• Transactions of the Korean Society of Automotive Engineers
• /
• v.3 no.1
• /
• pp.118-130
• /
• 1995

Fuel spray in a gasoline engine is a significant factor for the decision of engine power, pollutant emission and the design of intake manifold system. Three kinds of fuel which has other physical properties are chosen in this study, and it is observed using an image processing method that the mechanism and structure of free fuel spray with a throttle type gasoline injector, and the detailed characteristics of droplet size and velocity distributions are obtained by macro and micro-scopic measuring method respectively. It is verified that the initial breakup behaviors are depended on We like the result of Reitz's study, and also observed that the spray of octane and solvent with Re of 210~330 and 270~330 respectively are better than ethanol which has relatively high density and viscosity.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.12
• /
• pp.992-999
• /
• 2009

The focus of this study is placed on the behavior characteristics of gasoline spray under condition field of room temperature and pressure. To analyze the behavior and flow characteristics of injected fuel spray is important in speculation of mixture formation process. Also the exhausted emissions from actual engines can be controlled by the analyzed results. The ${\varphi}$(degree of freedom) and K(energy ratio of particle motion) are selected as the simulation parameter. The factors affect characteristics of spray structure, and the factors are included in the sub-program of the KIVA-II code. In this study, the simulation study by modified KIVA-II code was conducted and the calculated results obtained by the modified KIVA-II code show good agreements with experimental results. As a result, applying the improved TAB model with ${\varphi}$=8 and K=2 to simulation analysis of the KIVA-II code is sufficiently useful for analyzing the macro characteristics in spray structure, such as the spray tip penetration of injected fuel spray.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.1
• /
• pp.279-288
• /
• 2003

This study is the development of method on repairing concrete structure for progressing the durability of reinforced concrete. This method is wet spray method which compress and conduct mortar pre-mixed with polymer powder to hose by high pressure pump and spray it on the section of concrete structure through nozzle made specially. Characters of this method are that materials are selected with the sort of structure and the cause of deterioration and macro pores are removed in repaired section by conducting with high pressure and spraying with high velocity for progressing the durability of concrete structure. This study has carried out that the minimum capacity of rebound was measured with various condition and physical properties of sample made by spray method were estimated in comparing with sample made by previous hand method. Also, properties of long-term have carried out after this method was applied on site. According to experimental study, the capacity of rebound showed below 5% and physical properties of sample made by spray method were superior to that of sample made by hand method and physical and durable properties of long-term showed excellence.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.1
• /
• pp.54-61
• /
• 2005

Characteristics of sprays injected by gas/liquid coaxial atomizers operated at atmospheric pressure are studied using shadowgraph, mechanical patternator and PDPA. The gas-to- liquid momentum flux ratio(M) and the liquid Reynolds number(Re) are selected as key parameters in characteristics of gas/liquid coaxial sprays from the dimensional analysis. The properties of shear coaxial sprays are compared with those of swirl coaxial sprays through the macroscopic and microscopic analysis. Macroscopic similarities between shear and swirl coaxial sprays are revealed under flow conditions of high momentum flux ratio. Also, empirical correlations between the mean drop diameters(D32) and operating conditions of coaxial sprays are proposed in this paper.

• Particle and aerosol research
• /
• v.7 no.3
• /
• pp.79-85
• /
• 2011

Porous $TiO_2-SiO_2$ particles were synthesized by co-assembly of nanoparticles of $TiO_2$ and $SiO_2$ in evaporating aerosol droplets. Poly styrene latex (PSL) particles were employed as a template of porous particles. Flowrate of dispersion gas, weight ratio of $TiO_2/SiO_2$ and $SiO_2$ concentration in the precursor, and PSL size were chosen as process variables. The morphology, crystal structure, chemical bonding, and pore size distribution were analyzed by FE-SEM, XRD, FT-IR, BET. The morphology of porous $TiO_2-SiO_2$ particles was spherical and the average particle size range were from 1 to $10{\mu}m$. The particles were composed of meso and macro pores. The average particle diameter and pore volume of the as prepared particles were dependant on process variables. It was found that UV-Vis absorption of the porous particles was comparable with pure $TiO_2$ nanoparticles even though $TiO_2/SiO_2$ ratio is low in the porous particles.