Fire Protection Engineering Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2772
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Item VERIFICATION TESTS OF MASS CONSERVATION FOR FIREFOAM AND DEVELOPMENT OF A USER'S GUIDE(2019) Wu, Shiyun; Trouvé, Arnaud; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The objective of this study is to develop basic verification tests for FireFOAM, a large eddy simulation (LES) solver developed by FM Global for fire applications, and based on the general-purpose Computational Fluid Dynamics (CFD) solver called OpenFOAM. These tests will be eventually included in an upcoming User Guide for FireFOAM users. We focus here on a series of tests developed to evaluate global species mass conservation statements. The series includes a two-dimensional helium plume case, a three-dimensional helium plume case and a three-dimensional pool fire case. The two-dimensional helium plume case focuses on the effects of changing the temporal discretization scheme in FireFOAM. The three-dimensional helium plume case focuses on the effects of changing the spatial discretization scheme used to describe the convection terms in the governing equations. Finally, the three-dimensional pool fire case focuses on the effects of changing the number of outer loops used to provide coupling between the governing equations that are solved sequentially. The results of the tests provide valuable insight for FireFOAM users who need to make numerical choices on the temporal discretization scheme, the spatial discretization scheme and the number of outer loops with little guidance on the impact of these choices.Item A Methodology for Determining the Fire Performance Equivalency Amongst Similar Materials During a Full-scale Fire Scenario Based on Bench-scale Testing(2015) Lannon, Chad Michael; Stoliarov, Stanislav I; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A methodology was developed for determining the equivalency amongst materials during a full-scale fire scenario. This procedure utilizes milligram-scale and or bench-scale tests to obtain the effective physical and chemical properties of individual materials through an optimization procedure. A flame heat feedback model was developed for corner-wall flame spread and implemented into a two-dimensional pyrolysis model, ThermaKin2D. ThermaKin2D was utilized to simulate upward flame spread during the room corner test. A criterion was created that determines the fire performance of similar materials during this full-scale fire scenario and compares how each material performed relative to one another. A fire investigator will be able to better select materials for their reconstructive fire test based on the modeled full-scale fire performance of candidate materials compared to the exemplar material found during the fire investigation. Overall, this procedure is expected to improve a fire investigator’s ability to perform accurate reconstructive fire tests.Item An Integrated Methodology for Assessing Fire Simulation Code Uncertainty(2010) Ontiveros, Victor Luis; Milke, James A.; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Fire simulation codes are powerful tools for use in risk-informed and performance-based approaches for risk assessment. Given increasing use of fire simulation code results, accounting for the uncertainty inherent in fire simulation codes is becoming more important than ever. This research presents a "white-box" methodology with the goal of accounting for uncertainties resulting from simulation code. Uncertainties associated with the input variables used in the codes as well as the uncertainties associated with the sub-models and correlations used inside the simulation code are accounted for. A Bayesian estimation approach is used to integrate all evidence available and arrive at an estimate of the uncertainties associated with a parameter of interest being estimated by the simulation code. Two example applications of this methodology are presented.Item Smoke Characterization of Incipient Fire Sources for FDS Modeling(2008-08-29) Brookman, Matthew James; Mowrer, Frederick; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis describes the experimental and analytical methods used to characterize the heat and smoke release rates of eight different incipient fire sources. These characterizations are part of a larger effort to evaluate the current smoke detection prediction capabilities of the Fire Dynamics Simulator (FDS) version 5.1.0. FDS is a computational fluid dynamics model of fire development based on the concept of large eddy simulation; the FDS model is under ongoing development at the Building and Fire Research Laboratory of the National Institute of Standards and Technology. The experimental aspect of this thesis includes developing a repeatable test protocol and characterizing each of the fuel sources. The experimental data produced from this phase is then input into FDS and the results of these simulations are compared to these experimental data. FDS has provided a range of accuracy near 5 % of the input values for smoke characteristics. The lag times associated with the output data can largely be attributed to the uncorrected experimental data. The time scaled inputs for FDS are based on the time that the instrumentation within the exhaust duct detected the smoke release from the material and the transport time required to move the smoke from the specimen to the instrumentation is not compensated for. Some variations in detection and data acquisition are expected.