Modeling Smoke Visibility In CFD

Kang, Kai; MacDonald, H. M.

doi:10.3801/iafss.fss.8-1265

Cited by 9 publications

(4 citation statements)

References 11 publications

(25 reference statements)

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“…Building off of this body of work, Park and co-workers reported a peptide-catalyzed method for the enantioselective alkylation of aldehydes with dimethylzinc. 217 Their strategy was to optimize a dipeptide scaffold-without an N-terminal Schiff base-that is able to chelate to and activate dimethylzinc for addition to prochiral aldehydes, such as 5.8, providing access to enantioenriched secondary alcohols 5.9 (Figure 84). All of the peptides examined adhered to the general sequence R 2 -Xaa-Pro-OMe (5.10), in which the N-terminus was either monoor dialkylated.…”

Section: Organozinc Additions To Aldehydesmentioning

confidence: 99%

Asymmetric Catalysis Mediated by Synthetic Peptides, Version 2.0: Expansion of Scope and Mechanisms

et al. 2020

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Low molecular weight synthetic peptides have been demonstrated to be effective catalysts for an increasingly wide array of asymmetric transformations. In many cases, these peptide-based catalysts have enabled novel multifunctional substrate activation modes and unprecedented selectivity manifolds. These features, along with their ease of preparation, modular and tunable structures, and often biomimetic attributes make peptides well-suited as chiral catalysts, and of broad interest. Many examples of peptide-catalyzed asymmetric reactions have appeared in the literature since the last survey of this broad field in Chemical Reviews (Chem. Rev. 2007, 107, 5759-5812). The overarching goal of this new review is to provide a comprehensive account of the numerous advances in the field. As a corollary to this goal, we survey the many different types of catalytic reactions, ranging from acylation to C-C bond formation, in which peptides been successfully employed. In so doing, we devote significant discussion to the structural and mechanistic aspects of these reactions that are perhaps specific to peptide-based catalysts and their interactions with substrates and/or reagents.

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Section: Organozinc Additions To Aldehydesmentioning

confidence: 99%

Asymmetric Catalysis Mediated by Synthetic Peptides, Version 2.0: Expansion of Scope and Mechanisms

et al. 2020

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“…The distribution of smoke mass fraction is useful to confirm the estimated time of accessibility (Table 3) based on smoke visibility, despite that it is not directly equivalent to visibility [21]. For instance as marked as DL in Figure 4, the approximate area affected by smoke is qualitatively consistent with the estimated time of accessibility, that is, at t = 80 s, platform stairs P2-P5 are affected and at t = 240 s, smoke has reached P1 and P7 on the mezzanine.…”

Section: Tenability/accessibility Of Evacuation Pathsmentioning

confidence: 98%

“…Note that with respect to egress accessibility, this 50 ft (15 m) visibility is conservative, as it is stringent than that based on 30 ft (10 m). The smoke visibility is estimated based on ''line of sight'' for CFD [21] following the definition of the light extinction coefficient [17,22]. This method treats smoke visibility as an exponential attenuation over a path of view projection instead of using the correlation by Jin [23].…”

Section: Tenability/accessibility Of Evacuation Pathsmentioning

confidence: 99%

Application of Code Approach for Emergency Evacuation in a Rail Station

Kang

2007

Fire Technol

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This paper presents an emergency evacuation analysis during a mid-platform train fire in an underground rail station. A time-based evacuation scenario is developed taking into account the stairway inaccessibility due to smoke blockage. The calculation approach in NFPA 130 is then applied to a parametric study of this time-based scenario and its reliability is examined using a micro-simulation model. Both methods give consistent predictions of the exiting times. The results demonstrate that with the division of the station into two zones, the exiting time could not meet the code requirements, whereas it does meet the required exiting time without the division. Such division is due to smoke blockage and creates an uneven ratio of the occupant load to the available exiting capacity. This shows that appropriate consideration of the fire and smoke effects is important for station egress evaluation. Other issues such as the fire growth rate and the pre-evacuation time are also discussed.

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“…Smoke is assumed to have the effect of visual obscuration. The visibility toward the exit, or the distance that an occupant will be able to see from their location to the exit sign, is calculated using the method from Jin ( 10 ) and Kang and Macdonald ( 11 ), as shown in Equation 5.…”

Section: Literature Reviewmentioning

confidence: 99%

One-Way Coupling of Fire and Egress Modeling for Realistic Evaluation of Evacuation Process

Cheong

Majumdar

et al. 2021

Transportation Research Record: Journal of the Transportation R

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In the discipline of fire engineering, computational simulation tools are used to evaluate the available safe egress time (ASET) and required safe egress time (RSET) of a building fire. ASET and RSET are often analyzed separately, using computational fluid dynamics (CFD) and crowd dynamics, respectively. Although there are advantages to coupling the ASET and RSET analysis to quantify tenability conditions and reevaluate evacuation time within a building, the coupling process is computationally complex, requiring multiple steps. The coupling setup can be time-consuming, particularly when the results are limited to the modeled scenario. In addition, the procedure is not uniform throughout the industry. This paper presents the successful one-way coupling of CFD and crowd dynamics modeling through a new simplified methodology that captures the impact of fractional effective dose (FED) and reduced visibility from smoke on the individual evacuee’s movement and the human interaction. The simulation tools used were Fire Dynamics Simulator (FDS) and Oasys MassMotion for crowd dynamics. The coupling was carried out with the help of the software development kit of Oasys MassMotion in two different example geometries: an open-plan room and a floor with six rooms and a corridor. The results presented in this paper show that, when comparing an uncoupled and a coupled simulation, the effects of the smoke lead to different crowd density profiles, particularly closer to the exit, which elongates the overall evacuation time. This coupling method can be applied to any geometry because of its flexible and modular framework.

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Modeling Smoke Visibility In CFD

Cited by 9 publications

References 11 publications

Asymmetric Catalysis Mediated by Synthetic Peptides, Version 2.0: Expansion of Scope and Mechanisms

Asymmetric Catalysis Mediated by Synthetic Peptides, Version 2.0: Expansion of Scope and Mechanisms

Application of Code Approach for Emergency Evacuation in a Rail Station

One-Way Coupling of Fire and Egress Modeling for Realistic Evaluation of Evacuation Process

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