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2021

Journal

Engineering

Progress in Scale Modeling, an International Journal

Articles 1 - 8 of 8

Full-Text Articles in Life Sciences

Open-Field Scale-Model Experiments Of Fire Whirls Over L-Shaped Line Fires, Yuto Iga, Kazunori Kuwana, Kozo Sekimoto, Yuji Nakamura Feb 2021

Open-Field Scale-Model Experiments Of Fire Whirls Over L-Shaped Line Fires, Yuto Iga, Kazunori Kuwana, Kozo Sekimoto, Yuji Nakamura

Progress in Scale Modeling, an International Journal

This paper presents the results of open-field scale-model experiments of fire-whirl formation over line fires. L-shaped line fires were burned in crosswinds, and the processes of fire-whirl formation were observed. The flame height was measured using an image-processing technique, while two-dimensional velocity components were measured at two different locations using ultrasonic anemometers. Two tests were selected for comparison: test A, in which intense fire whirls repeatedly formed, and test B, in which no whirls were observed. In test A, the wind flow was bent by the fire plume, creating swirling flows near the burning area, thereby forming fire whirls. On …

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Effect Of Reduced Plume Entrainment On The Burning Rate Of Porous Fuel Beds, Sara Mcallister Feb 2021

Effect Of Reduced Plume Entrainment On The Burning Rate Of Porous Fuel Beds, Sara Mcallister

Progress in Scale Modeling, an International Journal

Large outdoor fires often exhibit unexpected fire behavior, particularly compared with much smaller fires. Understanding the difference between large- and small-scale fires is of importance for both fire behavior predictions and safety. Large fires are often characterized by very tall plumes that can extend to the stratosphere. Particularly as the actively burning area increases, plumes in large-scale fires likely entrain relatively little and may act in a similar fashion to a chimney. To explore the possible changes in burning rate due to the chimney effect, experiments were conducted with wood cribs burned with a chimney of variable height. The burning …

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Scale Model Test To Estimate Thermal Damage By Fire In Aircraft Cargo, Jian Gao, Tsuneyoshi Matsuoka, Yuji Nakamura Feb 2021

Scale Model Test To Estimate Thermal Damage By Fire In Aircraft Cargo, Jian Gao, Tsuneyoshi Matsuoka, Yuji Nakamura

Progress in Scale Modeling, an International Journal

The Federal Aviation Administration (FAA) requires fire detectors to alarm within one minute of the start of a fire in cargo compartments of airplanes. To determine whether such alarm timing works, investigations of the thermal damage to ceilings and other structures during the early stage of a fire were accomplished to demonstrate compliance with these FAA regulations. The objective was to test the feasibility of predicting convective heat transfer in early stage of a cargo compartment fire by conducting reduced scale (lab scale) experiments. First, the scaling laws was derived and validated. Then, full-scale and half-scale experiments were performed with …

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Extinguishment Of Diffusion Flames Formed Over A Porous Plate Burner Using Rubber Balloons Filled With Inert Gases, Hiroyuki Torikai, Shinya Kudo Feb 2021

Extinguishment Of Diffusion Flames Formed Over A Porous Plate Burner Using Rubber Balloons Filled With Inert Gases, Hiroyuki Torikai, Shinya Kudo

Progress in Scale Modeling, an International Journal

We have proposed an inert gas, rubber-balloon extinguishing method which might increase the effectiveness of extinguishing flames and decreasing the amounts of agents needed for fire suppression. Hence, extinguishing experiments have been performed to further clarify possible extinguishing characteristics, mechanisms and scaling effects of this method. Carbon dioxide, nitrogen, argon and helium gases were used as the extinguishing agents. Methane-air and propane-air diffusion flames were formed on two different diameter, round porous plate burner and used as the targets for extinguishment. The extinguishing probabilities were measured, and the extinguishing processes were observed with a high-speed camera. As a result, an …

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Effects Of Dimensionless Numbers On Decomposition Of Methane Hydrate, Shoma Shimizu, Genichiro Kushida Feb 2021

Effects Of Dimensionless Numbers On Decomposition Of Methane Hydrate, Shoma Shimizu, Genichiro Kushida

Progress in Scale Modeling, an International Journal

It is necessary to elucidate the decomposition and combustion of methane hydrate for fire safety during transportation and storage to utilize it for commercial practice. The amount of methane evolved during the decomposition of methane hydrates is affected by the conditions such as the initial temperature, initial density and ambient temperature. In the present study, the internal temperature of methane hydrate and the amount of methane evolved during its decomposition were investigated by a dimensionless numerical analysis using a transient one-dimensional conduction model from a symmetrical methane hydrate ball heated by ambient air. The numerically calculated central temperature and the …

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A Study On Fire Hazards Of Oil Tanks In Urban Areas With Scale Model Experiments, Ho Yin Ng, Yu Wan, Wan Ki Chow Feb 2021

A Study On Fire Hazards Of Oil Tanks In Urban Areas With Scale Model Experiments, Ho Yin Ng, Yu Wan, Wan Ki Chow

Progress in Scale Modeling, an International Journal

Large fuel tanks are located in an urban area of Tsing Yi in Hong Kong, giving potentially high risks to people living nearby if a fire was to occur. Scale modeling experiments were carried out to investigate the potential of fire hazards. Propanol pool fires with five different scales of oil tanks were studied first. Appropriate tank sizes were then put in a 1/2500 architectural scale model on the Tsing Yi Island to study a fuel tank fire. Results show that the heat and smoke from a fire would affect occupants staying in areas near to the fuel tanks. Fire …

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Fingering Behavior Of Flame Spread Over Solid Combustibles, Tsuneyoshi Matsuoka, Kentaro Nakashima, Takuma Kajimoto, Akihiro Yoshimasa, Yuji Nakamura Feb 2021

Fingering Behavior Of Flame Spread Over Solid Combustibles, Tsuneyoshi Matsuoka, Kentaro Nakashima, Takuma Kajimoto, Akihiro Yoshimasa, Yuji Nakamura

Progress in Scale Modeling, an International Journal

In this study, the fingering pattern formation and the following flamelet spreading over three different kinds of thick combustibles, i.e., Poly methacrylate (PMMA), Poly ethylene (PE) and Poly carbonate (PC) were observed and the effective Lewis number correlation was validated. Experiments were performed with a narrow channel apparatus. In addition to the kinds of solid fuel materials, the channel height and the oxidizer velocity were varied as experimental parameters. An image analysis method was developed to quantify the number, diameter and spread rate of the flamelets. Replacing the fuel thickness into the thermal thickness, the effective Lewis number which is …

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Data-Driven Tools Guided By First-Principles For Scale Modeling, Sadegh Poozesh Jan 2021

Data-Driven Tools Guided By First-Principles For Scale Modeling, Sadegh Poozesh

Progress in Scale Modeling, an International Journal

For decades, traditional scale-modeling techniques have been relying on first-principles models (FPMs). FPMs have been used to find non-dimensional numbers (PIs) and identify normalized underlying forces and energies behind the phenomenon in focus. The two main challenges with FPM-based PIs extraction are finding the relevant PIs and proper correlations between PIs. The emergence and surge of data-driven modeling (DDM) provide a new opportunity to leverage experimental data in model development across scales/plants. In this paper, first, the two mentioned issues in PIs development will be elaborated to reveal the gap, and second, a new insight into scale modeling and similarity …

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