• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.107-115
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• 1999

Hydrocarbon emission from spark ignition engines deeply relates with fuel evaporation mechanism. Therefore, fuel evaporation on the back of the intake valve is very important to understand fuel evaporation mechanism during engine warm up period. Intake valve heat transfer model was build up to estimate the amount of fuel evaporation on the intake valve back . Intake valve temperature was measured intake valve temperature is increased rapidly during few seconds right after engine start up and it takes an important role on fuel evaporation. The liquid fuel evaporation rate on the intake valve back proportionally increases as valve temperature increases, however its contribution slightly decreases as intake port wall temperature increases. The fuel evaporation rate on the valve back is about 40∼60% during engine warm-up period and it becomes about 20∼30% as intake port wall temperature increases. The estimation model also makes possible model also makes possible to review the effect of valve design parameters such as the valve mass and seat area on fuel evaporation rate through intake valve heat transfer.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.2125-2131
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• 1991

Evaporation rate constant, obtained by in this experimental study, of freely falling liquid fuel droplet on the condition of hot and pressurized environment are converted to critical evaporation constant according to Eq. of Ranz and Marshall. Critical evaporation constant, on constant environment pressuire, actively increase almost linearly with environment temperature increasing, but, on constant temperature, increases more or less with pressure increasing. Multycomponent droplet mixed with the fine fuel having a different of boiling point evaporate in order to boiling point, and each evaporation rate constant of mixed fuel equal to each fuel.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.132-137
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• 2002

Recently, impinging spray is used for atomization of diesel engine, but it bring on adhesion of fuel. Therefore, we studied about droplet behavior on high temperature plate changing the size of droplet, surface temperatures, and surface roughness of plate. In this study, We studied to confirm experimentally about mechanism of evaporation and ignition process of single fuel droplet. We observed evaporation time, evaporation appearance and ignition delay time by the photopraphs of 8mm video camera. Experimental results are summarized as follows: 1. The boiling point of fuel affect a evaporation and ignition process. 2. The surface roughness affect a evaporation time. 3. The ignition delay time relate to evaporation characteristic.

• Journal of ILASS-Korea
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• v.2 no.2
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• pp.24-34
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• 1997

This paper describes the investigation of combustion characteristics of gasoline-methanol blend in constant volume combustion chamber. A constant volume combustion chamber was used to elucidate a basic combustion characteristics and the premixer was installed to control temperature and equivalence ratio. And the maximum pressure, combustion duration and flame propagation according to the evaporation rate were measured to determine the optimal temperature range for evaporating a blend fuel. These experimental results indicate that the combustion characteristics such as combustion chamber pressure and combustion were deteriorated by decreasing surrounding temperature of fuel. These experimental results indicate that the combustion characteristics such as combustion chamber pressure and combustion were deter orated by decreasing surrounding temperature of fuel injected. It was also found that the overall gasification process for methanol blend fuel was influenced by a combustion chamber temperature rather than a premixer temperature.

• Journal of ILASS-Korea
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• v.1 no.3
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• pp.29-36
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• 1996

The present study systematically investigates the effect of evaporation rate on the combustion characteristics and the flame stabilization in a gasoline engine. A constant volume combustion chamber was used to elucidate a basic combustion characteristics and the premixer was installed to control temperature and equivalence ratio. And the maximum pressure, combustion duration and flame propagation according to the evaporation rate were measured to determine the optimal temperature range for evaparating a gasoline fuel. These experimental results indicate that the combustion characteristics such as combustion chamber pressure and combustion duration were deteriorated by decreasing surrounding temperature of fuel injected. It was also found that the overall gasification process for gasoline fuel was strongly influenced by a combustion chamber temperature rather than a premixer temperature.

• Journal of ILASS-Korea
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• v.26 no.2
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• pp.73-80
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• 2021

Evaporation characteristics of single butanol gel fuel were investigated in different mass ratios of gellant and ambient temperatures. Gel fuel was made by adding the pure water and hydroxypropylmethyl cellulose (HPMC) into the 1-butanol. Increase of viscosity was observed when the loading of HPMC increased. The evaporation process of gel droplet could be divided into three stages: droplet heating, micro-explosion and crust formation. Elevation of ambient temperature helped boost the evaporation in all experimental cases, but the effect was mitigated when the mass ratio of HPMC increased. Increase of HPMC weight ratio reduced the evaporation rate.

• Journal of the Korean Society of Combustion
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• v.21 no.2
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• pp.7-14
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• 2016

Evaporation and combustion characteristics of fuel droplet with carbon nanoparticle were investigated in a rapid compression machine(RCM). RCM is an experimental equipment to simulate one compression stroke of reciprocating engine. Nitrogen was charged into reaction chamber for evaporation experiment, while oxygen was charged for combustion experiment. N990 carbon black and n-heptane were used to synthesize the carbon nanofluids. Surfactant, span80, was used to make synthesis easier. The droplet pictures were taken using a high speed camera with 500 frames per second. Thermocouple, of which tip is $50{\mu}m$, was used not only to measure transient bulk temperature, but also to suspend the droplet. Reaction chamber temperature was calculated from pressure data. The evaporation rate of nanofluids was improved compared to pure fuel. The ignition delay was promoted due to the nanoparticle, but the burning rate was decreased.

• Journal of Power System Engineering
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• v.3 no.3
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• pp.36-43
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• 1999

Many of thermodynamic-based diesel combustion simulations incorporated a model of fuel spray which attempts to describe how the spray develops according to time. Because the spray geometry is an essential aspect of the fuel-air mixing process, it is necessary to be calculated quantitatively for the purpose of heat release and emission analysis. In this paper, we proposed the calculating method of non-evaporation spray behaviors by injection rate shapes under actual operating conditions of diesel engine. We confirmed the utility of this calculating model as the calculated results were compared with the measured results. This calculating program can be applied usefully to study on the diesel spray behavior.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.3
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• pp.53-60
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• 2002

This paper presents the results of the experimental investigation on the effect of acoustic wave on the combustion of suspended A-1 jet fuel droplets in atmospheric pressure. Experimental results indicate that A-1 jet fuel droplet burning rate constants $k_c$ were independent of initial droplet size and the relative evaporation/burning-rate constant $k_{e'}k_c$(ratio of the acoustically disturbed evaporation/burning-rate constant to the undisturbed evaporation/burning-rate constant) increased remarkably 1.2~1.51times, 1.04~1.42times, for frequency below 100Hz, and sound pressure level above 80dB.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.579-582
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• 2012

Removing residual water in a fuel cell is a critical operational process for managing its performance and controlling its lifetime. Understanding the mechanism of water transport in fuel cells is essential for the design of the water removal process. In this study, an experimental method for measuring the water evaporation rate through a gas diffusion layer, which is a porous medium, under steady-state conditions was developed. Experimental bench tests were conducted to apply the developed method. Then, the effects of various parameters of the drying gas and the gas diffusion layer were experimentally measured. The water evaporation rate increased as the humidity of the drying gas decreased and the flow rate of the drying gas increased. In addition, a thinner gas diffusion layer yielded a higher water evaporation rate.