• Journal of ILASS-Korea
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• v.9 no.4
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• pp.17-23
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• 2004

Spray characteristics of a twin-hole air shrouded nonle designed for gasoline injectors was investigated by using laser diffraction particle analyzer (LDPA) and tomography reconstruction- A confined spray chamber which is optically accessible through a pair of glass windows was made to simulate the fuel injection condition in intake manifold of gasoline engine. The measurement was applied to the twin hole injector with and without an air shroud. It demonstrates that for the case with an air shroud, fine atomization is achieved and there exists a large number of fine droplets between the region of the main spray streams, which conforms with the spray visualization. The drop size distribution was investigated as a function of elapse time after fuel injection. The distribution was greatly affected by the measurement position from the injector exit. Also, the spatially resolved spray volume fraction and Sauter Mean Diameter (SMD) from line-of-sight data of the LDPA are tomographically reconstructed by Convolution Fourier transformation under the steady injection condition.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.107-112
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• 2001

The effect of ambient gas (steam) condensation on swirl spray characteristics were studied experimentally for low subcooling condition of the liquid. The configuration of the liquid(water) sheet and the breakup modes were examined. Also variation of the discharge coefficient, breakup length, local and the cross-sectional area-averaged SMD of droplets with the liquid flow(injection) rate were obtained. The perforation breakup mode appears dominant with condensation while the aerodynamic wave breakup mode is dominant without condensation(in the air environment). The discharge coefficient, breakup length and the mean drop sizes decrease in a same manner with increasing of the liquid flow rate for both cases(with and without condensation). The condensation effects are insignificant with the discharge coefficient. However, the local and cross-sectional area-averaged SMD are larger and the breakup length becomes shorter in the steam environment. The spray angle predicted from the volumetric flux distribution along the radial direction of the sprays in the steam environment becomes larger with condensation.

• Journal of Korean Library and Information Science Society
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• v.42 no.2
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• pp.237-255
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• 2011

This study is to find new methods in describing material type as content type and carrier type for the improvement of OPAC retrieval and the embodiment of work and expression of FRBR. It is hard to describe type vocabulary in cataloging because division of content and carrier taxonomy in KCR4 and KORMARC is not distinct. This study is to review the characteristics of material type list in RDA and ISBD(2010), and to examine the various type vocabulary and description methods of videorecording, soundrecording, and cartographic by retrieving KERIS DB. As a result, there is no consistency in applying type vocabulary between KCR4 and KORMARC. Also, libraries use the mix of content and carrier or detailed carrier vocabulary for local use. Therefore, it is need to define the function of GMD as content type, to expand and correct content and carrier vocabulary, and to express both content and carrier type in citation and detailed display. This study will contribute to embody the expression of FRBR.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1945-1950
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• 2000

When one build a building that posses Precison production process to be sensitive to vibration and SMD to procuce a large dynamic force, how do one predict & answer vibration control problem at building structure design at first stage, That is a question. It has tried to predict dynamic response and establish answering about global or local dynamic problem in building using experimental and analysis method. One of such a try, it be proposed Semi-Empirial Method that reduce error element of input information about dynamic analysis using dynamic experimental study and measurement data in the basis of real-structure. In this paper, the dynamic response problem about RC-structure building that will be set-up SMD produce large transient dynamic force using Semi-Empirical Method.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.62 no.2
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• pp.75-81
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• 2019

The objective of this study was to perform a systematic review of the literature for application of intranasal sodium citrate in the patients with olfactory dysfunction to help determine the sodium citrate treatments for this condition. Two authors independently searched the data base (Medline, Scopus, and the Cochrane database) for relevant studies from inception to January 2018. Included studies were randomized controlled studies published in English comparing topical sodium citrate application (treatment group) with saline (control group) in patients who had olfactory dysfunction. Outcomes of interest included the change of olfactory identification and threshold during 2 hours post-treatment. Three studies were enrolled in the meta-analysis. Compared with control group, treatment group did not increase posttreatment score of olfactory identification [standardized mean difference (SMD)=-0.03; 95% confidence interval (CI)=-0.29-0.24; I²=0%] and olfactory threshold (SMD=0.18; 95% CI=-0.09-0.45; I²=0%) significantly. In the degree of pre-post improvement of two outcomes, although treatment group statistically showed the significant improvement in olfactory threshold (SMD=0.30; 95% CI=0.05-0.55; I²=17%), the clinical significance of this outcome was meaningless. Similarly, there was no significant difference in olfactory identification between two groups (SMD=0.17; 95% CI=-0.11-0.45; I²=22%). Unlike the recent favorable results, our summated results presented the uselessness for the local application of sodium citrate in improving patient's olfactory function. However, we also had some limitation such as small sample size and inconsistent application methods. Therefore, larger trials and standardized methodology are needed to reach more stronger and exact results.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.177-186
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• 1996

A convolution alogorithm combined with Fourier transformation is applied to the tomographic reconstruction of the asymmetric spray structure to identify the local drop size and volume concentration. The line of sight intergrated data from Malvern particle analyzer with multiangular scanning form a basic information for the deconvolution. Linear interpolation is tested to obtain the effect of increasing number of scanning angles. This transformation method predicts well the structure of asymmetric spray. The tehnique can be extended to other line of sight combustion diagnostics.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.82-89
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• 2009

In order to investigate the spray characteristics according to diesel and bioethanol blending with biodiesel fuel, macroscopic spray characteristics were analyzed from the comparison of the effect of the injection pressure, ambient pressure and density on the spray tip penetration and spray cone angle. In addition, spray atomization characteristics were studied with local and overall Sauter mean diameter (SMD) and the contour map of SMD distribution at various injection conditions. It was revealed that the spray tip penetration of biodiesel fuels blended with diesel and ethanol was shorter than that of an undiluted biodiesel fuel at low injection pressure. However, the difference of spray tip penetration among three test fuels reduces at a high injection pressure. Increase of the ambient gas density leads to the decrease of the spray tip penetration of three test fuels. When diesel and ethanol fuels add to an undiluted biodiesel fuel, spray cone angle increases due to the decrease of the fuel density at the same ambient pressure condition. On the other hand, the droplet mean diameter decreases due to the reduction of the kinematic viscosity and surface tension.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.381-386
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• 2007

Jet-A spray, evaporation and combustion were numerically analyzed in annular type model combustor using KIVA-3V. Liquid fuel's atomizing was affected by flow field near droplet. When cooling flow was not optimized, SMD was increased, and equivalence ratio was horizontally distributed in combustor's downstream. Flame spread out horizontally and separated in combustors downstream. Flame center was separated by cooling flow. Flame separation made local high temperature in downstream that caused NO increase.

• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4307-4326
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• 2024

This study investigates Equivalent Spherical Diameter (ESD) estimation at high inlet velocity pool scrubbing conditions using the Interfacial Area Transport Equation (IATE) diameter model including bubble-induced turbulence and interphase modeling. The compatibility of area-averaged Sauter Mean Diameter (SMD), areaaveraged Local Equivalent Diameter (LED) and void-weighted area-averaged LED approaches to estimate the ESD are explored and the proposed model is validated against available experimental data. The study reveals that the prevalent constant ESD assumption in pool scrubbing codes is not universal by showcasing a decreasing trend along the column due to intensive bubble breakup. The area-averaged LED approach fails to capture this trend, while the area-averaged SMD and void-weighted area-averaged LED approaches provide accurate estimations aligned with experimental data. Turbulence parameters, interfacial forces, and diameter modeling are identified as crucial for accurate predictions of flow and geometrical variables by setting up the OpenFOAM framework. A sensitivity analysis indicates that the inlet velocity has an acceptable effect on the ESD along the column. The ESD increases near the exit and decreases in the swarm region by increasing the inlet velocities. Turbulent intensity reduces ESD across all column sections while changes in aspect ratio minimally impact ESD. The study shows promise in developing correlations that take into account the spatial variation of ESD in pool scrubbing conditions.

• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.449-456
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• 2003

In this study, numerical and experimental analysis on the spray atomization characteristics of a GDI injector is performed. For numerical approach, four hybrid models that are composed of primary and secondary breakup model are considered. Concerning the primary breakup, a conical sheet disintegration model and LISA model are used. The secondary breakup models are made based on the DDB model and RT model. The global spray behavior is also visualized by the shadowgraph technique and local Sauter mean diameter and axial mean velocity are measured by using phase Doppler particle analyzer Based on the comparison of numerical and experimental results, it is shown that good agreement is obtained in terms of spray developing process and spray tip penetration at the all hybrid models. However, the hybrid breakup models show different prediction of accuracy in the cases of local SMD and the spatial distribution of breakup.