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Development of a Methodology for Interface Boundary Selection in the Multiscale Road Tunnel Fire Simulations

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dc.contributor.authorHaghighat, Alirezaen
dc.contributor.authorLuxbacher, Kramer Davisen
dc.contributor.authorLattimer, Brian Y.en
dc.contributor.departmentMining and Minerals Engineeringen
dc.date.accessioned2019-09-05T17:12:01Zen
dc.date.available2019-09-05T17:12:01Zen
dc.date.issued2018-07en
dc.description.abstractThe simulation of large complex dynamical systems such as a fire in road tunnels is necessary but costly. Therefore, there is a crucial need to design efficient models. Coupling of computational fluid dynamics (CFD) models and 1D network modeling simulations of a fire event, a multiscale method, can be a useful tool to increase the computational efficiency while the accuracy of simulations is maintained. The boundary between a CFD model (near field) and a 1D model (far field) plays a key role in the accuracy of simulations of large systems. The research presented in this paper develops a novel methodology to select the interface boundary between the 3D CFD model and a 1D model in the multiscale simulation of vehicle fire events in a tunnel. The development of the methodology is based on the physics of the fluid structure, turbulent kinetic energy of the dynamical system, and the vortex dynamics. The methodology was applied to a tunnel with 73.73 m(2) cross section and 960 m in length. Three different vehicle fire scenarios were investigated based on two different heat reslease rates (10 MW and 30 MW) and two different inlet velocities (1.5 m/s and 5 m/s). all parameters upstream and downstream of the fire source in all scenarios were investigated at t = 900 s. The effect of changes in heat release rate (HRR) and air velocity on the selection of an interface boundary was investigated. The ratio between maximum longitudinal and transversal velocities was within a range of 10 to 20 in the quasi-1D region downstream of the fire source. The selected downstream interface boundary was 12D(h) m downstream of the fire for the simulations. The upstream interface boundary was selected at 0.5 D-h m upstream the tip of the object when the velocity was greater than equal to the V-c. In the simulations with backlayering (V < V-c), the interface boundary was selected 10 m further from the tip of the backlayering (1.2 D-h). An indirect coupling strategy was utilized to couple CFD models to 1D models at the selected interface boundary; then, the coupled models results were compared to the full CFD model results. The calculated error between CFD and coupled models for mean temperature and velocity at different cross sections were calculated at less than 5%. The findings were used to recommend a modification to the selection of interface boundary in multiscale fire simulations in the road tunnels and more complex geometries such as mines.en
dc.description.notesThis research was developed under Contract No. 200-2014-59669, awarded by the National Institute for Occupational Safety and Health (NIOSH). The findings and conclusions in this report are those of the authors and do not reflect the official policies of the Department of Health and Human Services; nor does mention of trade names, commercial practices, or organizations imply endorsement by the U.S. Government.en
dc.description.sponsorshipNational Institute for Occupational Safety and Health (NIOSH) [200-2014-59669]en
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1007/s10694-018-0724-0en
dc.identifier.eissn1572-8099en
dc.identifier.issn0015-2684en
dc.identifier.issue4en
dc.identifier.urihttp://hdl.handle.net/10919/93400en
dc.identifier.volume54en
dc.language.isoenen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectComputational fluid dynamics (CFD)en
dc.subjectInterface boundaryen
dc.subjectTransportation tunnel fireen
dc.subjectMultiscale methodologyen
dc.titleDevelopment of a Methodology for Interface Boundary Selection in the Multiscale Road Tunnel Fire Simulationsen
dc.title.serialFire Technologyen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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