Justification of a Fire Model on Predicting Fire in Large Room

2012 ◽  
Vol 193-194 ◽  
pp. 1103-1108
Author(s):  
Shu Sheng Li ◽  
Ye Gao ◽  
Gao Wan Zou ◽  
Yan Huo
Keyword(s):  
Fire Test ◽  
Cfd Model ◽  
Layer Height ◽  
Fire Model ◽  
Fire Models ◽  
Air Temperatures ◽  
Fire Environment ◽  
Smoke Layer ◽  
Computational Fluid Dynamics Cfd ◽  
Microscopic Picture

Fire models using Computational Fluid Dynamics (CFD) are now popular design or evaluation tools as the computer’s development sharply. By those tools the thermal fire environment can be predicted in a ‘microscopic’ picture with air flow pattern, pressure and temperature contours. However, most of the fire models are only validated by some experiments not specially designed for such purpose, especially for large rooms. In this paper, an existing fire test was used to justify a fire model - FDS4.07 on predicting fires in large room. Smoke layer height and air temperatures inside the room were taken as the parameters. Functional analysis was applied to justify the predictions by the CFD model.

Justification of Fire Field Models by Atrium Hot Smoke Tests

2009 ◽  
Author(s):  
W. K. Chow ◽  
S. S. Li ◽  
C. L. Chow
Keyword(s):  
Field Model ◽  
Field Tests ◽  
Design Tool ◽  
Fire Dynamics ◽  
Design Fire ◽  
Air Temperatures ◽  
Fire Environment ◽  
Measurement Results ◽  
Smoke Layer ◽  
Computational Fluid Dynamics Cfd

Computer thermal fire models are used in hazard assessment for performance-based fire design. Fire field model using Computational Fluid Dynamics (CFD) is now a popular design tool. The thermal fire environment can be predicted in a ‘microscopic’ picture with air flow pattern, pressure and temperature contours. However, most of the field models are only validated by some experiments not specially designed for such purpose. Whether those models are suitable for use is queried, leading to challenges. In this paper, prediction on smoke filling in a big atrium by the CFD tool Fire Dynamics Simulator developed at the National Institute of Standards and Technology in USA was justified by field tests. Smoke layer interface height and air temperatures inside the atrium were taken as the parameters. CFD results predicted were compared with the field measurement results.

Cluster of High-Powered Racks Within a Raised-Floor Computer Data Center: Effect of Perforated Tile Flow Distribution on Rack Inlet Air Temperatures

2004 ◽  
Vol 126 (4) ◽  
pp. 510-518 ◽  
Author(s):  
Roger Schmidt ◽  
Ethan Cruz
Keyword(s):  
Data Center ◽  
Control Volume ◽  
Flow Distribution ◽  
Computer Code ◽  
Cfd Model ◽  
Computer Data ◽  
Air Temperatures ◽  
Finite Control ◽  
Computational Fluid Dynamics Cfd ◽  
Tile Flow

This paper focuses on the effect on rack inlet air temperatures as a result of maldistribution of airflows exiting the perforated tiles located adjacent to the fronts of the racks. The flow distribution exiting the perforated tiles was generated from a computational fluid dynamics (CFD) tool called Tileflow (trademark of Innovative Research, Inc.). Both raised floor heights and perforated tile-free areas were varied in order to explore the effect on rack inlet temperatures. The flow distribution exiting the perforated tiles was used as boundary conditions to the above-floor CFD model. A CFD model was generated for the room with electronic equipment installed on a raised floor. Forty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide×13.4 m long. Because the arrangement of the racks in the data center was symmetric, only half of the data center was modeled. The numerical modeling for the area above the raised floor was performed using a commercially available finite control volume computer code called Flotherm (trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.

Cluster of High Powered Racks Within a Raised Floor Computer Data Center: Effect of Perforated Tile Flow Distribution on Rack Inlet Air Temperatures

2003 ◽  
Author(s):  
Roger Schmidt ◽  
Ethan Cruz
Keyword(s):  
Data Center ◽  
Control Volume ◽  
Flow Distribution ◽  
Computer Code ◽  
Cfd Model ◽  
Computer Data ◽  
Air Temperatures ◽  
Finite Control ◽  
Computational Fluid Dynamics Cfd ◽  
Tile Flow

This paper focuses on the effect on inlet rack air temperatures as a result of maldistribution of airflows exiting the perforated tiles located adjacent to the fronts of the racks. The flow distribution exiting the perforated tiles was generated from a computational fluid dynamics (CFD) tool called Tileflow (Trademark of Innovative Research, Inc.). Both raised floor heights and perforated tile free area were varied in order to explore the effect on rack inlet temperatures. The flow distribution exiting the perforated tiles was used as boundary conditions to the above floor CFD model. A CFD model was generated for the room with electronic equipment installed on a raised floor. Fourty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide × 13.4 m long. Since the arrangement of the racks in the data center was symmetric only one-half of the data center was modeled. The numerical modeling for above the raised floor was performed using a commercially available finite control volume computer code called Flotherm (Trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.

Time Domain Analysis of the Temperatures in an Electrical Auxiliary Building Room

2009 ◽  
Author(s):  
Andron Creary ◽  
Matthew F. King ◽  
Matthew Langston ◽  
Cable Kurwitz ◽  
Paul Nelson ◽  
...  
Keyword(s):  
Air Temperature ◽  
Model Experiment ◽  
Time Domain Analysis ◽  
Lumped Parameter Model ◽  
Scale Model ◽  
Small Scale ◽  
Cfd Model ◽  
Air Temperatures ◽  
Lumped Parameter ◽  
Computational Fluid Dynamics Cfd

A computational fluid dynamics (CFD) model has been developed to predict air temperatures within the switchgear room environment of a nuclear plant’s Electronics Auxiliary Building (EAB). In order to validate the CFD model output, a scale model experiment has been developed using an analytical model to properly scale important EAB room parameters to allow small scale experiments to be performed for validation of the CFD model. The focus of this paper is the development of the methodology used to accurately predict the bulk air temperature or the EAB room. The CFD model is compared to a simple lumped parameter model as well as a scale model experiment. The scaling approach matches the eigenvalues of the lumped parameter model. An experiment based on this scaling approach was performed and compared with CFD output. The time predicted by the CFD model of the Electrical Auxiliary Building room for the average air temperature to increase from 17.7 °C (64 °F) to 40 °C (104 °F) is 23.5 minutes. The lumped parameter analytic solution produces a mean time of 22 minutes. The heat up time for the experiment matches the CFD model providing confidence in the fidelity of the CFD model.

Assessment of Observational Environments of the Automated Synoptic Observing Systems in Korea Using a CFD Model

2020 ◽  
Author(s):  
Jung-Eun Kang ◽  
Jae-Jin Kim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Domain ◽  
Cfd Model ◽  
Meteorological Observation ◽  
Wind Speeds ◽  
Air Temperatures ◽  
Computational Fluid Dynamics Cfd ◽  
Meteorological Observations ◽  
Observing Systems

<p>  In this study, we analyzed the observation environments of the automated synoptic observing systems (ASOSs) using a computational fluid dynamics (CFD) model, focusing on the observational environments of air temperatures, wind speeds, and wind directions. The computational domain sizes are 2000 m × 2000 m × 750 m, and the grid sizes are 10 m × 10 m × 5 m in the x-, y-, and z- directions, respectively. We conducted the simulations for eight inflow directions (northerly, northeasterly, easterly, southeasterly, southerly, southwesterly, westerly, northwesterly) using the ASOS-observation wind speeds and air temperatures averaged in August from 2010 to 2019. We analyzed the effects of the surrounding buildings and terrains on the meteorological observations of the ASOSs, by comparing the wind speeds, wind directions, and air temperatures simulated at the ASOSs with those of inflows. The results showed that the meteorological observation environments were quite dependent on whether there existed the obstacles and surface heating on their surfaces at the observation altitude of the ASOSs.</p>

Effects of Over Fire Air on the Combustion and NOx Emission Characteristics of a 600 MW Opposed Swirling Fired Boiler

2012 ◽  
Vol 512-515 ◽  
pp. 2135-2142 ◽  
Author(s):  
Yu Peng Wu ◽  
Zhi Yong Wen ◽  
Yue Liang Shen ◽  
Qing Yan Fang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Empirical Method ◽  
Nox Emission ◽  
Emission Characteristics ◽  
Cfd Model ◽  
Nitrogen Release ◽  
Computational Fluid Dynamics Cfd ◽  
Low Nox Emission

A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler

scholarly journals Event-Driven Simulations of Nonlinear Integrate-and-Fire Neurons

2007 ◽  
Vol 19 (12) ◽  
pp. 3226-3238 ◽  
Author(s):  
Arnaud Tonnelier ◽  
Hana Belmabrouk ◽  
Dominique Martinez
Keyword(s):  
Neural Networks ◽  
Spiking Neural Networks ◽  
Synaptic Currents ◽  
Fire Model ◽  
Integrate And Fire ◽  
Fire Models ◽  
Event Driven

Event-driven strategies have been used to simulate spiking neural networks exactly. Previous work is limited to linear integrate-and-fire neurons. In this note, we extend event-driven schemes to a class of nonlinear integrate-and-fire models. Results are presented for the quadratic integrate-and-fire model with instantaneous or exponential synaptic currents. Extensions to conductance-based currents and exponential integrate-and-fire neurons are discussed.

Validation of a Computationally Efficient Computational Fluid Dynamics (CFD) Model for Industrial Bubble Column Bioreactors

2014 ◽  
Vol 53 (37) ◽  
pp. 14526-14543 ◽  
Author(s):  
Dale D. McClure ◽  
Hannah Norris ◽  
John M. Kavanagh ◽  
David F. Fletcher ◽  
Geoffrey W. Barton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Bubble Column ◽  
Cfd Model ◽  
Computationally Efficient ◽  
Computational Fluid Dynamics Cfd

An Integrated Ship Re-Design/Modification Strategy

2019 ◽  
Vol 161 (A1) ◽  
Keyword(s):  
Computer Aided Design ◽  
Modular Design ◽  
Ship Hull ◽  
Cfd Model ◽  
Hull Form ◽  
Design Modification ◽  
Technical Parameters ◽  
Computational Fluid Dynamics Cfd ◽  
Bulbous Bow ◽  
Aided Design

Herein, we present an integrated ship re-design/modification strategy that integrates the ‘Computer-Aided Design (CAD)’ and ‘Computational Fluid Dynamics (CFD)’ to modify the ship hull form for better performance in resistance. We assume a modular design and the ship hull form modification focuses on the forward module (e.g. bulbous bow) and aft module (e.g. stern bulb) only. The ship hull form CAD model is implemented with NAPA*TM and CFD model is implemented with Shipflow**TM. The basic ship hull form parameters are not changed and the modifications in some of the technical parameters because of re-designed bulbous bow and stern bulb are kept at very minimum. The bulbous bow is re-designed by extending an earlier method (Sharma and Sha (2005b)) and stern bulb parameters for re-design are computed from the experience gained from literature survey. The re-designed hull form is modeled in CAD and is integrated and analyzed with Shipflow**TM. The CAD and CFD integrated model is validated and verified with the ITTC approved recommendations and guidelines. The proposed numerical methodology is implemented on the ship hull form modification of a benchmark ship, i.e. KRISO container ship (KCS). The presented results show that the modified ship hull form of KCS - with only bow and stern modifications - using the present strategy, results into resistance and propulsive improvement.

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