scholarly journals Performance analysis of a heat transfer and sub-grid chemical reaction distributed activation energy model for fire simulations

2018 ◽  
Vol 37 (1) ◽  
pp. 18-46 ◽  
Author(s):  
Abhishek Bhargava ◽  
Patrick Van Hees ◽  
Bjarne Husted ◽  
Antonio Rodolfo Junior ◽  
Corina Neumeister
Keyword(s):  
Heat Transfer ◽  
Mass Loss ◽  
Heat Release ◽  
Chemical Reaction ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Heat Released

A heat transfer and sub-grid chemical reaction kinetic model for solid phase combustion of a charring polymer is presented based on distributed reactivity modeling approach. The model is used to compute flammability parameters of a polymer sheet of a given thickness to simulate test results of a cone calorimeter experiment. Comparison of model simulations with cone calorimeter test data shows that it gives reasonable prediction of mass loss rate, heat release rate, and total heat released of poly-vinyl chloride (PVC) and ethyl vinyl acetate–aluminum tri-hydroxide (EVA-ATH). The solution of governing equations with the current form of distributed reactivity modeling model poses numerical challenges due to appearance of a double integral in the chemical reaction model. Hence, an analytical approximation has been derived to solve mass and energy conservation equations representing the model. Simulation results indicate that with the approximated form of the distributed reactivity modeling model, along with the input parameters retrieved from literature, the model shows comparatively good predictions for EVA-ATH for mass loss rate, heat release rate, and total heat released, but calculates under-predicted values for PVC.

scholarly journals FIRE TESTS ON WOOD PRODUCTS SUBJECTED TO DIFFERENT HEAT FLUXES

2010 ◽  
Vol 16 (4) ◽  
pp. 484-490 ◽  
Author(s):  
Romualdas Mačiulaitis ◽  
Vladas Praniauskas
Keyword(s):  
Mass Loss ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Wood Products ◽  
Fire Tests ◽  
Smoke Production

The paper analyses three different wood products used for research exposing them to the surface heat flow density of 30 kW/m2, 50 kW/m2 and 70 kW/m2 and applying the test method described in ISO 5660–1 Reaction‐to‐fire tests – Heat release, smoke production and mass loss rate – Part 1: Heat release rate (Cone calorimeter method). Research was performed applying 18 mm and 29 mm thick laminated wood chipboards and 24 mm thick medium density fibreboard. The paper provides an overview of the fire properties of wood products and discusses testing methods and the percentage composition of the tested wood products. Mean time to their ignition was determined. The mean values of the maximum heat release rate and time required to achieve them were investigated. Furthermore, the measurements of the released heat and efficient heat of combustion were taken. Further research covers the performance of statistic analysis, deriving empiric equations, correlation and determination coefficients, standard errors and Student criterion. The results of research are summarized. Conclusions are provided at the end of the paper. Santrauka Straipsnyje nagrinejami trys skirtingi medienos gaminiai, su kuriais atlikti tyrimai veikiant 30 kW/m2, 50 kW/m2bei 70 kW/m2 paviršiniais šilumos srautais taikant ISO 5660–1 “Reaction‐to‐fire tests – Heat release, smoke production and mass loss rate – Part 1: Heat release rate (Cone calorimeter method)” bandymo metoda. Tyrimai atlikti su 18 mm ir 29 mm storio laminuotomis medžio drožliu plokštemis bei 24 mm storio vidutinio tankio plaušo plokšte. Darbe apžvel‐giamos medienos gaminiu gaisrines savybes. Aptariama bandymo metodika ir tirtu medienos gaminiu procentine sudetis. Nustatytas vidutinis laikas iki ju užsidegimo. Ištirti vidutiniai maksimalios šilumos išsiskyrimo greičio ir laiko iki ju pasiekimo dydžiai, taip pat išmatuota visa išskirta šiluma ir efektyvi degimo šiluma. Atlikta statistine analize, gautos em‐pirines lygtys, koreliacijos bei determinacijos koeficientai, standartines paklaidos bei Stjudento kriterijai. Apibendrinami tyrimo rezultatai. Darbo pabaigoje suformuluojamos išvados.

Retardant Properties of Nanosilica/PTFE Nanoparticals-Reinforced Polypropylene

2014 ◽  
Vol 1004-1005 ◽  
pp. 77-84 ◽  
Author(s):  
Zhen Lu Zhang ◽  
Dong Li Li ◽  
Wen Cai Xu ◽  
Ya Bo Fu ◽  
Rui Juan Liao
Keyword(s):  
Mass Loss ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Thermoplastic Polymer ◽  
Maximum Heat ◽  
Average Mass ◽  
Melting Characteristics

This work reports the flammability properties of Nanocomposites reinforced with silica and PTFE nanoparticles and toughened with an elastomeric ethylene-vinyl acetate (EVA). Through trial and simulation study of the flame retardant thermoplastic polymer and melting characteristics of PP in the combustion process.The study found that modified PP composites have good flame retardancy compared to PP in case of fire relatively.In the study,the melting characteristics of the thermoplastic polymer affected the mass loss rate in the combustion stage.Nanocomposites experienced low plastic mass loss compared with PP, this has been related to pyrolysis mechanism of polymer.In general,The polymers undergoing depolymerization will lead to a rapid volatilization and therefore experienced much less melting.The results showed that:total heat release of nanocomposites was higher than polypropylene, while the average heat release rate, the maximum heat release rate, the average effective heat of combustion, the average mass loss rate, the average specific extinction area, and other indicators were lower than polypropylene.

scholarly journals INVESTIGATION THE FIRE HAZARD OF PLYWOODS USING A CONE CALORIMETER

Wood Research ◽  
2021 ◽  
Vol 66 (6) ◽  
pp. 933-942
Author(s):  
ZHIGANG WU ◽  
XUE DENG ◽  
LIFEN LI ◽  
LIPING YU ◽  
JIE CHEN ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
High Efficiency ◽  
Fire Hazard ◽  
Mass Loss Rate ◽  
Fire Retardant ◽  
Safety Level

A high-efficiency fire retardant composition was prepared with dicyandiamide, phosphoric acid, boric acid, borax, urea and magnesium sulfate and it was used to process veneers which were then to prepare the plywood. Meanwhile, heat release and smoke release from combustion of plywood were tested by a cone calorimeter, including heat release rate, mass loss rate, CO yield, CO2 yield and oxygen consumption. Results showed that the plywood with this fire retardant treatment had the better flame-retardant performance and smoke suppression effect as well as the stronger char-forming capability compared to plywood without fire retardant treatment. The average heat release rate, total heat release, average effective heat of combustion, total smoke release, CO yield and oxygen consumption of the plywood with fire retardant treatment were decreased by 63.72%, 91.94%, 53.70%, 76.81%, 84.99% and 91.86%, respectively. Moreover, the fire growth index of plywood treated by fire retardant was relatively low (3.454 kW·m-2·s-1) and it took longer time to reach the peak heat release rate, accompanied with slow fire spreading. The fire performance index was relatively high (0.136 s·m2·kW-1) and it took longer time to be ignited, thus leaving a long time for escaping at fire accidents. The fire hazard of plywood with fire retardant treatment was low, and its safety level was high.

scholarly journals Use of the cone calorimeter to detect seasonal differences in selected combustion characteristics of ornamental vegetation

2005 ◽  
Vol 14 (3) ◽  
pp. 321 ◽  
Author(s):  
David R. Weise ◽  
Robert H. White ◽  
Frank C. Beall ◽  
Matt Etlinger
Keyword(s):  
Moisture Content ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Mass Loss Rate ◽  
Combustion Characteristics ◽  
Release Rates ◽  
Intermediate Scale ◽  
Time To Ignition

The flammability of living vegetation is influenced by a variety of factors, including moisture content, physical structure and chemical composition. The relative flammability of ornamental vegetation is of interest to homeowners seeking to make their homes ‘fire safe’. The relative importance of the factors influencing fire behaviour characteristics, such as flammability, is unknown. In the present study, oxygen consumption calorimetry was used to obtain selected combustion characteristics of ornamental vegetation. Peak heat release rate, mass loss rate, time to ignition and effective heat of combustion of 100 × 100-mm samples of foliage and small branches were measured using a bench-scale cone calorimeter. Green and oven-dry samples of 10 species were collected and tested seasonally for a period of 1 year. Similar measurements were made on whole shrubs in an intermediate-scale calorimeter. The range of cone calorimeter peak heat release rates for green and oven-dry samples was 1–176 and 49–331 kW m−2, respectively. Moisture content significantly reduced heat release rates and increased time to ignition. Peak heat release rates for Olea europea and Adenostoma fasciculatum were consistently highest over the year of testing; Aloe sp. consistently had the lowest heat release rate. The correlation of peak heat release rates measured by the cone calorimeter and an intermediate-scale calorimeter was statistically significant yet low (0.51). The use of the cone calorimeter as a tool to establish the relative flammability rating for landscape vegetation requires additional investigation.

Research on the Capability and Application of Flame Retardant Cable

2011 ◽  
Vol 217-218 ◽  
pp. 631-635
Author(s):  
Yong Wang
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Heat Release Rate ◽  
Release Rate ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Fire Retardant ◽  
Flame Retardant Property ◽  
Time To Ignition ◽  
Carbon Monoxide Yield

This paper, analyzes some parameters with the help of Cone Calorimeter (CONE) for the time to ignition, smoke extinction area, heat release rate, carbon monoxide yield and mass loss rate. The results show that the fire retardant agents affect KVV’s flame retardant property. Such as TTI ( time to ignition ) is prolonged to nearly two times, and the average HRR ( heat release rate ) reduces about 18% compared with the ordinary one and the maximum HRR down about 33%of its counterpart.

Analysis of Combustion Characterization of Computer Monitor and Paper in Conic Calorimeter Test

2011 ◽  
Vol 282-283 ◽  
pp. 169-172
Author(s):  
Jia Lei Tan ◽  
Yu Shu Xie ◽  
Xiao Feng Zhang ◽  
Tong Wang
Keyword(s):  
Mass Loss ◽  
Production Rate ◽  
Release Rate ◽  
Radiation Intensity ◽  
Cone Calorimeter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Growth Index ◽  
Heat Radiation ◽  
Fire Growth

Small-scale burning experimental study of computer monitors and paper was done based on cone calorimeter. The small and middle scale fires were simulated by changing the heat radiation intensity of cone calorimeter. The heat release rate, mass loss rate and production rate of CO was measured in experiment. The data of mass loss rate and CO production rate is fitted, and the formula of its change with time is obtained. The computer monitor has slow pyrolysis speed on the 35 kW/m2, and the carbon layer on surface gradually thickened. So the heat will accumulate, and then the pyrolysis speed increases. The heat release rate reaches to the second peak. The fire growth index of monitor increases as the heat radiation intensity. But the fire growth index of paper has the opposition trend. The CO production rate of computer monitor is larger than paper’s. The experiment results can reflect the combustion characteristics of computer monitor on real fires.

Research on the Combustibility of PI Needle Punched Nonwovens by Cone Calorimeter

2011 ◽  
Vol 332-334 ◽  
pp. 1335-1338
Author(s):  
Shu Gan Li ◽  
Xiao Ning Jiao ◽  
Qing Long Jia
Keyword(s):  
Mass Loss ◽  
Heat Release ◽  
Heat Release Rate ◽  
Fire Resistance ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Ignition Time ◽  
Total Heat ◽  
Total Heat Release ◽  
Resistance Performance

This paper demonstrates the combustibility of PI needle punched nonwovens by Cone Calorimeter. Ignition parameter, heat release parameters, smoke and toxicity parameters and mass loss parameters of the fabric were obtained from it. It was found that ignition time is 38 s; the peak of heat release rate is 65 kW/m2; total heat release is 7 MJ/m2; smoke release rate is 1.5 L/s; smoke factor is 1.3 MW/m2 and mass lose rate is 73.3%. Therefore the results show that PI needle punched nonwovens has excellent fire-resistance performance.

The Non-Combustibility of PTFE Fabric

2011 ◽  
Vol 295-297 ◽  
pp. 349-352 ◽  
Author(s):  
Li Jun Qu ◽  
Xiao Qing Guo ◽  
De Ling Chi ◽  
Ya Ning Sun
Keyword(s):  
Mass Loss ◽  
Heat Release ◽  
Cone Calorimeter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Total Heat ◽  
Total Heat Release ◽  
Time To Ignition ◽  
Loss Parameter ◽  
Effective Heat Of Combustion

The non-combustibility of PTFE fabric0s was investigated by Cone Calorimeter in this paper. Ignition parameter, heat release parameter, mass loss parameter and smoke parameter of PTFE fabrics were obtained. The Time to Ignition of PTFE fabric and PTFE/Nomex fabric were 60 and 24s respectively, and the Heat Release Rate were 9.28 and 65.52kw/m2 respectively. The Total Heat Release of PTFE fabric and PTFE/Nomex fabric increased with time, and the Total Heat Release of PTFE/Nomex was much higher than that of PTFE fabric. The Effective Heat of Combustion were 5.06 and 9.94mj/kg respectively, the maximum of mass loss rate of PTFE fabric was larger than that of PTFE/Nomex fabric, and the curve of mass loss rate of PTFE fabric changed rather slightly. It can be concluded that the non-flame properties of PTFE fabric was more remarkable than that of PTFE/Nomex fabric.

A Method Evaluating Fire Hazard of Multiple-Layer Cable Tray and its Validation

2017 ◽  
Author(s):  
Xianjia Huang ◽  
Kun Bi ◽  
Jun Xiao ◽  
Lan Peng ◽  
He Zhu ◽  
...  
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Zone Model ◽  
Fire Source ◽  
Multiple Layer ◽  
Cat Model ◽  
Tray Fire

Multi-layer cable tray fire has special burning characteristics that the cable flame spreads horizontally along cable tray and propagates vertically from bottom layer to upper layer at the same time. With respect of accuracy and speed of calculation, simulation of multi-layer cable tray fire remains a challenge for fire models. In this paper, a method is proposed to simulate multi-layer cable tray fire. By developing a more accurate fire source description, this method can provide accurate simulation for multi-layer cable tray fire rapidly. In this method, Firstly, the heat release rate of each burning cable tray is evaluated by FLASH-CAT model. Based on the results from FLASH-CAT, a more accurate fire source definition for multiple lay cable tray is developed for zone model. Taking account of each burning cable tray considered as one fire source point, zone model is applied to predict the fire dynamics process. In order to validate this method, four-layer cable tray fire experiments and replicated experiments were carried out in a confined compartment. The histories of mass loss rate of cable tray and temperatures at the middle of compartment were recorded during the cable fire. From the replicated experimental results of total mass loss rate, it is concluded that the four-layer cable tray fire experiment has good repetition in this scenario. Vertical temperature profile shows that the fire circumstance generated by multiple-layer cable tray burning can be divided into upper hot layer and lower cool layer, which conforms to the basic assumption of zone model. As a consequence, the zone model can be applied to simulating multiple-layer cable tray fire. By comparing the experimental total heat release rate with predictions, it is found that characteristics of multiple-layer cable tray fire are well captured. On account of good prediction on overall heat release rate for multi-layer cable tray fire, predicted heat release rate for each burning cable layer by FLASH-CAT model is believed to be reliable. Then, each burning cable layer is set as one fire source and the heat release rate of each burning cable layer is input into zone model, respectively. The comparisons between simulations and experimental data show that the predicted upper layer temperature and lower layer temperature agree well with experimental data. As a result, it can be concluded that this method provides reliable prediction for multiple-layer cable tray fire rapidly.

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