Inition Phenomenon of a Fuel-droplet Impinging upon a Hot Surface

Karasawa, Takao; Shiga, Seiichi; Kurabayashi, Toshio

doi:10.1299/jsme1958.29.143

Cited by 7 publications

(3 citation statements)

References 2 publications

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“…This leads to the formation of a thin layer of vapor, indicating the onset of the film boiling stage. Figure 3 illustrates the film boiling phenomenon, with the change in diesel leakage on the hot surface at 2674.5 ms. h F at this stage is calculated using Equation ( 8) [43] for the heat transfer coefficient.…”

Section: Effect Of Edge Structure On Diesel Hsi Position With Varying...mentioning

confidence: 99%

Influence of Edge-Limited Hot Surfaces on Accidental Ignition and Combustion in Ship Engine Rooms: A Case Study of Marine Diesel Leakage

Liu,

Wang,

et al. 2024

JMSE

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To extend initial ignition-related fire prevention in ship engine room, this work presents a case study of marine diesel leakage for identifying accidental ignition by hot surface. Based on a self-designed experimental platform, a full-scale innovative experimental arrangement was conducted for diesel leakage-related hot surface ignition (HSI) tests in a ship engine room. A series of parameters (e.g., heat transfer, evaporation mode, ignition position, ignition delay time, flame instability, and combustion behavior) for improving the initial HSI of diesel leakage on an edge-limited hot surface were analyzed. A transient sequence corresponding to a change in leakage flow rates ranging from 7.5 mL to 25 mL was tested, and hot surface temperatures (HSTs) were adjusted between 390 °C to 525 °C. Puffing motion accelerated the mixing of HSI-driven vapors with fresh air, which was affected by the edge-based limitation and HSTs. The case study identified the effects of hot surface shape and the most important combinations of HSI-driven combustion characteristics for estimating initial ignition responses. Based on this current work, prediction models were proposed for determining the HSI height of marine diesel for varying leakage flow rates and HSTs. The results indicate that HSI height increases with leakage flow rate and HSI position is influenced by edged hot surfaces, leading the vertical centerline to shift towards the side of the edge structure. The results also revealed that the ignition delay time of diesel leaked onto an edged hot surface decreases as leakage flow rate increases. This change causes the initial HSI to occur earlier, potentially creating an extra risk in ship engine rooms.

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Section: Effect Of Edge Structure On Diesel Hsi Position With Varying...mentioning

confidence: 99%

Influence of Edge-Limited Hot Surfaces on Accidental Ignition and Combustion in Ship Engine Rooms: A Case Study of Marine Diesel Leakage

Liu,

Wang,

et al. 2024

JMSE

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“…where ρ v is the density of fuel released into ambient air from the hot surface, kg/m 3 ; ρ l is the density of marine fuel, kg/m 3 ; λ v is the thermal conductivity of vapor in the film between the marine fuel and hot surface, W/(m•K); h v is the latent heat of vaporization, kJ/g; σ is the surface tension of marine fuel; and N/m; µ v is the viscosity of the vapor in the film between the surface and fuel, mm 2 /s. When marine fuel on a high-temperature surface is in a film boiling state, h f can be presented [35] as follows.…”

Section: Initial Position Of Hsi Occurrence With An Elevated Hot Surf...mentioning

confidence: 99%

Experimental Study on the Hot Surface Ignition Characteristics and a Predictive Model of Marine Diesel in a Ship Engine Room

Wang,

Qiu,

Ming

et al. 2024

JMSE

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To ensure the safe protection of marine engine systems, it is necessary to explore the hot surface ignition (HSI) characteristics of marine diesel in ship environments. However, an accurate model describing these complex characteristics is still not available. In this work, a new experimental method is proposed in order to enhance prediction performance by integrating testing data of the characteristics of HSI of marine diesel. The sensitivity of HSI is determined by various factors such as surface parameters, flow state, and the ship’s environment. According to variations in the HSI status of marine diesel in an engine room, the HSI probability is distributed in three phases. It is essential to determine whether the presence of marine diesel or surrounding items can intensify the risk of an initial fire beginning in the engine room. A vapor plume model was developed to describe the relationship between HSI height and initial specific buoyancy flux in vertical space. Further, field distribution revealed significant variation in the increase in temperature between 200 and 300 mm of vertical height, indicating a region of initial HSI. In addition, increasing surface temperature did not result in a significant change in ignition delay time. After reaching a temperature of 773 K, the ignition delay time remained around 0.48 s, regardless of how much the hot surface temperature increased. This study reveals the HSI evolution of marine diesel in a ship engine room and develops data-based predictive models for evaluating the safety of HSI parameters during initial accident assessments. The results show that the goodness of fit of the predictive models reached above 0.964. On the basis of the predicted results, the HSI characteristics of marine diesel in engine rooms could be gleaned by actively determining the parameters of risk.

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“…The evaporation and burning characteristics of a droplet which is near a hot solid surface are different than for a droplet in an unbounded ambience (Tamura & Tanasawa 1959; Gottfried et al 1966;Karasawa 1986Karasawa 1988. The flame shape, burning rate, and extent of sooting in particular are influenced by the proximity of the droplet to the surface.…”

Section: Introductionmentioning

confidence: 99%

Droplet combustion near a cold surface

Chandra

Avedisian

1990

Proc. R. Soc. Lond. A

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The combustion of a liquid droplet adjacent to a cold surface was studied experimentally. To isolate the effect of the proximity of the droplet to the surface, the ambient pressure (0.101 MPa), liquid composition ( n -heptane), initial liquid volume (7 x 10 -4 ml), surface material (quartz) and ambient temperature (20 ± 2°C) were held constant. A range of distances L from the surface were studied (1 mm < L < ∞). Both horizontal and vertical surface orientations were examined. A more limited set of experiments were carried out in a low gravity (i. e. low buoyancy) environment to provide a basis of comparison with relevant theoretical analyses. The flame shape, soot formation, fuel condensation, and droplet burning rate were all found to be strongly affected by the proximity of the droplet to the surface. For sufficiently large L the flame was observed to be closed around the droplet throughout burning. As L decreased, the flame was truncated. The droplet burning rate decreased as the droplet was brought progressively closer to the surface (in qualitative agreement with a relevant closed form potential flow solution to the analogous problem of a droplet burning adjacent to an adiabatic surface) and the burning rate of a droplet adjacent to a vertical surface was larger than for a horizontal surface. Surface orientation effects were observed to be absent for burning at low gravity. The extent of sooting as revealed by the flame colour was decreased, and fuel vapours condensed in a lens-like shape on the surface, as L was sufficiently reduced.

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Inition Phenomenon of a Fuel-droplet Impinging upon a Hot Surface

Cited by 7 publications

References 2 publications

Influence of Edge-Limited Hot Surfaces on Accidental Ignition and Combustion in Ship Engine Rooms: A Case Study of Marine Diesel Leakage

Influence of Edge-Limited Hot Surfaces on Accidental Ignition and Combustion in Ship Engine Rooms: A Case Study of Marine Diesel Leakage

Experimental Study on the Hot Surface Ignition Characteristics and a Predictive Model of Marine Diesel in a Ship Engine Room

Droplet combustion near a cold surface

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