Numerical Modelling of the Fire Extinguishing Gas Retention in Small Compartments

Boroń, Sylwia; Węgrzyński, Wojciech; Kubica, Przemysław; Czarnecki, Lech

doi:10.3390/app9040663

Cited by 13 publications

(18 citation statements)

References 38 publications

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“…This solver has been widely used in fire research analyses and is recognized by some of the smoke control standards [26]. Some validation examples for ANSYS Fluent were given in [27][28][29][30][31]. The principal assumptions for numerical calculations and the choice of physical sub-models are summarized in Table 1.…”

Section: Case Study-numerical Modelmentioning

confidence: 99%

3D Mapping of the Sprinkler Activation Time

et al. 2020

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Sprinkler activation is one of the key events defining the course of a compartment fire. The time when activation occurs is commonly used in the determination of the design fire scenario, which is the cornerstone of the design of building fire safety features. A well-known model of sprinkler activation (response time index (RTI) model) was introduced into the numerical scheme of the ANSYS Fluent computational fluid dynamics (CFD) package. The novel way in which the model is used is the calculation of the time for sprinkler activation within each discrete cell of the domain. The proposed novel approach was used in a case-study to assess the effects of comfort mode natural ventilation on a sprinkler’s activation pattern. It was found that hinged vents in the comfort mode had a significant effect on sprinkler activation, both in terms of delaying it as well as limiting the total number of cells in which the sprinkler would have activated. In some scenarios with a hinged vent, no activation was observed in the central point of the vent, possibly indicating problems with the autonomous triggering of the fire mode of such a device. It was also found that the RTI and C (related to the conductive transport of sprinkler fitting) parameter values had a moderate influence on sprinkler activation time—only for high-temperature sprinklers (≥ 141 °C). This study shows the applicability of the 3D activation time mapping for research focused on the fire safety of sprinkler-protected compartments and for the performance-based approach to sprinkler system design. Even though the RTI model is the industry standard for the determination of sprinkler response, the model implementation in ANSYS Fluent was not validated. This means that sources of uncertainty, mainly connected with the determination of flow velocity and temperature are not known, and the model should be used with caution. An in-depth validation is planned for subsequent studies.

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Section: Case Study-numerical Modelmentioning

confidence: 99%

3D Mapping of the Sprinkler Activation Time

et al. 2020

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“…The fire spread to the 28th floor in less than 4 minutes with the help of stack effects; thus, the majority of people had no time to escape. Another significant case is that of the closed-circuit television (CCTV) Cultural Center Building fire, which led to 17 casualties and economic losses of 160 million yuan in 2009 [6].…”

Section: Introductionmentioning

confidence: 99%

“…For example, the MGM Grand fire occurred in 1980 in the United States and led to 85 fatalities, most of which were located on the upper floors, which were a distance away from the fire source, as the fatalities were due to toxic smoke. [3][4][5][6][7]. Furthermore, the stack effect intensifies flame propagation in high rise buildings, which results from the difference between the densities of the warm internal air and cold external air [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5][6][7]. Furthermore, the stack effect intensifies flame propagation in high rise buildings, which results from the difference between the densities of the warm internal air and cold external air [4][5][6][7][8][9]. In addition, the stack effect is more pronounced in vertical shaft structures with an increase in height, by which the thermal smoke moves more rapidly from the lower to upper floors.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on Smoke Flow in Stairwells induced by an Adjacent Compartment Fire in High Rise Buildings

et al. 2019

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The aim of this study was to evaluate the transport phenomena of smoke flow and vertical temperature distribution in a 21-story stairwell with multiple fire locations and openings. A large eddy simulation (LES) method was used to model the smoke flow in a stairwell model with a set of simulation parameters, wherein the fire heat release rate (HRR) and fire location were varied. Based on the results, a wall attachment effect was found in three-dimensional figures. Moreover, with an increase in the fire HRR, the effects were more pronounced. The simulation results verified that the vertical temperature distribution is an index model with a natural logarithm, where the pre-finger factor and attenuation coefficient increase considerably in accordance with an increase in the fire HRR. Moreover, there was a decrease in the maximum temperature (Tm) with an increase in the fire location factor (h*) due to the upward thermal smoke. Moreover, heat mainly accumulates in the area above a fire source. However, h* has a slight influence on the time required to reach Tm within the range of 53–64 s. Furthermore, the direction of the airflow at each side opening in the stairwell varied in accordance with the variation in the fire location changes, and a regular calculation was carried out.

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“…To simulate compartment fires, the computational codes used include Fire Dynamics Simulator (FDS), FireFOAM, OpenFOAM, PHOENICS, FLUENT and CFX, among others (see, e.g., [7,10,[12][13][14][15][16][17]). All these codes have been extensively validated for a great variety of fire scenarios in the case of the first two and for a very large number of applications in the field of fluid mechanics in the case of the others.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Heat and Smoke Propagation and Oscillatory Flow through Ceiling Vents in a Large-Scale Compartment Fire

et al. 2019

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One question that often arises is whether a specialized code or a more general code may be equally suitable for fire modeling. This paper investigates the performance and capabilities of a specialized code (FDS) and a general-purpose code (FLUENT) to simulate a fire in the commercial area of an underground intermodal transportation station. In order to facilitate a more precise comparison between the two codes, especially with regard to ventilation issues, the number of factors that may affect the fire evolution is reduced by simplifying the scenario and the fire model. The codes are applied to the same fire scenario using a simplified fire model, which considers a source of mass, heat and species to characterize the fire focus, and whose results are also compared with those obtained using FDS and a combustion model. An oscillating behavior of the fire-induced convective heat and mass fluxes through the natural vents is predicted, whose frequency compares well with experimental results for the ranges of compartment heights and heat release rates considered. The results obtained with the two codes for the smoke and heat propagation patterns and convective fluxes through the forced and natural ventilation systems are discussed and compared to each other. The agreement is very good for the temperature and species concentration distributions and the overall flow pattern, whereas appreciable discrepancies are only found in the oscillatory behavior of the fire-induced convective heat and mass fluxes through the natural vents. The relative performance of the codes in terms of central processing unit (CPU) time consumption is also discussed.

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Numerical Modelling of the Fire Extinguishing Gas Retention in Small Compartments

Cited by 13 publications

References 38 publications

3D Mapping of the Sprinkler Activation Time

3D Mapping of the Sprinkler Activation Time

Investigation on Smoke Flow in Stairwells induced by an Adjacent Compartment Fire in High Rise Buildings

Analysis of Heat and Smoke Propagation and Oscillatory Flow through Ceiling Vents in a Large-Scale Compartment Fire

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