The Mass Burning Rate of n-Heptane Pool Fire Under Dynamic Pressure

2016 ◽  
Author(s):  
Qiuju Ma ◽  
Quanyi Liu ◽  
Runhe Tian ◽  
Junjian Ye ◽  
Rui Yang ◽  
...  
Keyword(s):  
Burning Rate ◽  
Cold Water ◽  
Dynamic Pressure ◽  
Pressure Rise ◽  
Low Pressure ◽  
Pool Fire ◽  
Chamber Pressure ◽  
Pure Liquid ◽  
Mass Burning Rate ◽  
The Impact

Fire safety is critical for safety of airplane operation. During an emergency landing, airplane goes through dramatic external pressure change from cruise altitude to sea level, considering the impact caused by low pressure atmosphere. The objective of this work is to examine the effect of dynamic pressure on the behavior of a horizontally burning diffusion flame over a pool fuel surface based on experimental approach. The experiments were conducted in a large-scale altitude chamber of size 2 m × 3 m × 4.65 m. The pressure rise process was examined under different dynamic pressures from respectively 38 kPa, 64 kPa and 75 kPa to 90 kPa with various pressure rise rates of 100 Pa/s, 150 Pa/s, 200 Pa/s, 250 Pa/s and 300 Pa/s, which is to simulate the airplane landing process from different altitudes. The whole system of the altitude chamber is of unique capability that the pressure in the chamber can be exactly controlled by a powerful pressure controlling system, and the oxygen concentration can maintain at the level about 20%, which are achieved through controlling inlet air flow for oxygen level and outlet gas flow for pressure (static or dynamic) level. A round steel fuel pans of 34 cm in diameter and 15 cm in height were chosen for the pool fire tests. The fuel pan was filled with 99% pure liquid n-Heptane. Cold water is added beneath the fuel layer to cool the pan and minimize the temperature rise in the fuel. Parameters such as mass, mass burning rate, chamber pressure were measured. The results of those tests demonstrated the significant impact to fire behaviors caused by high altitude or low pressure atmosphere.

Experimental study of the mass burning rate in n -Heptane pool fire under dynamic pressure

2017 ◽  
Vol 113 ◽  
pp. 1004-1010 ◽  
Author(s):  
Qiuju Ma ◽  
Quanyi Liu ◽  
Hui Zhang ◽  
Runhe Tian ◽  
Junjian Ye ◽  
...  
Keyword(s):  
Experimental Study ◽  
Burning Rate ◽  
Dynamic Pressure ◽  
Pool Fire ◽  
Mass Burning Rate

Effects of Ambient Pressure on the Mass Burning Rate and Heat Release Rate of n-Heptane Pool Fire

2016 ◽  
Author(s):  
Qiuju Ma ◽  
Quanyi Liu ◽  
Runhe Tian ◽  
Junjian Ye ◽  
Rui Yang ◽  
...  
Keyword(s):  
Heat Release ◽  
Burning Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Large Scale ◽  
Ambient Pressure ◽  
Pool Fire ◽  
Pure Liquid ◽  
Mass Burning Rate ◽  
The Mean

This research aims to investigate the effect of ambient pressure on the burning rate and heat release rate (HRR) of n-heptane pool fire. The experiments were performed in a large-scale altitude chamber of size 2 m×3 m×4.65 m under series of pressure, 24kpa, 38 kPa, 64 kPa and 75 kPa to 90 kPa. A round steel fuel pans of 34 cm in diameter and 15 cm in height was chosen for the pool fire tests. The fuel pan was filled with 99% pure liquid n-Heptane. Experimental results show that the burning rate increases rapidly after ignition until it reaches to the peak, and then maintains at a relatively stable stage. It decreases gradually until the flame extinguishes. The burning time is longer at lower pressure. The mean mass burning rate at the steady burning stage increases exponentially with pressure as ṁ ∼ Pα, with α = 0.68. HRR curve has a similar trend with the burning rate. The maximum HRR increases from 27kW to 62kW as the pressure rises from 24kPa to 90kPa. It is concluded that the ambient pressure has a significant effect on the fire heat release rate, and will further influent on other fire parameters.

Experimental Study of Mass Burning Rate of Liquid Pool Fires Under Dynamic Pressure in an Altitude Chamber

2017 ◽  
Author(s):  
Zhenxiang Tao ◽  
Rui Yang ◽  
Cong Li ◽  
Yina Yao ◽  
Wei Wang
Keyword(s):  
Burning Rate ◽  
Dynamic Pressure ◽  
Ambient Pressure ◽  
Flame Temperature ◽  
Great Influence ◽  
Liquid Pool ◽  
Combustion Characteristics ◽  
Chamber Pressure ◽  
Pool Fires ◽  
Mass Burning Rate

To study the influence of dynamic pressure on the liquid combustion characteristics, two kind sizes of pool fires were studied under varied pressure rates, namely 100Pa/s, 200Pa/s, 300Pa/s from 90kPa to 38kPa in an altitude chamber which size is 2m*3m*4.65m. Combustion characteristics of n-heptane pool fires, such as mass burning rate, flame temperature, chamber pressure were measured in this research. Experiment results show that the mass burning rate of 20cm pool fires, decreases when the ambient pressure reduces, and the variation trend become more sharply when the dynamic pressure rate is increased, while 30cm pool fires at the beginning of the combustion stage almost remain constant, this is because fire heat feedback have a great influence on it. The results also show that compared to the radiation model, pressure model could be linear fitting better in a double logarithm coordinate, and oil pool fires under 300Pa/s of 20cm, 100Pa/s of 30cm the value of α obtained by the fitted curves were more closer to fixed pressure ones.

Modeling on n-Heptane Pool Fire Behavior in an Altitude Chamber

2013 ◽  
Author(s):  
Quanyi Liu ◽  
Wei Yao ◽  
Jiusheng Yin ◽  
Rui Yang ◽  
Hui Zhang
Keyword(s):  
High Altitude ◽  
Burning Rate ◽  
Pressure Effect ◽  
Fire Behavior ◽  
Low Pressure ◽  
Pool Fire ◽  
Low Oxygen ◽  
Fire Plume ◽  
Plume Temperature ◽  
Modeling Data

Airplane as one of the important transport vehicles in our life, its safety problem related to in-flight fire has attracted a wide-spread attention. The combustion behavior of the cabin fire in flight shows some special characteristics because of the high-altitude environment with low-pressure and low oxygen concentration. A low-pressure chamber of size 2 m×3 m×2 m has been built to simulate high-altitude environments, where multiple static pressures for pool fire tests can be configured in the range between standard atmospheric pressure 101.3KPa and 30KPa. Two different sizes of pool fires were tested. Then corresponding modeling were conducted by a LES code FDS V5.5 to examine the mechanism of pressure effect on the n-Heptane pool fire behavior. The burning of liquid fuel was modeled by a Clausius-Clapeyron relation based liquid pyrolysis model. The modeling data was validated against the experimental measurements. The mass burning rate of free-burning pool fire decreases with the decreasing of pressure, which was observed from the modeling to be due to the reduction of flame heat feedback to the fuel surface. Under low pressure, the fire plume temperature increases for the same burning rate. The mechanism of pressure effect on fire behavior was analyzed based on the modeling data.

N-Heptane Pool Fire Behavior in a Controlled Oxygen and Low-Pressure Environment

2014 ◽  
Author(s):  
Quanyi Liu ◽  
Kewei Chen ◽  
Nan Wu ◽  
Jiusheng Yin ◽  
Rui Yang ◽  
...  
Keyword(s):  
High Altitude ◽  
Radiative Heat ◽  
Flame Temperature ◽  
Fire Behavior ◽  
Low Pressure ◽  
Pool Fire ◽  
Fire Tests ◽  
Mass Burning Rate ◽  
Low Oxygen ◽  
Lower Temperature

Fires at high altitude airports have attracted a lot of attention. Such fires show some special characteristics because of the coupling impact of low pressure and low oxygen levels. Some experiments, which were conducted recently at high altitude locations, such as Lhasa and in some low pressure chambers, were usually extinguished due to the limited supply of oxygen. In order to reveal the dependence of fire behavior on pressure comprehensively, a low-pressure chamber with ventilation control of 2×3×4.65m3 in volume has been developed and built, which can allow larger scale fire tests to be conducted and simulate more realistic high-altitude environment. In this study, pool fire tests using 20-cm and 30-cm-diameter pans are configured under five different static pressures, e.g. 101kPa, 75kPa, 64kPa, 38kPa and 24kPa. Each test has been repeated three times. The parameters measured include flame temperature, radiative heat flux, and mass loss etc. It is concluded that under lower pressure, mass burning rate is lower, temperature is higher, and height of the flame is higher, which demonstrated that low pressure fire is more dangerous to the buildings at high altitude airports.

scholarly journals Soot Volume Fraction Measurements by Auto-Compensating Laser-Induced Incandescence in Diffusion Flames Generated by Ethylene Pool Fire

2021 ◽  
Vol 7 ◽  
Author(s):  
Juan J. Cruz ◽  
Ignacio Verdugo ◽  
Nicolás Gutiérrez-Cáceres ◽  
Felipe Escudero ◽  
Rodrigo Demarco ◽  
...  
Keyword(s):  
Burning Rate ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Air Entrainment ◽  
Pool Fire ◽  
Mass Burning Rate ◽  
Data Set ◽  
Pool Surface ◽  
Laser Induced Incandescence ◽  
Radiation Feedback

The main characteristics of pool fire flames are flame height, air entrainment, pulsation of the flame, formation and properties of soot particles, mass burning rate, radiation feedback to the pool surface, and the amount of pollutants including soot released to the environment. In this type of buoyancy controlled flames, the soot content produced and their subsequent thermal radiation feedback to the pool surface are key to determine the self-sustainability of the flame, their mass burning rate and the heat release rate. The accurate characterization of these flames is an involved task, specially for modelers due to the difficulty of imposing adequate boundary conditions. For this reason, efforts are being made to design experimental campaigns with well-controlled conditions for their reliable repeatability, reproducibility and replicability. In this work, we characterized the production of soot in a surrogate pool fire. This is emulated by a bench-scale porous burner fueled with pure ethylene burning in still air. The flame stability was characterized with high temporal and spatial resolution by using a CMOS camera and a fast photodiode. The results show that the flame exhibit a time-varying propagation behavior with a periodic separation of the reactive zone. Soot volume fraction distributions were measured at nine locations along the flame centerline from 20 to 100 mm above the burner exit using the auto-compensating laser-induced incandescence (AC-LII) technique. The mean, standard deviation and probability density function of soot volume fraction were determined. Soot volume fraction presents an increasing tendency with the height above the burner, in spite of a local decrease at 90 mm which is approximately the position separating the lower and attached portion of the flame from the higher more intermittent one. The results of this work provide a valuable data set for validating soot production models in pool fire configurations.

Thermal Interaction Between a Circular Pipe and Diesel Pool Fire

2012 ◽  
Author(s):  
S. Sudheer ◽  
S. V. Prabhu
Keyword(s):  
Burning Rate ◽  
Pool Fire ◽  
Circular Pipe ◽  
Blockage Ratio ◽  
Pool Fires ◽  
Cylindrical Container ◽  
Mass Burning Rate ◽  
Insulating Material ◽  
Fire Experiments

Characterization of pool fires in the presence of cylindrical containers is highly relevant for various applications. A cylindrical container is idealized as a circular pipe packed with insulating material inside. Open pool fire experiments are conducted with a cylindrical container located at the center. The pool fire diameters considered were 0.5 m, 0.7 m and 1.0 m with diesel as the fuel. The cylindrical containers are made of stainless steel 304L. The outer diameters of the pipes are 114 mm, 168 mm and of thickness 8.6 mm, 7.1 mm respectively. The effect of blockage ratio on the mass burning rate for vertical and horizontal orientations of 168 mm cylindrical container is studied. It is observed that there is no significant change in mass burning rate due to the blockage effect. Temperatures are measured at various locations inside the pipes and at the center of the insulation. It is observed that the temperatures along a plane perpendicular to the axis are uniform when the pipes are vertically oriented. IHCP 1D code is applied to estimate the incident heat flux on to the bodies when immersed in open pool fires with different orientations.

Solid Fuel Fire Behavior Under Fixed Pressure in a Low-Pressure Chamber

2015 ◽  
Author(s):  
Rui Feng ◽  
Quanyi Liu ◽  
Runhe Tian ◽  
Kewei Chen ◽  
Rui Yang ◽  
...  
Keyword(s):  
Burning Rate ◽  
Solid Fuel ◽  
Fire Behavior ◽  
Low Pressure ◽  
Pressure Chamber ◽  
Fire Tests ◽  
Mass Burning Rate ◽  
Base Dimension ◽  
The Difference ◽  
Fire Characteristics

To comprehensively reveal the difference of solid fuel fire characteristics at different altitudes, fire experiments of cardboard boxes at multiple static pressures with two configurations filled with shredded office paper were conducted in a low-pressure chamber. The measured parameters are mass burning rate, radiative heat flux, oxygen concentration and heat release rate (HRR) etc. The mass burning rate divided by fire base dimension ṁ/D is correlated against the production of pressure-squared times length-cubed (P2L3) to the power of 0.29 based on current cardboard boxes fire test data. HRR of two boxes fire tests are higher than that of one box fire tests under fixed pressures. However, there are a higher peak of HRR under a fixed higher pressure for one-box fire tests while a lower peak of HRR under a higher pressure for two-box fire tests. The HRR would decrease sharply after reaching the peak.

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