. The modeled sprinkler activation times are within the estimated experimental uncertainty following three repeat tests. Quantitative results characterizing sprinkler suppression performance obtained from the simulations, such as the actual delivered density (ADD) and water evaporation rate, are also reported.

A model for simulating thin liquid film transport over solid surfaces has been developed. The film transport for mass continuity and momentum were formulated as a two-dimensional set of equations using thin-film assumptions. These equations have been implemented in an open-source CFD code (OpenFOAM). Treatments for partial-wetting phenomena have been included in the model to account for the behavior near the contact-line. A surface-tangential force along the contact line has been developed to allow for the simulation of rivulets and dry patches in two-dimensional surface flow. An approach for applying contact angle effects to the model for a real stochastic surface is outlined. Additionally, experimental measurements were made for film flow over an inclined surface for a wide range of flow rates. Using these experimental results, the model has been validated for partially wetted flow over an inclined panel. The critical flow rate of a film over a given surface was used as validation for the model. Results show that for flow rates below the critical flow rate, the partially wetted behavior of the flow was reproduced. Comparisons to experimental flow patterns and wetted-area fractions were made.

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