• 한국분무공학회지
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• 제9권2호
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• pp.18-23
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• 2004

An experimental studies of conventional gasoline fuel pump were carried out to obtain fundamental data fur liquid phase LPG injection(LPLi) system. A regenerative type and a roller-vane type of pumps were investigated in various operational condition. The experiments were performed to obtain flow rate of LPG fuel as a function of pressure differences and temperatures. The regenerative pump had too low flow rate at some experimental conditions to use this pump system for LPLi fuel supply system. On the other hand, the roller-vane type pump can be applied to the system only if its check valve is modified. Cavitation might occur in this system which can result in system noise, flow rate variation, and pump durability problem. To solve these problems the system is needed to increase $NPSH_{re}$(required net positive suction head).

• 한국분무공학회지
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• 제4권1호
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• pp.45-54
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• 1999

The spray characteristics of a direct injection multi-hole diesel nozzle having the 2-spring nozzle holder were investigated by using the image processing system and a PDPA(phase Bowler particle analyzer) system. The spray tip penetration, the spray angle, and the droplet diameter and velocity with the variation of the pump speed, injection quantity were measured. From, the experiments, we know that there are small droplets which are not to be detected with spray image around the leading edge of the spray. In order to represent the mean characteristics of the intermittent spray very well, it is very important to set the time windows accurately. From the measurements along the axis of the spray, close to the nozzle, the initially injected droplets are overtaken by droplets that follow them. And also there are the maximum axial mean velocity and SMD at the following part of the leading edge of the spray.

• 한국분무공학회지
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• 제9권4호
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• pp.77-82
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• 2004

This paper describes the improvement of engine cooling system. To improve engine cooling performance, the authors approached in two ways. One is to increase water pump performance, changing of impeller shape and lightening of material were carried out. The second one is cooling efficiency rise, which were investigated with head gasket coolant flow passage optimization with flow visualization technique. The test results show that water pump performance was increased effectively, reduction of pump drive torque, and increase of pump flow-rate and pressure rise. Gasket hole pattern optimization test results represent an optimized head coolant flow which stands cross flow from exhaust to intake port side and small vortex were removed.

• Corrosion Science and Technology
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• 제14권2호
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• pp.59-63
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• 2015

Airless spray which is widely used for painting to ship blocks and hull sides is the coating method for attaching atomized paint material to the substrate using spray tip nozzle with compressed air. When the paint material which has high solid contents such as epoxy primer paint is atomized by passing through spray tip nozzle with high pressure, the nozzle composed of tungsten carbide(WC) undergoes the erosive wear, leading to widening of nozzle hole. The deformation of nozzle hole induces improper spray pattern and coating failures such as finger pattern and sagging because the conditions of spray pump pressure and paint flow rate for developing full spray pattern are changed. In this study, an appropriate replacement cycle of spray tip was predicted by measuring the erosive wear tendency as increasing the spraying time of epoxy primer paint.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.11-18
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• 2001

To clarify the influence of SAC shape of hole-type diesel nozzle on injection characteristics and spray patterns, the injection rate of three nozzle types(standard SAC nozzle, Needle-cut VCO nozzle and VCO nozzle) were measured by Zeuch's method and pictures of the sprays were taken by CCD camera. As the pump speed became higher, the injection characteristics of the three nozzles were different. Injection rate and perssure curves at the high pressure pipe in Needle-cut VCO nozzle were much more similar to the VCO nozzle than those of the SAC nozzle. When the needle was at pre-lift period for all speeds, the spray of the Needle-cut VCO nozzle showed almost the same shape as the SAC type nozzle. There was no differense in spray pattern at the needle full-lift periods.

• 한국분무공학회지
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• 제27권1호
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• pp.42-49
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• 2022

Flash boiling occurs in a couple of modern engineering systems and understanding its mechanism is important. In this experimental study, discharge coefficient of flash boiling spray from simple orifice nozzle was measured, and backlight imaging was acquired at injection pressure to 6.0 bar and temperature to 163℃ for the purpose. Pressurized water by pump was used for working fluid and was heated by electric heater and ejected through simple orifice nozzle diameter of 0.5 mm. High speed camera with long distance microscope was used for backlight imaging in two FoV having magnification of 3.3 and 0.64. The decrease of discharge coefficient according to degree of superheating and evolution of flash boiling spray imaged at various pressure and temperature were explained by the pressure field inside the injector.

• 한국분무공학회지
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• 제20권3호
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• pp.195-201
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• 2015

This study discusses a fuel injector test bench containing a mechanical type fuel supply system for heavy duty diesel engine. The main focus of this study was to evaluate the design stability of the test bench, which basically measures the injector durability of a multi-hole heavy duty injector by using pure diesel as a test fuel. In this experiment, diesel spray was controlled by a specially designed control box and all the experiments were carried out to measure e.g. fuel injection pressure and fuel injection quantity to understand the injection status which is interlinked with the stability factor of total test bench design. Also, the durability test was performed to understand the heavy duty operation lastingness of the designed system and the flow rate of the installed distributor pump in the fuel supply system of this studying test bench was compared with LO-1 and LO-2 pump. The results of the above mention tests revealed that the injector test bench design and control system can serve the purpose for heavy duty injector.

• 전기학회논문지
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• 제64권7호
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• pp.999-1004
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• 2015

In this paper, the study presents the development of 34kW class cryogenic induction motor using LNG Pump. Operating temperature of an induction motor using LNG Main Cargo Pump is at −163℃. Due to variation of the resistivity, these motor have different torque characteristics. So, it should design to considering the resistivity change. The most important consideration of induction machine operating is cryogenic temperature. If the temperature rise, LNG is vaporized. it is a major cause of pump failure. There are several causes of heat source like coreloss, hysterisysloss, copperloss. This paper analyzed the thermal distribution of the induction motor at rated speed operation.

• Journal of Dental Anesthesia and Pain Medicine
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• 제18권6호
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• pp.361-365
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• 2018

Background: Recently, we examined the effects of 2% lidocaine gel on the tactile sensory and pain thresholds of the face, tongue and hands of symptom-free individuals using quantitative sensory testing (QST); its effect was less on the skin of the face and hands than on the tongue. Consequently, instead of 2% lidocaine gel, we examined the effect of 8% lidocaine spray on the tactile sensory and pain thresholds of the skin of the face and hands of healthy volunteers. Methods: Using Semmes-Weinstein monofilaments, QST of the skin of the cheek and palm (thenar skin) was performed in 20 healthy volunteers. In each participant, two topical sprays were applied. On one side, 0.2 mL of 8% lidocaine pump spray was applied, and on the other side, 0.2 mL of saline pump spray was applied as control. In each participant, QST was performed before and 15 min after each application. Pain intensity was measured using a numeric rating scale (NRS). Results: Both the tactile detection threshold and filament-prick pain detection threshold of the cheek and thenar skin increased significantly after lidocaine application. A significant difference between the effect of lidocaine and saline applications was found on the filament-prick pain detection threshold only. NRS of the cheek skin and thenar skin decreased after application of lidocaine, and not after application of saline. Conclusion: The significant effect of applying an 8% lidocaine spray on the sensory and pain thresholds of the skin of the face and hands can be objectively scored using QST.

• 한국환경보건학회지
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• 제49권6호
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• pp.305-311
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• 2023

Background: The National Institute of Environmental Research (NIER)'s classification of and airborne fraction ratio for consumer chemical products (CCP) does not reflect the characteristics of various product classifications. Objectives: The purpose of this study was to reclassify the types of spray products according to the diverse spray characteristics of CCPs to evaluate the airborne fraction ratio of representative spray types and to compare them with previous CCPs types and airborne fraction ratios. Methods: One thousand seven hundred two products were selected through market research, and 932 newly reported products were selected. After that, 200 were selected to evaluate products with potential inhalation exposure. After classifying six product types that are expected to show differences in the airborne fraction ratio according to the type of product, a final 38 products were selected for use in the airborne fraction ratio through random sampling. Results: CCP has been reclassified from two to six types so that the characteristics of all products are well-reflected. The NIER simply had two airborne fraction ratios, but the results of experiments with six types of products showed a significant difference in values (p<0.01). Airborne fraction ratios of propellant general foam, pump general aerosol, and pump trigger foam in spray type, which were not previously present in NIER, were 7.1%, 24.4%, and 3.5%, respectively. Conclusions: For the diversified types of CCPs, the newly proposed classification was more appropriate than the existing NIER classification. The airborne fraction ratio was also different for each type, so a new value was suggested.