The rate of burning of fires in enclosures is usually assumed to be proportional to the ventilation factor A f i. This paper reports an experimental program designed to investigate the influence of opening width and enclosure shape on the burning rate by comparing the burning rate and behaviour of fires in long enclosures and wide enclosures with similar openings. Fire tests were conducted in enclosures 1500 mm by 600 mm by 300 mm high with ventilation openings of several widths. It was found that the burning behaviour and fuel mass loss rates of fires in long and wide enclosures differ markedly when the width of the ventilation opening is less than the full width of the enclosure. When the ventilation opening width is equal to that of the enclosure, the flows within the enclosure are essentially two dimensional, but when the opening width is less than that of the enclosure the flows within the enclosure are more complex and three dimensional. The mass loss rates for the same opening sizes in wide enclosures were found to be substantially greater than those in long enclosures for both full width (in the long enclosure) and partial width openings.
Results from an experimental program undertaken to study the effect of fuel quantity and location on ethanol pool fires in the open and in a small enclosure (an ISO 9705 room) are compared with simulations using the Fire Dynamics Simulator version 4.03 (FDS4). The fuel in trays is placed at three locations (front, back, and center) within the room enclosure as well as directly under the calorimeter hood. The measured heat release rate (HRR) is found to vary substantially when a fuel package consisting of different quantities of ethanol is placed at different locations within the room. Instead of prescribing this HRR into the FDS simulation, these experimental results are compared with HRR predictions obtained using the FDS4 combustion model. The comparison reveals that there are significant and variable differences between the experimental results and the FDS4 predictions in contrast to simulations where the HRR is prescribed.KEY WORDS: burning rate, heat release rate, pool fire, ISO 9705 room, fuel location, grid size.
In recent decades, several studies have considered the use of plastic waste as a partial substitute for aggregate in green concrete. Such concrete has been limited to non-structural applications due to its low strength. This raises whether such concrete can be enhanced for use in some structural applications. This paper reports an attempt to develop a structural-grade concrete containing plastic waste aggregate with high proportions of substitution and confined with carbon fiber reinforced polymer (CFRP) fabrics. Experimental research was conducted involving the casting and testing 54 plain and confined concrete cylinders. A concrete mixture was designed in which the fine aggregate was partially replaced by polyethylene terephthalate (PET) waste plastic at ratios of 0%, 25%, and 50%, and with different w/c ratios of 0.40, 0.45, and 0.55. The results show that confinement has a substantial positive effect on the compressive behavior of PET concrete. The enhancement efficiency increases by 8–190%, with higher enhancement levels for higher substitution ratios. Adding one layer of CFRP fabric raises the ultimate strength of samples that have lost compressive strength to a level close to that of unconfined samples not containing PET. This confinement is accompanied by an increase in the slope of the stress-strain curve and greater axial and lateral strain values at failure. For the specimens confined by CFRP fabric, PET aggregate can be used as a partial substitute for sand at a replacement ratio of up to 50% by volume for structural applications. This paper also considers the ability of existing models to predict the strength of confined-PET concrete circular cross-sections by comparing model predictions with experimental results. The strength of confined PET concrete elements can’t be accurately predicted by any of the models that are already out there. It’s important to come up with a new model for these elements.
The behaviour of fire within a deep (high depth to height ratio) enclosure with various openings in one end has been studied experimentally and by simulation (using FDS4). Sixteen fuel-trays were placed within an 8.0 m long x 2.0 m wide x 0.6 m high steel enclosure. The experiments confirmed previous smaller scale experiments, showed that the fires in deep enclosures are strongly influenced by the ventilation and are not at all uniform through the depth of the enclosure. The severity of exposure of structural members is much more severe near the ceiling near the front of the enclosure compared with the back of the enclosure. Depending on the criterion used the severity at the front may be from twice to five times as severe as at the back of the enclosure. The movement of the flame-front in the FDS4 simulation is similar to that found experimentally, but the predicted timing of flame-front movement and predicted HRR varies considerably from the experimental values.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.