scholarly journals Thermodynamic and Kinetic Characteristics of Combustion of Discrete Polymethyl Methacrylate Plates with Different Spacings in Concave Building Facades

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 167
Author(s):  
Weiguang An ◽  
Lujun Peng ◽  
Minglun Cai ◽  
Kaiyang Hu ◽  
Song Li ◽  
...  
Keyword(s):  
Polymethyl Methacrylate ◽  
Flame Spread ◽  
Structure Factor ◽  
Turning Point ◽  
Fire Risk ◽  
Flame Height ◽  
Hazard Evaluation ◽  
Spread Rate ◽  
Building Facades ◽  
Flame Spread Rate

Polymethyl methacrylate plates are widely applied to buildings, producing significant fire hazards. It lacks a theoretical basis for the fire risk assessment of polymethyl methacrylate in concave building facades. Therefore, experimental methods are used to investigate combustion characteristics of discrete polymethyl methacrylate plates in a concave building facade. Influences of fuel coverage and structure factor are investigated, which is scant in previous works. When structure factor is invariable, average flame height increases first and then decreases as fuel coverage increases, and the turning point is between 0.64 and 0.76. In total, three different patterns of pyrolysis front propagation are first observed for different fuel coverages. Flame spread rate first increases and then decreases as fuel coverage rises, and the turning point is also between 0.64 and 0.76. When fuel coverage is invariable, the flame spread rate first increases and then decreases with increasing structure factor, and the turning point is 1.2. A model for predicting the flame spread rate of discrete polymethyl methacrylate is also developed. The predicted values are consistent with experimental results. Fuel spread rate of discrete polymethyl methacrylate rises as the fuel coverage increases. The above results are beneficial for thermal hazard evaluation and fire safety design of polymethyl methacrylate used in buildings.

scholarly journals Experimental Study on Flammability and Flame Spread Characteristics of Polyvinyl Chloride (PVC) Cable

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2789
Author(s):  
Weiguang An ◽  
Yanhua Tang ◽  
Kai Liang ◽  
Tao Wang ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Polyvinyl Chloride ◽  
Flame Spread ◽  
Fire Hazard ◽  
Flame Height ◽  
Maximum Temperature ◽  
Hazard Evaluation ◽  
Total Width ◽  
Spread Rate ◽  
Cable Structure ◽  
Flame Spread Rate

Polyvinyl chloride (PVC) is widely applied in cables as insulation materials, which are vital for operation and control of industrial processes. However, PVC cables fires frequently occur, arousing public concern. Therefore, experimental methods are used to study flammability and flame-spread characteristics of PVC cable in this paper. Influences of cable structure and number are investigated, which is scanty in previous works. As cable core number of single cable or cable number of multiple cables rises, average flame height and width increase while the increment decreases. Formulas concerning dimensionless flame height and single cable diameter (or total width of multiple cables) are obtained. The former is negatively correlated with the latter. For single cable, convective heat transfer is dominant, and flame-spread rate decreases as cable core number increases. Cable maximum temperature, which drops first and then rises as cable core number increases, is observed in the cable core area. For multiple cable, the flame-spread rate increases as cable number increases. As the cable number rises, the length of pyrolysis and combustion zone increases while the maximum temperature of cable surface decreases. This work is beneficial to fire hazard evaluation and safety design of PVC cables.

Effect of Sample Width on Downward Flame Spread over Typical Energy Conservation Material at a High Elevation Area

2014 ◽  
Vol 664 ◽  
pp. 199-203 ◽  
Author(s):  
Wei Guang An ◽  
Lin Jiang ◽  
Jin Hua Sun ◽  
K.M. Liew
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
High Elevation ◽  
Flame Height ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Sample Width ◽  
Downward Flame Spread

An experimental study on downward flame spread over extruded polystyrene (XPS) foam at a high elevation is presented. The flame shape, flame height, mass loss rate and flame spread rate were measured. The influences of width and high altitude were investigated. The flame fronts are approximately horizontal. Both the intensity of flame pulsation and the average flame height increase with the rise of sample width. The flame spread rate first drops and then rises with an increase in width. The average flame height, mass loss rate and flame spread rate at the higher elevation is smaller than that at a low elevation, which demonstrates that the XPS fire risk at the higher elevation area is lower. The experimental results agree well with the theoretical analysis. This work is vital to the fire safety design of building energy conservation system.

Experimental study of moisture content effects on horizontal flame spread over thin cotton fabric

2018 ◽  
Vol 89 (15) ◽  
pp. 3189-3200 ◽  
Author(s):  
Yunji Gao ◽  
Guoqing Zhu ◽  
Hui Zhu ◽  
Weiguang An ◽  
Yu Xia
Keyword(s):  
Moisture Content ◽  
Cotton Fabric ◽  
Flame Spread ◽  
Extreme Values ◽  
Ignition Time ◽  
Convective Heat Transfer Coefficient ◽  
Flame Height ◽  
Spread Rate ◽  
Untreated Cotton ◽  
Flame Spread Rate

In this paper, moisture content effects on horizontal flame spread were experimentally investigated using 0.245 mm thick, 28 cm tall and 28 cm wide untreated cotton fabric sheets with various moisture contents varying from 0 to 34%. The pyrolysis spread rates, flame heights and ignition times were obtained and analyzed. The corresponding results are as follows: as moisture content increases, the flame height and spread rate first increase and then decrease. In contrast, the ignition time shows an opposite trend with moisture content. The extreme values are observed in cases of 2% moisture content samples. Moreover, the flame spread rate in the warp direction is larger than that in the weft direction. For horizontal flame spread, the moisture content has the effect of consuming part of the heat feedback, which can play a role in reducing the flame spread rate; simultaneously, the moisture content can enlarge flame size and increase the convective heat transfer coefficient, thereby resulting in an increase in flame spread rate. The non-monotonous trend in pyrolysis spread rate is the result of competition between these effects.

Effect of Sample Width on Characteristics of Flame Spread across Eucalyptus Wood Surface

2013 ◽  
Vol 401-403 ◽  
pp. 767-770
Author(s):  
Gui Hong Wu ◽  
Yi Qiang Wu ◽  
Yun Chu Hu ◽  
Xiao Dan Zhu
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flame Height ◽  
Spread Rate ◽  
Eucalyptus Wood ◽  
Flame Spread Rate ◽  
Sample Width ◽  
The Relationship

To study the effect of sample width on flame spread characteristics, a series of laboratory-scale experiments were conducted employing eucalyptus wood with width from 3 to 7 cm. Flame dimension, flame spread rate and mass loss rate were obtained. The relationship between these flame spread characteristics and sample width was explored. Both the dimensionless average flame height and depth vary as the-n power of sample width. With the increase of sample width, both the flame spread rate and mass loss rate first decrease and then rise. The minimum values appear when sample width measures 6 cm.

Experimental Study on Downward Flame Spread across XPS Surface

2013 ◽  
Vol 753-755 ◽  
pp. 445-451
Author(s):  
Wei Guang An ◽  
Hua Hua Xiao ◽  
Jin Hua Sun ◽  
Wei Gang Yan ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flame Height ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Stage 1 ◽  
Exponential Change ◽  
Downward Flame Spread

To study downward flame spread across XPS surface, a series of laboratory-scale experiments were conducted. Typical flame spread characteristics were obtained. The flame spread process comprises four stages. There are twice accelerations during flame spread. The influence of maximum flame height on flame spread rate is not significant. The predicted flame spread rate utilizing mass loss rate is lower than the measured value. Three stages: increasing stage, stable stage and decreasing stage are observed in both change of maximum flame height and flame area. The changing trend of mass loss rate is similar to that of maximum flame height. For stage 1 and stage 3, exponential change of mass loss rate with time is found. The mass loss rate is constant for stage 2. The heat flux to the preheating zone is higher than that to surrounding environment. Experimental results agree well with theoretical analysis.

scholarly journals Experimental study on flame propagation over overload-wire under varying inclination Angle

2021 ◽  
Vol 233 ◽  
pp. 01012
Author(s):  
Hu Wen ◽  
Xiangtao Zhao ◽  
Qing Tian ◽  
Weifeng Wang ◽  
He Jian
Keyword(s):  
Flame Propagation ◽  
Inclination Angle ◽  
Flame Spread ◽  
Low Voltage ◽  
Flame Height ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Conducting Wire ◽  
Flame Shape ◽  
The Wire

To better understand the process of fire caused by conducting wire, based on the study of overload of the low-voltage wire, the theoretical analysis of flame spread mechanism of overload-wire was proposed, and the functional relationship between flame shape characteristics and flame spread speed, current, and inclination angle was studied. The results show that: (1) the theoretical model of flame propagation can well reflect the changes of thermodynamic parameters in the process of flame propagation, and it is in better agreement with the experimental results. (2) When the current value is constant, with the increase of the inclination angle of the wire (0°-90°), the flame is elongated along the wire direction, the width of the flame base increases, and the angle between the flame front and the wire decreases. When the inclination angle is fixed, with the increase of the inclination angle of the conductor, the flame shape becomes more "high and wide" and the flame height increases at the same time. (3) When the current is constant, the flame spread rate increases with the increase of wire inclination angle; when the inclination angle is constant, the flame spread rate decreases sharply with the increase of current.

Large-Scale Experimental Investigation of the Fire Characteristics Parameters of Methanol in Coal Chemical Industry

2015 ◽  
Vol 713-715 ◽  
pp. 2745-2749
Author(s):  
Lu Wang ◽  
Yi Xing Bi ◽  
Wei Wu ◽  
Da Jun Xu
Keyword(s):  
Heat Flux ◽  
Flame Spread ◽  
Large Scale ◽  
Flame Height ◽  
Characteristic Parameters ◽  
Spread Rate ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Flame Spread Rate ◽  
Fire Characteristics

A steel channel with the size of 30×2×1.2 m was made to simulate the full surface fire of 50000 m3methanol tank in coal-to-olefins industry. Some fire characteristic parameters of methanol were investigated, including flame spread rate, flame height, temperature distribution and radiation heat flux distribution. It is found that the flame spread rate of methanol is 1.98 m/s and the flame height could reach to 3.2 m. The temperature of methanol flame is first up and then down with the increase of height, while the highest temperature is 768oC. It is also found that the radiation heat flux of methanol flame is in the changes between 4.4 kW/m2and 12.2 kW/m2. The feature of methanol fire is different from the normal oil fire, which is worth for us to pay more attention.

Experimental Study on Flame Spread over Inclined PMMA and PE Slabs

2018 ◽  
Vol 775 ◽  
pp. 390-394 ◽  
Author(s):  
Kun Zhao ◽  
Xiao Dong Zhou ◽  
Fei Peng ◽  
Xiao Yu Ju ◽  
Li Zhong Yang
Keyword(s):  
Experimental Study ◽  
Steady State ◽  
Polymethyl Methacrylate ◽  
Solid Surface ◽  
Flame Spread ◽  
High Density Polyethylene ◽  
Spread Rate ◽  
Fire Plume ◽  
Flame Spread Rate ◽  
Series Of Experiments

The effects of orientation on flame spread over the upper surface of PMMA and PE slabs were studied through a series of experiments. For fuel inclined angles smaller than 75° in this study, flame spread would arrive a steady-state stage finally. The flame spread rate and the angle of the fire plume near pyrolysis front in the steady-state stage were measured to investigate the differences between flame spread over melting and non-melting solids. Compared to the flame spread over polymethyl methacrylate (PMMA), the melting behaviors of high density polyethylene (PE) significantly decrease the flame spread rate, which is mainly attributed to the decreased size of fire plume and reduced interactions between fire plume and solid surface. The angles of the fire plume in the steady-state stage under different fuel inclined angles were measured to better understand the melting effects on flame spread over the inclined solid surface.

Experimental Investigation of Downward Flame Spread over RPU Samples

2013 ◽  
Vol 328 ◽  
pp. 921-925
Author(s):  
Yuan Ming Wang ◽  
Yong Ming Zhang ◽  
Heng Ze Zhao ◽  
Lan Ming Zhao
Keyword(s):  
Flame Spread ◽  
Combustion Process ◽  
Flame Height ◽  
Pulsation Frequency ◽  
Insulation Material ◽  
Spread Rate ◽  
Energy Feedback ◽  
Flame Spread Rate ◽  
Sample Width ◽  
Downward Flame Spread

The combustion process of polymer is a complex coupling of energy feedback from flame to fuel surface with degradation of polymer. In this paper, a series of comparative laboratory-scale experiments were carried out to study the effect of sample width on downward flame spread over the rigid polyurethane (RPU) foam, a typical thermal insulation material. The variations of some important parameters such as flame height, pulsation frequency and flame spread rate were measured and analyzed. Results show that if the width fixed, the parameters mentioned above independent with time. If the width less than 25cm, the sample can not burn completely. With the expand of width, average flame height and flame spread rate present the same chang trend that increase first and then decrease and finally reach a steady state, flame pulsation frequency increases first and then decreases since sample width more than 20cm. The heat transfer from flame and pyrolysis zone to virgin region is proportional to the height of flame, and mainly dominated by radioactive regime.

Experimental Study on Downward Flame Spread of Rigid Polyurethane Foam with External Radiation

2014 ◽  
Vol 664 ◽  
pp. 194-198 ◽  
Author(s):  
Xin Ma ◽  
Ran Tu ◽  
Yan Li Zhao ◽  
Nan Wang ◽  
Qi Yuan Xie
Keyword(s):  
Flame Spread ◽  
Mass Loss Rate ◽  
Building Energy ◽  
Flame Height ◽  
External Radiation ◽  
Spread Rate ◽  
Radiation Heat ◽  
Building Energy Conservation ◽  
Building Insulation ◽  
Flame Spread Rate

Research on building insulation materials and their safety is an important topic in the field of building energy conservation. The objective of this paper is to analyze the coupling effects of the width and external radiation on the downward RPU foam flame spread characteristics. The most important flame characteristics including flame height, mass loss rate, flame spread rate were studied experimentally. The results suggest that with increasing external radiation levels, flame spread rate was larger. Under the condition of the external radiation heat flux exceeds a critical level, the RPU foam would be deformed and detached from the board when the flame spread to a certain distance. It also leads to a much higher flame height due to sufficient combustion. Additionally, the flame propagation firstly accelerated when it reaches to a certain distance and then becomes a stable subject to the preheating of the external radiation heat resource.

Sign in / Sign up

Export Citation Format

Share Document