A Comparison of Effects of Ambient Pressure on the Atomization Performance of Soybean Oil Methyl Ester and Dimethyl Ether Sprays

Oil & Gas Science and Technology, Nov 2010

The purpose of this study is the experimental investigation of Soybean oil Methyl Ester (SME) and DiMethyl Ether (DME) spray characteristics injected through the common-rail injection system under various ambient pressures. A high pressure chamber that can be pressurized up to 4 MPa was utilized for a change of ambient pressure. In order to compare the spray development and atomization characteristics, the images of SME and DME were obtained by using a high speed camera with two metal halide lamps under various ambient pressures in the spray chamber. From these spray images, the spray characteristics such as the spray penetration from the nozzle tip, maximum radial distance, and spray diameter were measured and analyzed. In addition, the Sauter Mean Diameter (SMD) of two fuels under ambient pressure was analyzed using the droplet measuring system. It was revealed that the axial distance of spray from the nozzle tip of the SME spray is longer than that of DME spray under same injection condition. The axial penetration, maximum radial distance, and spray diameter decreased when the ambient pressure in the chamber increased. As the ambient pressure increased, the SMD decreased and the DME spray showed a superior atomization performance compared to the SME spray.Le but de cette étude est l’investigation expérimentale de l’effet de diverses pressions ambiantes sur les caractéristiques des sprays (issus d’un système "common rail") de methylester d’huile de soja (SME) et de dimethyléther (DME). La pression ambiante dépend de la chambre et sa valeur la plus haute peut monter jusqu’à 4 MPa. Pour comparer le développement de spray et la caractéristique d’atomisation, des images de spray de SME et DME à différentes pression ambiantes sont obtenues avec une caméra à haute vitesse à deux lampes de métal halide. Les caractéristiques du spray, comme la pénétration, la distance radiale maximale et le diamètre de spray, sont mesurées et analysées. De plus, le diamètre de Sauter (SMD) des deux carburants à différentes pressions est mesuré. On a constaté que, dans les mêmes conditions, la distance de pénétration du spray de SME est supérieure à celle du spray de DME. La pénétration axiale, la distance radiale maximale et le diamètre du spray décroissent quand la pression ambiante croît. Quand la pression ambiante croît, le SMD décroît et le spray de DME montre plus d’atomisation que celui de SME.

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A Comparison of Effects of Ambient Pressure on the Atomization Performance of Soybean Oil Methyl Ester and Dimethyl Ether Sprays

Oil & Gas Science and Technology - Rev. IFP Energies nouvelles, Vol. A Comparison of Effects of Ambient Pressure on the Atomization Performance of Soybean Oil Methyl Ester and Dimethyl Ether Sprays H.J. Kim 2 S.H. Park 1 M.S. Chon 0 C.S. Lee 2 0 Department of Energy System Engineering, Chungju National University , Chungju - Korea 1 Graduate School of Hanyang University , 17 Haengdang-dong, Seoungdong-gu, Seoul 133-791 - Korea 2 Department of Mechanical Engineering, Hanyang University , 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 - Korea - A Comparison of Effects of Ambient Pressure on the Atomization Performance of Soybean Oil Methyl Ester and Dimethyl Ether Sprays - The purpose of this study is the experimental investigation of Soybean oil Methyl Ester (SME) and DiMethyl Ether (DME) spray characteristics injected through the common-rail injection system under various ambient pressures. A high pressure chamber that can be pressurized up to 4 MPa was utilized for a change of ambient pressure. In order to compare the spray development and atomization characteristics, the images of SME and DME were obtained by using a high speed camera with two metal halide lamps under various ambient pressures in the spray chamber. From these spray images, the spray characteristics such as the spray penetration from the nozzle tip, maximum radial distance, and spray diameter were measured and analyzed. In addition, the Sauter Mean Diameter (SMD) of two fuels under ambient pressure was analyzed using the droplet measuring system. It was revealed that the axial distance of spray from the nozzle tip of the SME spray is longer than that of DME spray under same injection condition. The axial penetration, maximum radial distance, and spray diameter decreased when the ambient pressure in the chamber increased. As the ambient pressure increased, the SMD decreased and the DME spray showed a superior atomization performance compared to the SME spray. - 884 INTRODUCTION The fuel spray characteristics assumed different aspects according to the various injection and ambient conditions such as injection pressure, energizing duration, injection mass, spray cone angle, ambient pressure, and ambient temperature in the combustion chamber. Particularly, in a High Speed Direct Injection (HSDI) diesel engine, spray characteristics are greatly influenced by the ambient conditions in the cylinder. In addition, the atomization and spray characteristics of fuel were directly influenced on the combustion performance and emission characteristics. Many studies on the diesel spray, SME and DME spray characteristics under various ambient conditions of high pressure and temperature have been conducted by researchers. Paryi et al. (1996) conducted the investigation on the evolution of diesel spray under a high gas density by using high speed photography and phase Doppler anemometry. They reported that a spray cone angle was more influenced by a gas density than the injection condition. The experimental and numerical studies on the diesel spray penetration at a high pressure and temperature under various injection pressures were carried out by Abdelghaffar et al. (2007) . They suggested that the diesel spray penetration length decreased with the increasing of an in-cylinder pressure, and tip penetration decreased due to the increase of vaporization rate at the high ambient gas temperature. Roisman et al. (2007) studied the experimental and theoretical investigations on the diesel spray penetration and cone angle at the ambient pressure in the chamber. Their work suggested that the spray penetration was determined by two major factors such as inertia of liquid/air mixture in the steady conical spray region and the particular conditions near the leading spray edge. The research on the vapor/liquid phase penetration and spray cone angle under ambient condition equivalent to an actual engine cylinder was conducted by Yamashita et al. (2007). They found that the vapor phase penetration increased but the penetration of rich mixture becomes shorter when the injection pressure increased. Besides being the diesel spray characteristics as the ambient condition, investigations on alternative fuels for the diesel fuel have been actively advanced to solve the environmental pollution. Among many alternative fuels, Soybean oil Methyl Ester (SME) and DiMethyl Ether (DME), including a large amount of the oxygen molecular, can be produced with lower exhaust emissions, such as soot and particulate matter, compared to diesel fuel. These fuels are suitable for the compression ignition engine due to a high cetane number. Therefore, the SME and DME fuel are in the spotlight of representative alternative fuel instead of the diesel fuel. However, the SME fuel has demerits such as the disturbance factor of atomization by a high viscosity, a problem in a coldstart due to crystallizing property, and the acidification during long-term storage. In the case of DME fuel, (...truncated)


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H.J. Kim, S.H. Park, M.S. Chon, C.S. Lee. A Comparison of Effects of Ambient Pressure on the Atomization Performance of Soybean Oil Methyl Ester and Dimethyl Ether Sprays, Oil & Gas Science and Technology, 2010, pp. 883-892, Volume 65, Issue 6, DOI: 10.2516/ogst/2009069