Auto-Ignition Characteristics of Single<i>n</i>-Heptane Droplet in a Rapid Compression Machine

Kim, Hye Min; Baek, Seung Wook; Chang, Daejun

doi:10.1080/00102202.2014.890598

Cited by 17 publications

(6 citation statements)

References 23 publications

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“…The physical delay time is caused by the evaporation of fuel droplets, diffusion, and mixing with the surrounding air. The chemical ignition delay time is caused by the slow oxidation of fuel vapor and air to the occurrence of severe combustion 20 . Moreover, the ignition of the droplet of nanofluid fuels is also affected by the concentration of combustible vapor around the droplet.…”

Section: Resultsmentioning

confidence: 99%

“…The chemical ignition delay time is caused by the slow oxidation of fuel vapor and air to the occurrence of severe combustion. 20 Moreover, the ignition of the droplet of nanofluid fuels is also affected by the concentration of combustible vapor around the droplet. The evaporation amount of the double droplets of nanofluid fuels before ignition is greater than that of the single droplet.…”

Section: Ignition Delay Time Of Nanofluid Fuel Dropletsmentioning

confidence: 99%

“…In fact, the light blue flame observed at the bottom of the droplet is due to the relatively low-temperature chemical reaction of the vapor after a physical delay time. 20 The vapor is subjected to gravity and buoyancy at the same time. Before the droplets are ignited, the combustible vapor contains a large amount of n-heptane vapor, which is more affected by gravity than buoyancy due to the difference in density.…”

Section: Ignition Delay Time Of Nanofluid Fuel Dropletsmentioning

confidence: 99%

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Effect of double‐droplet interaction on ignition and combustion characteristics of heptane‐based nanofluid fuels in a high‐temperature environment

Zhu

Wang

Dai

et al. 2022

Env Prog and Sustain Energy

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The ignition and combustion characteristics of a single droplet or double droplets of the Al/n‐heptane‐based nanofluid fuels with different arrangements were investigated by a droplet‐suspension method at high temperature. The addition of ricinoleic acid and nano‐sized Al particles to n‐heptane can improve the ignition performance of n‐heptane droplets, and the ignition delay times of n‐heptane droplets are decreased by the maximum of 19.0% and 31.0%, respectively. The mixing effect of combustible vapor of adjacent droplets and the heat transfer effect of adjacent flames are responsible for the different combustion processes of nanofluid fuel droplets with different arrangements. Compared with the single droplet, the ignition delay times of the horizontal and vertical double droplets are decreased by the maximum of 26.9% and 45.7%, respectively. The vertical double droplets have better ignition performance than the horizontal double droplets due to the disturbance and mixing of the vapor flow with different directions. In addition, the droplet arrangement has different promotion effects on different droplets.

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Section: Resultsmentioning

confidence: 99%

Section: Ignition Delay Time Of Nanofluid Fuel Dropletsmentioning

confidence: 99%

Section: Ignition Delay Time Of Nanofluid Fuel Dropletsmentioning

confidence: 99%

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Effect of double‐droplet interaction on ignition and combustion characteristics of heptane‐based nanofluid fuels in a high‐temperature environment

Zhu

Wang

Dai

et al. 2022

Env Prog and Sustain Energy

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“…As evaporation occurs, the hexadecane-toluene mixture vapor diffuses into the hot ambient air. Image 4 shows the start ignition of the droplet. One of the primary characteristics of droplet ignition under high-pressure conditions is the Stefan flow of fuel vapor from the droplet surface that is slow due to the increase in boiling temperature and the decrease in diffusion coefficient . The ignition is followed by a steep increase in the temperature until it reaches its maximum, after which the flame started to diminish. Image 5 shows the condition where the flame has completely consumed all the oil-fuel mixture.…”

Section: Resultsmentioning

confidence: 99%

Auto-Ignition of a Hexadecane Droplet Mixed with Different Octane Number Fuels at Elevated Pressures To Investigate the Pre-Ignition Behavior

et al. 2019

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Pre-ignition is an abnormal combustion event that may occur in boosted direct injection gasoline engines, where one or more auto-ignition events are observed before spark ignition. Due to the direct injection of fuel into the cylinder, some liquid fuel may splash off the walls, pulling lubricating oil with it. The auto-ignition of liquid fuel/lubricant droplets is considered as one of the possible sources of pre-ignition. To assess this stochastic phenomenon in a controlled way, the autoignition of a single droplet of a hexadecane-fuel mixture was investigated, with hexadecane serving as a surrogate for the lubricating oil. This experiment included suspending a single hexadecane-fuel mixture droplet on a thermocouple bead in preheated air, at a temperature of 300 ± 4°C, in a constant volume chamber over a wide range of pressures (4−30 bar). Four different fuels with a range of research octane number (RON) between 70 and 120 were mixed with hexadecane at a volume percentage of 75% hexadecane to 25% fuel to investigate the time to ignition of the droplet, designated as TI. The TI was measured by recording the droplet temperature history simultaneously with high-speed droplet imaging. The droplet ignition is triggered by the auto-ignition of the combustible mixture formed by the hexadecane-fuel mixture's vapor that mixes with the hot ambient air around the droplet. An empirical model was proposed to predict the TI in terms of pressure and the mixture's RON.At constant pressure, the rate of evaporation of the mixture's droplet increases with increasing RON. The time to ignition is seen to increase exponentially as the fuel's RON used in the mixture increases. On the other hand, for a given fuel RON, the time to ignition decreases with increasing ambient pressure. The empirical model shows that at pressures above 20 bar, the dilution of hexadecane by the different fuels has no significant effect on delaying the auto-ignition of the droplet.

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“…Droplet evaporation and combustion were recorded by a high-speed camera (200 frames/s). Changes in droplet diameter were analyzed using Visual Basic software, as described previously [24,25]. Ambient temperature was controlled in the range 400-700 • C at intervals of 100 • C, with consideration of the boiling and autoignition points of diesel given as manufacturer (Table 1).…”

Section: Viscosity Measurementsmentioning

confidence: 99%

The Viscosity and Combustion Characteristics of Single-Droplet Water-Diesel Emulsion

et al. 2019

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Diesel fuel exhibits excellent combustion characteristics and stability. However, diesel use is becoming restricted because of its associated environmental problems. Fuel emulsification, which increases efficiency and reduces pollution, became the solution of environmental problem. In this study, five water:diesel emulsions with mass ratios (0.3, 0.6, 1.0, 1.2, and 1.5) via ultrasonication were synthesized with and without surfactant. The optimal water:diesel ratio (=1:1) of an emulsion containing the surfactant was found by analyzing fuel concentration, mixing time, and viscosity. The combustion characteristics of single-droplet optimal emulsions were studied through ignition delay, burning rate, and total droplet lifetime at high temperature (400–700 °C) and pressure (1–15 bar), and micro-explosion phenomenon was observed. Although the ignition delay of emulsion increased, the total lifetime of the emulsion droplet was lower than that of diesel under 5 bar, 600 °C condition.

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Auto-Ignition Characteristics of Singlen-Heptane Droplet in a Rapid Compression Machine

Cited by 17 publications

References 23 publications

Effect of double‐droplet interaction on ignition and combustion characteristics of heptane‐based nanofluid fuels in a high‐temperature environment

Effect of double‐droplet interaction on ignition and combustion characteristics of heptane‐based nanofluid fuels in a high‐temperature environment

Auto-Ignition of a Hexadecane Droplet Mixed with Different Octane Number Fuels at Elevated Pressures To Investigate the Pre-Ignition Behavior

The Viscosity and Combustion Characteristics of Single-Droplet Water-Diesel Emulsion

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