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권지원 ( J. W Kwon ),정명철 ( M. C Jeong ),이진욱 ( J. W Lee ) 한국분무공학회 2013 한국액체미립화학회지 Vol.18 No.2
In this paper, high-pressure injection chatacteristics of servo hydraulic injector as the key component of diesel CRDi system, which is driven by solenoid and piezo-actuator were examined by experimental analysis. High-pressure injection characteristic of standard diesel fuel injected at high pressure up to 160 MPa was investigated at high-pressure chamber by using a high speed camera for spray visualization and quantitative analysis. By this study, we found that the piezo-driven injector has better performances in controlling the fuel injection with the high pressure, including fuel quantity, spray penetration length and spray velocity, than that of a solenoid-dricen injector. In particulat. The needle response time for start of injection in piezo-dricen injector was faster of about 125 μs than that of solenoid-driven injector. Consequently, it is known that the piezo-driven injector has more degress of freedom in controllong the fuel injection with the high pressure than solenoid-driven injector.
김재호 ( K. J. Kim ),임정현 ( J. H. Rhim ),노수영 ( S. Y. No ),문병수 ( B. S. Moon ),김주영 ( J. Y. Kim ),강경균 ( K. G. Kang ) 한국분무공학회 1999 한국액체미립화학회지 Vol.4 No.4
Spray angle, a parameter which is most commonly used to evaluate. spray distribution, is important because it affects the axial and radial distribution of the fuel. Spray angles were measured and compared for the pintle-type gasoline fuel injector with n-heptane as a test fuel with the three different measuring techniques, i.e. digital image processing, shadowgraphy and spray patternator, respectively. Fuel was injected with the injection pressures of 0.2-0.35MPa into the room temperature and atmospheric pressure environment. In digital image processing method, the transmittance level greatly influences the spray angle with the axial distance from the injector. From the experimental results by the shadowgraphy technique, it is obvious that the spray angle vary during the injection period. The results of spray angle from the spray patternator show that there exist the different spray angles in the different areas. The spray angles increase with the increase in the injection pressure for the three measurement techniques considered in this study. The spray angle is widely different, especially in the near region from the injector, according to the measurement techniques used in this experimental work.
정적연소기에서 분위기 압력에 따른 Diesel-DME 혼합연료의 분무 특성에 관한 연구
양지웅 ( Ji Woong Yang ),이세준 ( Se Jun Lee ),임옥택 ( Ock Taeck Lim ) 한국분무공학회 2012 한국액체미립화학회지 Vol.17 No.4
The aim of this study was to compare the spray characteristics of a typical fuel (100% diesel, DME) and diesel-DME blended fuel in a constant volume combustion chamber (CVCC). The typical fuel (100% diesel, DME) and diesel-DME blended fuel spray characteristics were investigated at various ambient pressures (pressurized nitrogen) and fuel injection pressures using a common rail fuel injection system when the fuel mixture ratio was varied. The fuel injection quantity and spray characteristics were measured including spray shape, penetration length, and spray angle. Common types of injectors were used.
분사조건에 따른 가솔린 직접분사용 다공 분사기에서의 LPG 분무특성
( Jin Young Jung ),( Hee Chang Oh ),( Choongsik Bae ) 한국분무공학회 2014 한국액체미립화학회지 Vol.19 No.1
Liquefied petroleum gas (LPG) is regarded as an alternative fuel for spark ignition engine due to similar or even higher octane number. In addition, LPG has better fuel characteristics including high vaporization characteristic and low carbon/ hydrogen ratio leading to a reduction in carbon dioxide emission. Recently, development of LPG direct injection system started to improve performance of vehicles fuelled with LPG. However, spray characteristics of LPG were not well understood, which is should be known to develop injector for LPG direct injection engines. In this study, effects of operation condition including ambient pressure, temperature, and injection pressure on spray properties of n-butane were evaluated and compared to gasoline in a multi-hole injector. As general characteristics of both fuels, spray penetration becomes smaller with an increase of ambient pressure as well as a reduction in the injection pressure. However, it is found that evaporation of nbutane was faster compared to gasoline under all experimental condition. As a result, spray penetration of n-butane was shorter than that of gasoline. This result was due to higher vapor pressure and lower boiling point of n-butane. On the other hand, spray angle of both fuels do not vary much except under high ambient temperature conditions. Furthermore, spray shape of n-butane spray becomes completely different from that of gasoline at high ambient temperature conditions due to flash boiling of n-butane
노즐 홀 직경에 따른 단공 GDI 인젝터의 분무 특성 연구 - (2) 분무 균일도 및 미립화 특성 비교
박정현 ( Jeonghyun Park ),노승천 ( Seungcheon Ro ),상몽소 ( Mengzhao Chang ),박수한 ( Suhan Park ) 한국분무공학회 2020 한국액체미립화학회지 Vol.25 No.4
A single spray plume is the basic unit of the entire spray plume and is an important factor in understanding the spray characteristics. However, since the multi-hole GDI injector has a narrow spray angle, the superposition of the spray plumes occurs severely. Therefore, the spray uniformity and the spray atomization characteristics of a single spray plume were analyzed in this study using a single-hole GDI injector. Five single-hole GDI injectors with different nozzle hole diameters were used in the experiment. The uniformity of the spray was evaluated through the analysis of the spray pattern images. In addition, the atomization characteristics were compared using the diameter distribution of the spray droplets obtained using PDPA. As a result, the larger diameter of the nozzle hole, the less uniformity of the spray, and the injection pressure did not have a significant effect on the spray uniformity. It is judged that the surface roughness of the injector has a greater effect on spray uniformity than the diameter of the nozzle hole. Also, the size of the spray droplets increased sharply when the diameter of the nozzle hole was 230 μm.
분무 가시화를 통한 직분사 시스템에서 n-heptane및 propane의 분무발달특성 비교
박준규,박성욱 한국분무공학회 2023 한국액체미립화학회지 Vol.28 No.1
In this study, spray characteristics of n-heptane and propane were investigated under different injection pressure using various imaging techniques such as Mie-scattering, DBI (diffuse back-illumination), and Schlieren imaging techniques. NI compact RIO system was used to control a test injector. Spray penetration length, length-to-width ratio and number of black pixels were calculated by using MATLAB software to compare spray characteristics of each fuel. Longer spray penetration length and higher length-to-width ratio were observed in propane spray because of flash boiling caused by high saturated vapor pressure. Spray collapse occurred in propane spray due to the high plume-to-plume interaction. Moreover, rapid evaporation occurred in propane spray, so that nozzle tip wetting could not be observed. Rapid evaporation of propane also caused fewer residual droplets compared to n-heptane spray. Therefore, propane is advantageous in reducing the generation of soot emission from large droplets that are not atomized. However, additional evaluation should be conducted considering combustion efficiency and the possibility of deposits by nozzle tip icing during fuel injection.
강보선 ( B. S. Kang ),이신표 ( S. P. Lee ) 한국분무공학회 2014 한국액체미립화학회지 Vol.19 No.2
Nanofluids is that metallic or nonmetallic nanometer-sized particles are dispersed in liquid and they can be used in various fields to increase the heat transfer rate. This study conducted experiments to evaluate whether the cooling efficiency of nanofluids is better than that of water in spray cooling. A heated surface was designed and fabricated to make the temperature distribution be linear, which was confirmed by three thermocouple measurements under the heated surface. Spray cooling experiments were conducted using water, 0.2% wt. (weight), and 0.5% wt. Al2O3 nanofluids at the pressure of 0.2 MPa and 0.3 MPa. Based on the results, it is shown that the cooling efficiency of nanofluids is higher than that of water especially in the region of single phase heat transfer. As a result, we can expect that nanofluids can be used as efficient coolants in the cooling of electronic packages where the temperature of the heated surface is not high enough for boiling incipience.
박준규 ( Jun Kyu Park ),전문수 ( Mun Soo Chon ),박성욱 ( Sung Wook Park ) 한국분무공학회 2012 한국액체미립화학회지 Vol.17 No.4
This study focused on comparing macroscopic characteristics of DME and diesel fuel experimentally. DME fuel is one of the most promising alternative fuels because of its superiority in atomization characteristic and clearness in terms of exhaust gas compared with existing fossil fuels. In addition, DME fuel has high cetane number so it could be applied to compression ignition engine. However because DME fuel exists in gas phase at room temperature and atmospheric pressure, and it corrodes rubber parts of fuel line, DME fuel is hard to apply to commercial vehicles. To establish knowledge about DME fuel and furthermore, to develop commercial DME vehicles such as passenger cars, many research have been proceeded steadily. The present study, by comparing spray characteristics of DME fuel to those of diesel fuel, improved atomization characteristics in DME were revealed. Injection quantity measurement and spray visualization experiment were progressed and it was revealed that DME fuel shows small injection quantity than that of diesel fuel and axial development of spray in terms of spray tip penetration decreases when DME fuel was injected.
고압 분사 디젤 인젝터의 노즐 형상이 분사 특성 및 분무 거동에 미치는 영향
이창식 ( C. S. Lee ),박성욱 ( S. W. Park ),전문수 ( M. S. Chon ) 한국분무공학회 2004 한국액체미립화학회지 Vol.9 No.1
N/A This paper describes the characteristics of injection rate and macroscopic behavior of fuel spray injected from common-rail type diesel injectors with different nozzle geometries. The injection rates according to the nozzle geometries were measured at different energizing duration of the injector solenoid and injection pressure by using the Bosch`s injection rate meter based on the pressure variation in the tube. The spray behaviors injected from the different nozzles were visualized using the spray visualization system composed of an Ar-ion laser, an ICCD camera, and a synchronization system at various injection and ambient pressures. It is revealed that VCO nozzle has higher spray tip velocity at the early stage of injection duration and wider spray cone angle than the mini-sac nozzles. Also the spray cone angle is increased with the increase of nozzle diameter.