• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.803-806
• /
• 2002

Flame spray pyrolysis was applied to improve the photoluminescence characteristics of blue-emitting $Sr_5(PO_4)_3Cl:Eu^{2+}$ phosphor particles with high brightness for the application to LED phosphor. $Sr_5(PO_4)_3Cl:Eu^{2+}$ prepared from conventional spray pyrolysis had poor PL intensity than that of commercial products under long-wavelength ultraviolet(UV). $Sr_5(PO_4)_3Cl:Eu^{2+}$ phosphor particles prepared by flame spray pyrolysis had PL intensity as same as that of commercial products under long-wavelength UV. Hollow morphology and porous structure of the particles prepared by the flame spray pyrolysis disappeared after posttreatment. Even though the $Sr_5(PO_4)_3Cl:Eu^{2+}$ phosphor particles prepared by the flame spray pyrolysis had irregular shape, the particles had dense structure and clear surface property.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.2
• /
• pp.548-558
• /
• 1995

An experimental investigation has been conducted to study the spray and combustion characteristics using the air-assisted twin fluid atomizer. Axial mean and fluctuating velocity components as well as drop-size distributions in non-reaction spray were measured with a nonintrusive phase doppler technique. Droplet number density distributions were also visualized using high speed CCD camera. Locations of spray and flame boundaries are obtained by direct photographic method. It is confirmed that at the fixed fuel flow rate, the increase of the atomizing air flow causes improvements on both spray and combustion characteristics under stable flame conditions. Internal group combustion modes where flame is located inside the spray boundary are observed to exist in the upstream region of higher droplet number density.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.24 no.1
• /
• pp.36-43
• /
• 1988

Boilers and diesel engines have many problems because their exhaust particles, i.e., soot have lots of bad influence on environment. And it's spray and flame have fundamentally axial symmetric shape. To investigate the relationship between fuel concentration distribution of spray and soot concentration distribution as well as temperature distribution of flame, we made a axial symmetric two phase spray-flame and analyzed the structure of is. The measuring method is the principle of the light extinction method for the spray-flame and onion peeling model is applied to analyze the radial distribution of fuel and soot concentration. The temperature of flame is measured by ø 0.4mm Pt-Pt.RH 3% thermocouple. The oils for the experiments are diesel oil and 10% water emulsified diesel oil. It was found that the soot concentration becomes higher as it comes near to the center of flame, and the fuel concentration does, too. And the soot concentration level of diesel oil is generally higher than that of the 10% water emulsified fuel. The maximum flame temperature of diesel oil is 1,17$0^{\circ}C$, however, 10% water emulsified diesel oil is 1,27$0^{\circ}C$.

• Journal of ILASS-Korea
• /
• v.16 no.1
• /
• pp.37-43
• /
• 2011

The present study conducted computational simulation for multiphase flow in the flame spray coating process with commercially available Ni-Cr powders. The flows in a flame spray gun is characterized by very complex phenomena including combustion, turbulent flows, and convective and radiative heat transfer. In this study, we used a commercial computational fluid dynamics (CFD) code of Fluent (ver. 6.3.26) to predict gas dynamics involving combustion, gas and particle temperature distributions, and multi-dimensional particle trajectories with the use of the discrete phase model (DPM). We also examined the effect of particle size on the flame spray process. It was found that particle velocity and gas temperature decreased rapidly in the radial direction, and they were substantially affected by the particle size.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.17 no.6
• /
• pp.38-45
• /
• 2018

Molybdenum flame spray coatings are widely used in industrial fields to enhance the performance of mechanical component parts such as pistons, shafts and clutches. This study investigates the surface characteristics of high tensile brass with molybdenum flame spray treatment using the clutch material for small ship. The surface characteristics after molybdenum flame spray treatment in high tensile brass were quantitatively analyzed for surface composition, coating layer thickness, friction coefficient, abrasion width and phenomenon, micro-hardness, and surface roughness.

• Journal of Mechanical Science and Technology
• /
• v.17 no.12
• /
• pp.2019-2026
• /
• 2003

Spray and combustion characteristics of a dump-type ram-combustor equipped with a V-gutter flame holder were experimentally investigated. Spray penetrations with a change in airstream velocity, air stream temperature, and dynamic pressure ratio were measured to clarify the spray characteristics of a liquid jet injected into the subsonic vitiated airstream, which maintains a highly uniform velocity and temperature. An empirical equation was modified from Inamura's equation to compensate for experimental conditions. In the case of insufficient penetration, the flame in the ram-combustor was unstable, and vice versus in the case of sufficient penetration. When the flame holder was not equipped, the temperature at the center of the ram-combustor had a tendency to decrease due to the low penetration and insufficient mixing. Therefore, the temperature distribution was slanted to the low wall of the ram-combustor. These trends gradually disappeared as the length of the combustor became longer and the flame holder was equipped. Combustion efficiency increased when the length of the combustor was long and the flame holder was equipped. Especially, the effect of the flame holder was more dominant than that of the combustor length in light of combustion efficiency.

• Korean Journal of Materials Research
• /
• v.14 no.8
• /
• pp.600-606
• /
• 2004

$Zn_{2}SiO_{4}:Mn$ phosphor particles were prepared by a flame spray pyrolysis method. It has been generally known that the high-temperature flame enables fast drying and decomposition of droplets. In the present investigation, the morphology and luminescent property of $Zn_{2}SiO_{4}:Mn$ phosphor were controlled in a severe flame preparation condition. The particle formation in the flame spray pyrolysis process was achieved by the droplet-to-particle conversion without any evaporation of precursors, which made it possible to obtain spherical $Zn_{2}SiO_{4}:Mn$ particles of a pure phase from a droplet. Using colloidal solutions wherein dispersed nano-sized silica particles were adopted as a silicon precursor. $Zn_{2}SiO_{4}:Mn$ particles with spherical shape and filled morphology were prepared and the spherical morphology was maintained even after the high-temperature heat treatment, which is necessary to increase the photoluminescence intensity. The $Zn_{2}SiO_{4}:Mn$ particles with spherical shape, which were prepared by the flame spray pyrolysis and posttreated at $1150^{\circ}C$, showed good luminescent characteristics under vacuum ultraviolet (VUV) excitation.

• Journal of the Korean Society of Combustion
• /
• v.17 no.3
• /
• pp.46-52
• /
• 2012

3D DNS is performed for n-heptane spray turbulent jet combustion. Diesel-like conditions are considered including single and multiple injections. Conditional statistics are obtained for multiple Lagrangian flame groups of sequentially evaporating fuel. Each fuel group represents the conditional statistics of an independent Lagrangian flame group. Sequentially evaporating fuel goes through different histories and residence times over the ignition delay period. Multiple flame groups are required for accurate description of combustion of a spray jet that goes through a long injection duration or multiple injections.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.19 no.1
• /
• pp.40-45
• /
• 1983

The paper describes an experimental investigation of axisymmetric diesel spray and flame which is held in rapid compression machine (RCM) with electromagnetic single injection nozzle. The axisymmetric diesel spray and flame are taken with high speed photograph and analysis it with image processor. The data presented include fuel concentration of spray, flame temperature, soot concentration of flame in axial and radial direction at a moment and compared it with each other.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.937-942
• /
• 2000

The characteristics of spray combustion and dropsize of spray through twin-fluid atomizer was experimentally investigated. The distribution of flame temperature have an effect on the generation of NOx. To investigate there effects, flame temperature with different spray shape was observed. The spray shape was varied by various bluff-bodys. Mean temperature were measured by thermocouple respectively, and NOx concentration was measure by NOx analyser. Distribution of droplet sizes were measured by PMAS. The result showed that the flame with wide distribution has lower temperature and lower NOx emission compared with narrow.