scholarly journals Methods for Prediction of Temperature Distribution in Flashover Caused by Backdraft Fire

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Guowei Zhang ◽  
Guoqing Zhu ◽  
Guanglin Yuan ◽  
Lili Huang
Keyword(s):  
Temperature Distribution ◽  
Temperature Curve ◽  
Peak Temperature ◽  
Office Building ◽  
Temperature Peak ◽  
Experiment Data ◽  
Building Process ◽  
Fire Experiment ◽  
Fire Experiments ◽  
Peak Value

Accurately predicting temperature distribution in flashover fire is a key issue for evacuation and fire-fighting. Now many good flashover fire experiments have be conducted, but most of these experiments are proceeded in enclosure with fixed openings; researches on fire development and temperature distribution in flashover caused by backdraft fire did not receive enough attention. In order to study flashover phenomenon caused by backdraft fire, a full-scale fire experiment was conducted in one abandoned office building. Process of fire development and temperature distribution in room and corridor were separately recorded during the experiment. The experiment shows that fire development in enclosure is closely affected by the room ventilation. Unlike existing temperature curves which have only one temperature peak, temperature in flashover caused by backdraft may have more than one peak value and that there is a linear relationship between maximum peak temperature and distance away from fire compartment. Based on BFD curve and experimental data, mathematical models are proposed to predict temperature curve in flashover fire caused by backdraft at last. These conclusions and experiment data obtained in this paper could provide valuable reference to fire simulation, hazard assessment, and fire protection design.

scholarly journals Box Experiment Study of Thermally Enhanced SVE for Benzene

2021 ◽  
Vol 18 (8) ◽  
pp. 4062
Author(s):  
Qixiang Zhang ◽  
Qiyan Feng ◽  
Xueqiang Zhu ◽  
Mei Zhang ◽  
Yanjun Wang ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Concentration Distribution ◽  
Average Concentration ◽  
Soil Gas ◽  
Vapor Extraction ◽  
Operation Process ◽  
Repair Efficiency ◽  
Benzene Concentration ◽  
Benzene Content ◽  
Peak Value

In order to describe the changes of soil temperature field, air flow field and remediation situation with time during the process of thermally enhanced SVE (soil vapor extraction), a remediation experiment of benzene contaminated soil with single extraction pipe was carried out in a box device. The results showed that the whole temperature of the system was raised to 80 °C in 4 h. 43% of benzene were removed in the first 2% of the extraction time. After 24 h, the repair efficiency was close to 100%. The device can efficiently remove benzene from soil. By continuously monitoring the parameters in the operation process of the system, the spatial distribution of temperature and soil gas pollutant concentration with time was plotted. It showed the benzene concentration distribution in the soil gas was more consistent with the temperature distribution before the start of ventilation, and the concentration of benzene in the soil gas dropped rapidly after ventilation, while the temperature distribution was almost unaffected. In the treatment of soil with a benzene content of 17.8 mg∙kg−1, when the soil gas benzene concentration is the highest at 180 min, the peak value is 11,200 mg∙m−3, and the average concentration is 7629.4 mg∙m−3.

scholarly journals Peak Temperature Correlation and Temperature Distribution during Joining of AZ80A Mg Alloy by FSW – A Numerical and Experimental Investigation

2020 ◽  
Vol 66 (6) ◽  
pp. 395-407 ◽  
Author(s):  
p Sevvel ◽  
S.D. Dhanesh Babu ◽  
R. Senthil Kumar
Keyword(s):  
Experimental Investigation ◽  
Temperature Distribution ◽  
Quadratic Equation ◽  
Peak Temperature ◽  
Mg Alloy ◽  
Element Analysis ◽  
Temperature Correlation ◽  
Friction Stir ◽  
Az80a Mg Alloy ◽  
Experimental Values

A quadratic equation has been developed based on experimental measurements to estimate the peak temperature in the friction stir welding (FSW) process during the joining of AZ80A Mg alloys. The numerical simulation of the FSW process was performed by employing COMSOL software to predict and calculate the distribution of temperature on the various regions of the parent metal and the welded joints. The predicted and finite element analysis (FEA) simulating the results of the distribution of peak temperatures were found to be consistent with the experimental values. In addition to this, a parametric experimental investigation was conducted to identify the most influential process parameter that plays a significant role in the peak temperature distribution during FSW of AZ80A Mg alloy. Linear contributions by the input process parameters of FSW, namely, traversing speed, rotating tool speed and axial force on the peak temperature were observed to be 32.82 %, 41.65 % and 21.76 %, respectively.

Initial Results of Monitoring the Temperature on the Facade of Office Building

2019 ◽  
Vol 887 ◽  
pp. 411-418
Author(s):  
Peter Juras ◽  
Radoslav Ponechal ◽  
Daniela Štaffenová
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Full Scale ◽  
Office Building ◽  
Wind Flow ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Measurement Units ◽  
Weather Stations ◽  
Initial Results

This paper deals with creating of the unique measurement units on the building façade, which enable the possibility to conduct a full-scale measurement of the outdoor climate parameters around the building. The façade of the Research center building, which is a part of University of Zilina campus, is equipped with 36 weather stations to measure the outdoor climate conditions and impact of the building on the approaching wind flow, air temperature distribution, solar radiance impact on the façade etc.In this article, the change of temperatures within the time and place on the facade (sides, position, time), is monitored. This takes into account the surroundings of the building and the temperature on the façade and comparison to the measured “basic” air temperature.

Monitoring of the Airflow around the Façade of an Office Building

2019 ◽  
Vol 887 ◽  
pp. 579-586
Author(s):  
Peter Juras ◽  
Radoslav Ponechal
Keyword(s):  
Temperature Distribution ◽  
High Resolution ◽  
Air Temperature ◽  
Office Building ◽  
Wind Flow ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Measurement Units ◽  
Weather Stations ◽  
Very High

This paper describes measurement units on the building façade, which enable the possibility to conduct a full-scale measurement with a very high resolution of the outdoor climate parameters around the building. The façade of the Research center building, which is a part of University of Zilina campus, is equipped with 36 weather stations to measure the outdoor climate conditions and impact of the building on the approaching wind flow and air temperature distribution, solar radiance impact on the façade, etc. In this article, the wind flow around the building in different heights is monitored, analyzed and compared to the free wind flow.

Air Flow Modelling of a Multi-Storey Office Building

2013 ◽  
Vol 361-363 ◽  
pp. 833-844
Author(s):  
Chong Jie Wang ◽  
Wei Wei Liu
Keyword(s):  
Temperature Distribution ◽  
Natural Ventilation ◽  
Air Flow ◽  
Comfort Level ◽  
Office Building ◽  
Temperature Stratification ◽  
Air Distribution ◽  
Flow Modelling ◽  
Ventilation Strategies

Indoor fresh air distribution, temperature stratification and temperature distribution are consider to be the essential indicators when comes to evaluation of the comfort level for internal ventilation environment, particularly for natural ventilated space as target office building. It can be identified that the targeting building has been well designed in the respect of natural ventilation strategies where both cross and stack strategies have been adopted, but it is also obvious that under combined buoyancy and wind driven mode alternative problems appears.

Finite element modeling and analysis of powder mixed electric discharge machining process for temperature distribution and volume removal considering multiple craters

2014 ◽  
Vol 05 (03) ◽  
pp. 1450009 ◽  
Author(s):  
Hardeep Singh ◽  
Anirban Bhattacharya ◽  
Ajay Batish
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Finite Element Modeling ◽  
Electric Discharge ◽  
Material Removal ◽  
Peak Temperature ◽  
Machining Process ◽  
Electric Discharge Machining ◽  
Element Modeling ◽  
Pulse On Time

Powder mixed electric discharge machining (PMEDM) is one of the modern developments in electric discharge machining (EDM) process. In the present work, finite element modeling has been carried out considering randomly oriented multiple sparks during PMEDM. Transient thermal analysis is done to obtain temperature distribution, volume removal, and proportion of volume removed by melting and evaporation at different current, pulse on time and fraction of heat that enters to work piece. Gradually growing spark behavior and Gaussian distribution of heat source is used to simulate multiple craters. Temperature distribution along radial direction shows peak temperature at center of spark and thereafter a gradual decrease with increase in radial distance. Along depth direction temperature sharply decreases that forms wider craters with shallow depth in PMEDM. Peak temperature and volume removal increases with current more rapidly. Volume removal by melting is much higher than evaporation at lower current settings and with higher current almost equal amount of material is removed by melting and evaporation thus reducing the re-solidification of melted material. Current plays a significant role behind the contribution of material removal by evaporation followed by fraction of heat. Increase in pulse on duration increases the total volume of material removal however does not significantly increase the proportion of volume removal by vaporization.

Experimental investigation and numerical simulation on continuous wave laser ablation of multilayer carbon fiber composite

2015 ◽  
Vol 231 (8) ◽  
pp. 674-682 ◽  
Author(s):  
Lianchun Long ◽  
Yao Huang ◽  
Jinfeng Zhang
Keyword(s):  
Laser Ablation ◽  
Temperature Distribution ◽  
Carbon Fiber ◽  
Continuous Wave ◽  
Fiber Composite ◽  
Rear Surface ◽  
Peak Temperature ◽  
Transient Temperature ◽  
Carbon Fiber Composite ◽  
Carbon Fiber Epoxy

Laser beam machining is one of the most widely used advanced processing techniques, which can be applied to compound materials. As a large number of photons are absorbed into the composite, the subsequent local heat storage, charring and potential delamination make the study for the effect of laser on complex materials become significant. In this paper, a carbon fiber epoxy composite laminated sheet is irradiated by continuous wave chemical oxygen iodine laser. The peak temperature of front surface, the temperature distribution of rear surface, and the appearance of ablation zone are presented. Further, based on the birth–death elements technique of finite element method, a three-dimensional model for simulating the transient temperature distribution and material removal has been developed under the same condition. The results reveal that the peak temperature of irradiated region ranges from 2800 K to 3100 K, and the center point shows a higher temperature rise rate than the surroundings in the irradiated zone. The measured data and predicted data are in a good consistency, which suggests that the numerical model is appropriate for simulating laser ablation of carbon fiber epoxy composites.

Research on the Combustion Characteristics of Small-Scaled Ethanol Pool Fire of Different Aspect Ratios

2011 ◽  
Vol 347-353 ◽  
pp. 1161-1165
Author(s):  
Cui Peng Kuang ◽  
Yuan Zhou Li ◽  
Shi Zhu ◽  
Shao Hua Mao
Keyword(s):  
Temperature Distribution ◽  
Aspect Ratio ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Pool Fire ◽  
Aspect Ratios ◽  
Fire Experiment ◽  
The Difference ◽  
Experimental Values ◽  
Centerline Temperature

Four groups of small-scaled ethanol pool fire experiment with different aspect-ratio(s) is undertaken, to gauge the mass loss rate of fuel as well as the plume centerline temperature distribution. Comparison of plume centerline temperature is made between the theoretical values estimated by Heskestad plume model and experimental results, which indicates that: with the increasing of s, the difference between theoretical values and experimental values tend to grow greater; and when s≈1, theoretical values and experimental values cohere well.

scholarly journals Post Fire Transient Temperature Distribution in Drum Type Packages

2006 ◽  
Author(s):  
Allen C. Smith
Keyword(s):  
Temperature Distribution ◽  
Thermal Resistance ◽  
Heat Generation ◽  
Thermal Response ◽  
Internal Resistance ◽  
Peak Temperature ◽  
Transient Temperature ◽  
Containment Vessel ◽  
Transient Temperature Distribution ◽  
Parametric Studies

This study investigates the temperature distribution in an idealized cylindrical package subjected to the HAC Fire transient. Cases for several common overpack materials, with thermal conductivity spanning two orders of magnitude, are considered. The results show that the interior temperature distribution and maximum interior temperature are determined by the heat generation of the contents and the thermal resistance of the package materials. Heat generation has a dominant effect on the peak temperature in the center (containment vessel region) of the package, when the internal thermal resistance is high. For cases where the internal resistance is low, heat conducted into the interior during the fire determines the peak temperature in the center, containment vessel region. The thermal wave effect, where the interior temperature continues to rise after the end of the fire exposure, is present in all cases. The study complements the parametric studies of effects of thermal properties on thermal response of packages which were previously reported.

Toxicity of the Atmosphere in an Upstairs Room Caused by Inflow of Fire Effluent Gases Rising from a Burn Room

1993 ◽  
Vol 11 (3) ◽  
pp. 195-209 ◽  
Author(s):  
Tokio Morikawa ◽  
Eiji Yanai ◽  
Takeo Okadaa ◽  
Kisen Sato
Keyword(s):  
Construction Materials ◽  
Cohb Level ◽  
Fire Experiment ◽  
Blood Cyanide ◽  
Fire Experiments

Fire experiments were repeatedly conducted in a fire-resistant 2-story house to investigate the toxicity of atmosphere in its second floor room, using one of the first floor rooms as a burn room, which was fully equipped with construction materials and house contents. In each fire experiment only the size of the opening of the doorway to the second floor room was varied. The tox icity was found to become sufficiently high to cause death to rabbits exposed to cooled gases taken from any location in the second floor room, even when the doorway to the second floor room was almost completely closed. Major toxicants were limited to CO and HCN, as in our earlier study [1]. Although the blood cyanide level was always below 2.0 μg/mL, HCN must have had an important role in causing death to the rabbits, because the COHb level mostly remained below 50%.

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