• Journal of Advanced Marine Engineering and Technology
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• 제26권1호
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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 Advanced Marine Engineering and Technology
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• 제22권4호
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• pp.551-559
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• 1998

Evaporation and ignition characteristics of fuel droplet have major influences on the efficiency and performance of engine. In the present study the experiment of evaporation and self-ignition of single fuel was performed under the various ambient conditions. An individually suspended droplet of n-heptane n-hexadecane ethyl-alcohol and light oil were employed as a liquid droplet. Evaporation and ignition characteristics were measured by using the video-camera and image processing technique under the various ambient temperatures (up to 1000310 OC)and partial pressure of oxigen(up to 60%) The evaporation curve shows that the droplet life time ignition delay time decreases as the ambient temperature and partial pressure of oxigen increase, The temperature variations of droplet were also reported for various fuel and ambient temperatures. The numerical simulations were carried out to predict droplet diameter and temperature with favorable agreement.

• 대한기계학회논문집B
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• 제29권12호
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• pp.1360-1368
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• 2005

This study investigates the characteristics of spray, such as evaporation rate and spray trajectory, for a 4-hole injector which is applied to a 4-valve motorcycle gasoline engine. Three dimensional, unsteady, compressible flow and spray within the intake-port and cylinder have been simulated using the VECTIS code. Spray characteristics were investigated at 6000 rpm engine speed. Furthermore, we visualized fuel behavior in the intake-port using a CCD camera synchronized with a stroboscope in order to compare with the analytical results. Boundary and intial conditions were employed by complete 1-D simulation of the engine using the WAVE code. Fuel was injected into the intake-port at two time intervals relative to the position of the intake valves so that the spray arrived when the valves were closed and fully open. The results showed that the trajectory of the spray was directed towards the lower wall of the port with injection against the closed valves. With open valve injection, a large portion of the fuel was lifted by the co-flowing air towards the upper half of the port and this was confirmed by simulation and visualization.

• 동력기계공학회지
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• 제3권3호
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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.

• 한국분무공학회지
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• 제11권3호
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• pp.140-146
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• 2006

The objective of this work is to analyze the atomization and evaporation characteristics of dimethyl ether(DME) fuel for the application of HCCI diesel engine. In order to investigate the spray behavior of DME fuel, the macroscopic and microscopic characteristics were investigated in terms of spray development, spray tip penetration, impingement time, SMD, and axial mean velocity under the various injection timing and ambient conditions. For the illumination of spray, the spray visualization system was composed of a Nd:YAG laser and an ICCD camera and laser-sheet method was used. The atomization characteristics of DME fuel are analyzed by using phase Doppler particle analyzer (PDPA) system It was reveal that the spray development of DME is slower and rapidly disappeared as elapsed time after start of injection at the same injection duration. The impingement timing of diesel fuel was fester than that of DME fuel. The comparison of spray atomization characteristics in both fuels shows that diesel fuel has a large SMD value that DME.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.269-272
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• 2005

Due to the high density and heating value, liquid fuel is attractive for ramjet propulsion system. Liquid fuel requires time to evaporation and mix with incoming air before ignition; insufficient evaporation and mixing result in low combustion efficiency and instability. So the numerical studies are conducted to investigate the spray and combustion characteristics of a liquid-fueled dump type Integrated Rocket Ramjet combustor. The governing equations are solved by means of a finite-volume using time derivative preconditioning method for chemical reacting flow. The liquid phase is treated by solving Lagrangian equations of motion and transport for the life histories of a statistically significant sample of individual droplets.

• 수산해양기술연구
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• 제28권4호
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• pp.418-429
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• 1992

Recently, many researchers make a great effort to develop high efficient marine diesel engines using low grade heavy oil, and also study substitution fuel oil for engines and boilers. In case of Fisheries Vessels, we need to know that fish oil can be substituted for fuel oil. Therefore, it is studied that evaporation, ignition and combustion phenomena of the single droplet of fish oils (i.e., Sardine fish oil, File fish oil and Alaska pollac oil) on heated plane surface to evaluate appropriateness as substitution oil. Methanol and light oil are tested simultaneously to help the evaluation on these Fish oils. The results are summarized as follows: 1. The type of evaporation and combustion is spherical evaporation in case of methanol and light oil. And fish oil blended with light oil was finished after spherical evaporation happen when high temperature. 2. Ignition of Pure fish oil was shorter than that of fish oil blended with light oil. 3. Heat transferred to droplet could make qualitative comparison by contact diameter of droplet with hot surface as time changes. Life time of droplet according to the change of heated surface temperature was greatly influenced by droplet contact condition on the heated surface. 4. As far as combustion phenomena was concerned, apparent diameter of the fish oil droplet increased after ignition and decreased suddenly by internal boiling of droplet. 5. Three fish oils had similar phenomena on the evaporation, ignition and combustion. 6. Evaporation and combustion feature of fish oil could not be shown by coefficient of evaporation velocity of droplet and coefficient of combustion velocity of droplet.

• 대한기계학회논문집
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• 제17권5호
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• pp.1246-1252
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• 1993

본 연구에서는 CWS액적을 대상으로 주위 분위기 조건등에 대하여 점화등의 연소현상을 평가하기 위한 실험장치를 구성하고 일련의 실험을 수행하였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.218-222
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• 2006

Due to the high density and heating value, liquid fuel is attractive for ramjet propulsion system. Liquid fuel requires time to evaporation and mix with incoming air before ignition; insufficient evaporation and mixing result in low combustion efficiency and instability. So the numerical studies are conducted to investigate the spray and combustion characteristics of a liquid-fueled dump type Ramjet combustor. The governing equations are solved by means of a finite-volume using time derivative preconditioning method for chemical reacting flow. The liquid phase is treated by solving Lagrangian equations of motion and transport for the life histories of a statistically significant sample of individual droplets.

• 한국항공우주학회지
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• 제34권7호
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• pp.89-96
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• 2006

액체 로켓의 가스발생기의 연소 온도는 터빈 깃의 열 손상을 방지하기 위하여 1,000K 이하로 유지되며 이를 위하여 농후 연소 또는 산화제 과다 연소를 유지한다. 이러한 이유로 연소는 비평형 화학반응이 주로 발생하며 연소반응을 예측하기가 매우 어렵다. 한편 케로신은 여러 가지 탄화수소 연료로 이루어진 혼합연료로 화학반응 메커니즘에 대한 모델이 매우 어려운 실정이다. 본 연구에서는 Dagaut가 개발한 207 화학종, 1592 화학반응 단계를 이용하였으며 완전혼합반응기 연소모델을 적용하여 계산하였다. 계산결과와 실험결과를 비교하여 보면 사용된 화학반응 기구가 검댕 예측을 하지 않고 있음에도 불구하고 계산 결과는 연소가스 온도 뿐 아니라 가스 물성치 등을 매우 잘 예측하고 있음을 확인하였다.