Effect of different air settings over fire-induced condition in a stairwell

2017 ◽  
Vol 8 (4) ◽  
pp. 440-458
Author(s):  
Aristides Lopes da Silva ◽  
Shengwu Xiong ◽  
Hussain Aamir
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Methodology ◽  
Numerical Study ◽  
Air Velocity ◽  
Fire Dynamics ◽  
Content Type ◽  
Fire Dynamics Simulator ◽  
Air Inlet ◽  
Transient Measurements

Purpose This work aims to report the effect of different inlet air velocity settings, and the position of the inlet areas under fire-induced conditions in stairwells. Design/methodology/approach The results are evaluated both experimentally and numerically. In sequence, the study also describes the results of three tests under different ventilation conditions, which were performed by simulating a fire of 0.9 m diameter in a stairwell access door. Detailed transient measurements of air temperature in the walls, air velocity settings at the ventilation outlet, smoke temperature through the fans and pressure through the exhaust fans were recorded for the study. Findings These data could be used as benchmark for future numerical validation studies. Based on computational fluid dynamics, the tests were performed using fire dynamics simulator codes, to compare the results of tests and simulations. Originality/value The numerical study was performed in confined floors close to the test areas of a typical stairwell, with different vents and a source of fire. The results show that the lack of symmetry in the air vents settings has greater influence on the plume than the total area of the air inlet.

Numerical Study on the Outdoor Wind Effects on Movement Smoke along a Corridor

2020 ◽  
Author(s):  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Quentin Serra ◽  
Aijuan Wang ◽  
Eric Florentin
Keyword(s):  
Fluid Dynamics ◽  
Input Data ◽  
Numerical Study ◽  
Numerical Data ◽  
Experimental Result ◽  
Fire Dynamics ◽  
Entire Volume ◽  
Global Sensitivity ◽  
Fire Dynamics Simulator ◽  
Computational Fluid Dynamics Cfd

In this chapter, a numerical investigation is presented in order to highlight the effects of outdoor wind on smoke movements along a corridor in a compartment. For this, the Computational Fluid Dynamics (CFD) code, fire dynamics simulator (FDS), was used to model the reactive flows in interaction with outdoor wind. The wind velocity is taken between 0 and 12.12 m/s, based on the experimental result data come from the work of Li et al. was performed. From numerical data, it was found that smoke stratification state in the corridor depends on Froude number (Fr) and it can be divided into three cases: stable buoyant stratification (Fr < 0.38), unstable buoyant stratification (0.38 ≤ Fr < 0.76), and failed stratification (Fr ≥ 0.76). When Fr ≥ 0.76, smoke stratification is completely disturbed and smoke occupies the entire volume of the compartment, highlighting a risk of toxicity to people. Indeed, it was observed that the velocity of the outdoor wind influences strongly the concentration of O2, CO2, CO, and visibility in the corridor and smoke exhaust. Moreover, for the input data used in the numerical modelling, the global sensitivity analysis demonstrated that the main parameters affecting the smoke temperature near the ceiling are the mass flux of fuel and the activation energy.

Modelling the effect of computation sampling on insight error in computational fluid dynamics scientific simulation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Moeti Masiane ◽  
Eric Jacques ◽  
Wuchun Feng ◽  
Chris North
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Methodology ◽  
Cfd Simulation ◽  
Grid Resolution ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Independent Variable ◽  
Cfd Applications ◽  
The Ideal

Purpose The purpose of this paper is to collect data from humans as they generate insights from the visualised results of computational fluid dynamics (CFD) scientific simulation. The authors hypothesise the behaviour of their insight errors (IEs) and proceed to quantify the IEs provided by the crowd participants. They then use the insight framework to model the behaviours of the errors. Using the crowd responses and models from the framework, they test the hypotheses and use the results to validate the framework for the speedup of CFD applications. Design/methodology/approach The authors use a randomised between-subjects experiment with blocking. CFD grid resolution is the independent variable while IE is the dependent variable. The experiment has one treatment factor with five levels. In case varying timestamps has an effect on insight variance levels, the authors block the responses by timestep. In total, 150 participants are randomly assigned to one of five groups and also randomly assigned to one of five blocks within a treatment. Participants are asked to complete a benchmark and open-ended task. Findings The authors find that the variances of insight and perception errors have a U-shaped relationship with grid resolution, that similar to the previously studied visualisation applications, the IE framework is valid for insights generated from CFD results and grid resolution can be used to predict the variance of IE resulting from observing CFD post-processing results. Originality/value To the best of the authors’ knowledge, no other work has measured IE variance to present it to simulation users so that they can use it as a feedback metric for selecting the ideal grid resolution when using grid resolution to speedup CFD simulation.

An evaluation of fire-plume properties simulated with the Fire Dynamics Simulator (FDS) and the Clark coupled wildfire model

2006 ◽  
Vol 36 (11) ◽  
pp. 2894-2908 ◽  
Author(s):  
Ruiyu Sun ◽  
Mary Ann Jenkins ◽  
Steven K Krueger ◽  
William Mell ◽  
Joseph J Charney
Keyword(s):  
Fluid Dynamics ◽  
Data Sets ◽  
Fire Plume ◽  
Fire Dynamics ◽  
Fire Model ◽  
Fire Dynamics Simulator ◽  
Physically Based ◽  
Vertical Grid ◽  
Simplifying Assumptions ◽  
Good Agreement

Before using a fluid dynamics physically based wildfire model to study wildfire, validation is necessary and model results need to be systematically and objectively analyzed and compared to real fires, which requires suitable data sets. Observational data from the Meteotron experiment are used to evaluate the fire-plume properties simulated by two fluid dynamics numerical wildfire models, the Fire Dynamics Simulator (FDS) and the Clark coupled atmosphere–fire model. Comparisons based on classical plume theory between numerical model and experimental Meteotron results show that plume theory, because of its simplifying assumptions, is a fair but restricted rendition of important plume-averaged properties. The study indicates that the FDS, an explicit and computationally demanding model, produces good agreement with the Meteotron results even at a relatively coarse horizontal grid size of 4 m for the FDS, while the coupled atmosphere–fire model, a less explicit and less computationally demanding model, can produce good agreement, but that the agreement is sensitive to surface vertical-grid sizes and the method by which the energy released from the fire is put into the atmosphere.

Cooling and Freezing of Cashew Apple Using Computational Fluid Dynamics

2020 ◽  
Vol 25 ◽  
pp. 114-132 ◽  
Author(s):  
V.A. Agra Brandão ◽  
R. Araújo de Queiroz ◽  
R. Lima Dantas ◽  
G. Santos de Lima ◽  
N. Lima Tresena ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nutritional Value ◽  
Fruits And Vegetables ◽  
Numerical Study ◽  
Freezing Process ◽  
Ansys Cfx ◽  
Cashew Apple ◽  
Freezing Period ◽  
Kinetics Of

Freezing is one the most efficient methods for conservation, especially, fruits and vegetables. Cashew is a fruit with high nutritional value and great economic importance in the Northeast region of Brazil, however, due to high moisture content, it is highly perishable. The numerical study of the freezing process is of great importance for the optimization of the process. In this sense, the objective of this work was to study the cooling and freezing processes of cashew apple using computational fluid dynamics technique. Experiments of cooling and freezing of the fruit, with the aid of a refrigerator,data acquisition system and thermocouples, and simulation using Ansys CFX® software for obtain the cooling and freezing kinetics of the product were realized. Results of the cooling and freezing kinetics of the cashew apple and temperature distribution inside the cashew apple are presented, compared and analyzed. The model was able to predict temperaturetransient behavior with good accuracy, except in the post-freezing period.

Numerical study of the biomass pyrolysis process in a spouted bed reactor through computational fluid dynamics

Energy ◽  
2021 ◽  
Vol 214 ◽  
pp. 118839
Author(s):  
Shiliang Yang ◽  
Ruihan Dong ◽  
Yanxiang Du ◽  
Shuai Wang ◽  
Hua Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Study ◽  
Pyrolysis Process ◽  
Biomass Pyrolysis ◽  
Spouted Bed

Airflow Simulation of the Huge Telescope Assemble

2010 ◽  
Vol 439-440 ◽  
pp. 880-883
Author(s):  
Fu Zhao ◽  
Ping Wang ◽  
Yan Jue Gong ◽  
Yu De Liu ◽  
Hong Bin Xin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Convection ◽  
Temperature Distribution ◽  
Velocity Field ◽  
Three Dimensional ◽  
Horizontal Line ◽  
Air Velocity ◽  
Turbulent Airflow ◽  
Dynamics Method

With the three-dimensional computational fluid dynamics method, the airflow effects over the huge telescope assemble is investigated in this article. The distributing of velocity field and natural convection are studied by modeling and simulating the turbulent airflow of the huge telescope. Numerical simulations show the best observation direction is the 90o angle between the main optics axis and the horizontal line in which the air velocity distribution is the least. And the air temperature distribution and uniformity around the telescope are also provided by simulation.

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