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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of ILASS-Korea
Journal Basic Information
Journal DOI :
Institute for Liquid Atomization and Spray Systems-Korea
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Dec 2008
Volume 13, Issue 3 - Sep 2008
Volume 13, Issue 2 - Jun 2008
Volume 13, Issue 1 - Mar 2008
Selecting the target year
Mixing and Combustion Characteristics of a CNG and Air according to Fuel Supply Conditions in a DI Engine
Kang, Jeong-Ho ; Park, Jong-Sang ; Yeom, Jeong-Kuk ; Chung, Sung-Sik ; Ha, Jong-Yul ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 1~8
It was investigated how fuel injection timing - early injection and later injection - in conjunction with throttle open rate effect the fuel-air mixing characteristics, Engine power, combustion stability and emission characteristics on a DI CNG spark Engine and control system that had been modified and designed according to the author's original idea. It was verified that the combustion characteristics were changed according to fuel injection timings and Engine conditions determined by different throttle open rates and rpm. It was found that the combustion characteristics greatly improved at the complete open throttle rate with an early injection timing and at the part throttle rate with a late injection timing. Combustion duration was governed by flame propagation duration in a late injection timing and by an early flame development duration in an early injection timing. As the result, we discovered that combustion duration is shortened, lean limit is improved, air-fuel mixing conditions controlled, and emissions reduced through control of fuel injection timing according to change of the throttle open rate.
Heat Transfer Characteristics by the Right Angled Triangle Rod Array in Impinging Air Jet System
Kum, Sung-Min ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 9~15
This experimental study was carried out to examine the heat transfer characteristics of impinging air jet on a flat plate with a set of right angled triangle rods. Each right angled triangle rod in the array was positioned normal to the flow direction and parallel to the flat plate surface. The clearances from a right angled triangle rod to flat plate surface (C=1, 2 and 4 mm) and the distance from nozzle exit to flat plate (H=100 and 500 mm) were changed for the pitch between each right angled triangle rods (P=40 mm). As a result, heat transfer shows best performance at the clearance of C=1 mm, in case clearance changed, and the average heat transfer enhancement rate increased up to 47% compared to the result of a flat plate without a right angled triangle rod.
Examination of 2-Fluid Nozzle and 3-Fluid Nozzle for Fuel Reformer of 5 kW SOFC System
Kwon, Hwa-Kil ; Lee, Chi-Young ; Lee, Sang-Yong ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 16~21
In the present study, the 2-fluid nozzle and 3-fluid nozzle to atomize the diesel and water with air for the fuel reformer of SOFC system were experimentally examined. In the 2-fluid nozzle, the diesel and water were alternately atomized due to bislug flow pattern, and it implies that the mixing of both liquids strongly affects the atomization pattern. On the other hand, in the 3-fluid nozzle, the diesel and water were atomized simultaneously due to the separated injection channels without mixing problem. Therefore, compared to the 2-fluid nozzle, the 3-fluid nozzle is suitable for the stable operation of the fuel reformer. In case of the 3-fluid nozzle, Type A where the air was supplied through the central channel was the most efficient.
Analysis of the False Diffusion Effects in Numerical Simulation of Diesel Spray Impinging on Inclined Walls
Gwon, H.R. ; Lee, S.H. ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 22~27
The false diffusion occurs generally when the flow is oblique to the grid lines and when there is a non-zero gradient of the dependent variable in the direction normal to the flow. This numerical problem can overestimate diffusion terms in the continuous phase, causing the numerical inaccuracy for the simulation of impinging sprays on inclined walls because most of spray calculation uses rectangular grid system. Therefore, the main objective of this article is to investigate numerically the influence of false diffusion on numerical simulation for spray-wall impingement on inclined walls. It is found that unlike the spray impingement normal to the wall, the numerical diffusion exists in the case when diesel sprays impinge on the inclined walls with different angles. The results show that the correction function should be considered for accurate prediction of spray penetration length and more elaborate numerical schemes should be utilized to reduce the false diffusion.
Numerical Studies on the Combustion Characteristics and Pollutant Formation for the DME Fueled Diesel Engine
Yu, Yong-Wook ; Lee, Jeong-Won ; Kim, Yong-Mo ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 28~33
The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure diesel engines. In order to realistically simulate the dimethyl ether (DME) fueled diesel engine, the high pressure vaporization model is utilized and the interaction between turbulence and chemistry is treated by employing the Representative Interactive Flamelet (RIF) model. The detailed chemisty consisted of 336 elementary reaction steps and 78 species is used for DME/air reaction. Numerical results indicate that the RIF model with high pressure vaporization model successfully predicts the essential feature of the combustion processes and pollutants formations in the DME fueled diesel engines.
Molecular Dynamics Study on Behaviors of Liquid Cluster with Shape and Temperature of Nano-Structure Substrate
Ko, Sun-Mi ; Jeong, Heung-Cheol ; Shibahara, Masahiko ; Choi, Gyung-Min ; Kim, Duck-Jool ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 34~41
Molecular dynamic simulations have been carried out to study the effect of the nano-structure substrate and its temperature on cluster laminating. The interaction between substrate molecules and liquid molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand behaviors of the liquid cluster on nano-structure substrate. In the present model, the Lennard-Jones potential is applied to mono-atomic molecules of argon as liquid and platinum as nano-structure substrate to perform simulations of molecular dynamics. The effect of wettability on a substrate was investigated for the various beta of Lennard-Jones potential. The behavior of the liquid cluster and nano-structure substrate depends on interface wettability and function of molecules force, such as attraction and repulsion, in the collision progress. Furthermore, nano-structure substrate temperature and beta of Lennard-Jones potential have effect on the accumulation ratio. These results of simulation will be the foundation of coating application technology for micro fabrication manufacturing.
Atomization of Shear-Thinning Liquid Slurry Discharging from Fan Spray Nozzles
An, S.M. ; Ryu, S.U. ; Lee, S.Y. ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 42~50
In the present work, atomization characteristics of shear-thinning liquid slurry discharging from fan spray nozzles were studied experimentally for spray painting applications. The effects of solid particle size and concentration on the properties (especially on the viscosity) of suspensions and mean drop size were examined by using model fluids. In the range of low particle concentration (below 3 wt%), the fluid viscosity was primarily determined by the particle size. On the other hand, in the range of high particle concentration (higher than 10 wt%), the agglomeration phenomenon and the oil absorption capability of solid particles played major roles in determining the fluid viscosity. In the high concentration region, which most of the paints belong to, the fluid became more viscous and the shear thinning behavior appeared more prominent as the particle concentration was increased. In this region, mean drop size(SMD) decreased more rapidly with the increase of the injection pressure. Also, SMD became larger with the higher particle concentration and the larger particle size.
Effects of Fuel Injection Conditions on Spray Characteristics of Commercial Biodiesel Fuel
Hong, Yeon-Ki ; Chon, Mun-Soo ;
Journal of ILASS-Korea, volume 13, issue 1, 2008, Pages 51~57
The objective of this study was to investigate the spray characteristics of commercial biodiesel fuel at various fuel injection conditions. To examine the effect of various factors on the development of a biodiesel sprays, experiments were conducted at the various injection pressures, ambient pressures and blending ratio of bio-diesel fuels. As a result of experimental study, it was shown that the increase of blending ratio of biodiesel had little influence on spray behaviors under applied fuel injection condition in this study. Because macroscopic characteristics of biodiesel-blended diesel fuel were almost same as that of petrodiesel fuels, it was found that the commercial biodisel is applicable to conventional diesel engine.