• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.36-36
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• 1999

일반적으로 이젝터(ejector)는 노즐로부터 팽창하는 높은 운동량을 가지는 주 유동과 주변의 낮은 운동량을 가지는 유동사이에서 생기는 강한 전단력을 이용하여, 분류 주변의 유체를 보다 고압의 부분까지 압축하여 수송하는 장치이다. 이젝터는 노즐(nozzle)과 디퓨저(diffuser)로 되어 있으며, 회전부분이나 활동부분을 가지지 않는 유체기계이므로 고장이 적고, 소형임에도 불구하고 대용량의 유체를 압축할 수 있는 특징을 가지고 있다. 그러나 이젝터의 구동은 유체의 전단력만을 이용하므로 효율이 낮은 단점이 있으므로, 이젝터 형상의 최적설계 및 성능개선을 위한 연구가 필요하다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.51-57
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• 2021

The seawater cooling system of naval ships is installed to remove the toxic substances generated by CBR (Chemical, Biological, and Radiological) warfare and reduce the infrared signature of naval ships from outside the hull. The dispersion range of the nozzle is determined according to the injection pressure of seawater and the nozzle type. Therefore, it is necessary to select the appropriate injection pressure and design the optimal nozzles to increase the seawater dispersion area and maximize the efficiency of the cooling system. In this study, the applying feasibility of 3D printing technology to produce an injection nozzle for the seawater cooling system was examined. To this end, the extruded plastic specimens were fabricated by 3D printing, and the physical properties of the specimens were estimated through tensile testing. After this, the strain and stress of the nozzle as a function of the pressure were simulated by applying the estimated results to the finite element analysis. The finite element analysis results showed that the nozzle remained within the elastic range at the optimal pressure. The nozzle was estimated to be structurally stable, and the possibility of this study was confirmed.

• Journal of Animal Environmental Science
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• v.11 no.2
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• pp.111-116
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• 2005

The purpose of this study was to analyze the performance of vehicle disinfector nozzles using at the livestock farm. The nozzle of vehicle disinfectors was measured spraying rate and equality distribution ratio by pressures. The spraying rate of TK-I's nozzle was 1,605 ml/min at 3 MPa, TK-II's nozzle was 2,020 ml/min, JA's nozzle was 1,150 ml/min and IS's nozzle was 795 ml/min. The number of nozzles of TK-I's, TK-II's, JA's and IS's for reasonable spraying rate($25{\ell}/min$. at 3 MPa) was respectively 16, 13, 22 and 32 units. The equality distribution ratio of TK-I's nozzle by pressures was equalized and the nozzles of TK-II's, JA's and IS's was sprayed to the center or side more then other sides in the measured boxes.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.16-27
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• 2018

A basic numerical analysis was performed to confirm the possibility of combining a dual bell nozzle and an Expansion-Deflection(E-D) nozzle. The dual bell nozzle was designed based on the first-stage nozzle of the Korean Space Launch Vehicle that is being developed, and the E-D nozzle concept was applied to the dual bell nozzle. The inlet condition was analyzed by applying eight types of frozen flow analysis, and k-${\omega}$ SST was selected as the turbulence model. The number of optimal grids was obtained as 240,000 through the grid sensitivity analysis. As a result, it was confirmed that the transition altitude increased owing to over-expansion when the E-D nozzle concept was applied to the dual bell nozzle, and the specific impulse gain was obtained at high altitudes compared with the KSLV-II first-stage engine.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1240-1247
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• 2003

Water jet nozzle for LCD has been used as a wet cleaning process in many industries. It is necessary for the nozzle to consider cleaning effect and flux. In this paper, we applied the bubble dynamic theory(Rayleight-Plesset equation) to improve the cleaning efficiency. Generally, Rayleigh-Plesset equations for cavitation bubbles are used in analyzing computer simulation for caviting flows. Burst of bubbles causes potential energies and we can use these energies to remove organic and inorganic compounds on the LCD. Therefore, it is necessary to analyze the bubble generations and axiomatic design by computational fluid dynamics(CFD). By comparing the weight matrix of neural networks to the design matrix of axiomatic design, we propose methods to verify designs objectively. The optimal solution could be deduced by the regression analysis using the design parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1113-1114
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• 2010

• 한국가스학회:학술대회논문집
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• 2005.10a
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• pp.208-215
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• 2005

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.41-47
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• 2013

This study was carried out to improve the design of fuel injection nozzle for marine medium speed diesel engine. For this purpose, fuel injection nozzle was modeled and simulated using CATIA V5R19 and FLUENT & MSC Nastran. Analyses of flow and heat transfer, respectively, were performed to find the optimal design of fuel injection nozzle. As the results, big pressure drop, which may lead to cavitation damage, was occurred at inlet of fuel injection hole with diameter 0.3mm. Furthermore, it was confirmed that the increase of mean temperature of fuel injection nozzle was almost a half in comparison with that of fuel injection nozzle tip.

• Journal of computational fluids engineering
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• v.2 no.1
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• pp.66-72
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• 1997

Optimum nozzle design exploiting the method of characteristic(M.O.C) has been in application as an efficient design methodology targeting a less weighted and short expansion nozzle. This paper treats the optimum nozzle design and the analysis of the inviscid compressible flow inside. Based on traditional Rao's method, the optimum nozzle design is coded with minor modifications for the identification of the control surface across which the mass flux should be conserved. Internal flow field is simulated numerically by M.O.C and implicit/explicit Taylor-Galerkin finite element method(F.E.M) with the aid of adaptive remeshing to capture the shock wave, hence improve the accuracy. Designed and calculated flow fields due to the separate analyses show that the mass flux predicted by optimum nozzle design with M.O.C is not conserved across the control surface and the sonic line should be located upstream of the nozzle throat. Rao's optimum nozzle design methodology exaggerates the momentum thrust and tends to overemphasize the engine performance loss.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.129-130
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• 2008

텐터의 성능을 결정하는 요인은 여러 가지가 있으나, 섬유의 종류 또는 가공 공정의 목적에 따라 적절한 건조속도 및 효율성, 원단의 전 폭에 걸친 건조 균일도, 습윤 공기의 자동 배출, 원단의 장력 및 오버피드, 그리고 각종 자동화 제어 장치의 활용 등으로 구분되어 질 수 있으며, 그러므로 텐터기 챔버 내부의 공간구조에 따른 비효율적 유로형상과 공기 분사노즐 정확한 압력 및 온도분포에 대한 현장 기초자료를 확보하여 텐터의 에너지 절약 및 건조 원단의 품질을 향상시킬 수 있는 구조의 설계가 요구된다.