Experimental Investigation and Scaling Analysis of Turbulent Diffusion Flame Behavior over Inclined Surfaces Under Cross-Slope Wind

An experimental study and mathematical quantification of buoyant turbulent flame morphology under the coupling effects of inclined surfaces and crossflows

Flame morphologic characteristics of horizontally oriented jet fires impinging on a vertical plate: Experiments and theoretical analysis

Impact of ventilated tunnels on smoke peculiarities in train carriage fires with multiple lateral openings

The combustion of liquid fuels that have leaked into inert porous media, such as sand, is a critical issue for industrial safety and fire risk assessment. Despite its importance, the complex influence of porous media on the combustion process, particularly the governing mechanisms of flame morphology and heat release, remains poorly understood, hindering accurate hazard prediction. This study addresses this gap by systematically investigating the combustion characteristics of 92# gasoline on quartz sand substrates with thicknesses ranging from 0 to 4 cm. Through a series of controlled laboratory experiments, key parameters including mass loss rate, heat release rate (HRR), and flame morphology were quantified. The findings reveal that, unlike the classical three-stage combustion of pool fires, the presence of porous media introduces a “slow burning period,” resulting in a unique four-stage combustion mode. The sand layer significantly suppresses combustion intensity, with the dimensionless heat release rate (Q*) being proportional to the dimensionless layer thickness (d*) raised to the power of −2.54. Crucially, flame height was found to be governed not by the HRR, but by a competition between the capillary effect (driving upward fuel transport) and the thermal effect (insulation and heat absorption). Based on this mechanism, a novel flame height prediction model was developed, which showed excellent agreement with 23 experimental datasets (R2 = 0.92, average relative error 1.72%). This study elucidates the core physical mechanisms governing liquid fuel combustion in porous media. The proposed model provides a robust theoretical foundation for predicting fire development and assessing the risks associated with leaked fuel fires, offering a valuable tool for safety engineering and emergency response.

Experimental research on the flow field and flame geometry of free buoyant diffusion flames with low dimensionless heat release rates

An investigation of the detailed flame shape and flame length under the ceiling of a channel

Characterization of ceiling smoke temperature profile and maximum temperature rise induced by double fires in a natural ventilation tunnel

Concave surface is a common geometry in both industrial buildings and natural environments; the flame spread behaviors on this special surface are worth studying, while few studies have been completed yet. In this study, kraft paper, which is a typical charring material, was chosen to investigate the behaviors of concurrent flame spread on concave surfaces. The results showed that there were three stages of the flame spread process on a concave surface: the flame gathering stage, the flame acceleration stage and the flame burnout stage. A peak mass loss rate was found at the end of the flame acceleration stage and then decayed rapidly due to the lack of sample that can maintain the flame spread. An experiential equation to predict the maximum mass loss rate was established. The flame spread showed an obvious acceleration with the increase in curvature, a new dimensionless number was proposed to find out whether the flame spread was accelerated or not. For the accelerated flame spread, the critical value is 0.85. Segmented expressions between dimensionless flame height and dimensionless heat release rate were developed, with good correlation for smaller curvatures. This study’s results will fill the blank of flame propagation on concave surfaces, improve the understanding of fires in special cases, and provide assistance in related fire risk evaluations.

An experimental study of jet fires in pits

The intensity of solar radiation received by the PV Module can be maximized by installing a PV module with a slope angle. Besides, when the intensity of solar radiation increases, the surface temperature of PV also tends to increase, which decrease PV power output. Temperature Surface can also be reduced by the additional glazing with low emissivity. By knowing the appropriate angle of inclination and the glazing addition, it will able to maximize light energy (photon) and minimize heat energy received by PV surface. So the system can obtained maximum output power and minimum surface temperature. The heat transfer can be determined by analyzing the thermal resistance occurring from the sun down to the PV surface and from the PV surface to the surroundings. The test was performed using a commercial PV module with 180 Watt Peak power, where the test results were discussed and presented. The results shown that PV module facing North with slope angle 30° has the highest output power. The heat release was large enough compared to the other slope angle variation. Besides, the addition of glazing system decreases the output power due to its medium transmittance about 70% and the temperature of PV module also decrease due to low emissivity about 0.26.

An experimental study and analysis on maximum horizontal extents of buoyant turbulent diffusion flames subject to relative strong cross flows

Theoretical and numerical study on critical velocity and driving force for preventing smoke backlayering in a connection roadway fire of coal mines

Le Sentir. Vers une ontologie des œuvres d'art. À propos de... « Le psychopathologique et le Sentir. Nietzsche et les micro-incarnations » d'A. Fernandez-Zoïla,

In this study, a series of numerical simulations were carried out to investigate the effect of fire shutter descending height on the smoke extraction efficiency in a large space atrium. Based on the full-scale fire experiments, this paper carried out more numerical simulations to explore factors affecting the smoke extraction efficiency in the atrium. The smoke flow characteristics, temperature distribution law and smoke extraction efficiency of natural and mechanical smoke exhaust systems were discussed under different heat release rates and fire shutter descending heights. The results show that the smoke spread rate and the average temperature of the smoke are higher with a greater heat release rate. After the mechanical smoke exhaust system is activated, the smoke layer thickness and smoke temperature decrease, and the stable period of heat release rate is shorter. In the condition of natural smoke exhaust, the smoke extraction efficiency increases exponentially with the increase of heat release rate and the descending height of the fire shutter, and the maximum smoke extraction efficiency is 48.8%. In the condition of mechanical smoke exhaust, the smoke extraction efficiency increases with the increase of mechanical exhaust velocity. When the velocity increases to the critical value (8 m/s), the smoke extraction efficiency is essentially stable. The smoke extraction efficiency is increased first with the increase of fire shutter descending height and then has a downward trend when the descending height drops to half, and the maximum smoke extraction efficiency is 70.3% in the condition of mechanical smoke exhaust. Empirical correlations between the smoke extraction efficiency and the dimensionless fire shutter descending height, the dimensionless heat release rate and the dimensionless smoke exhaust velocity have been established. The results of this study can provide a reference for the design of smoke prevention and exhaust systems in the atrium.

Effects of crosswind and burner aspect ratio on flame characteristics and flame base drag length of diffusion flames