• Title/Summary/Keyword: Multi Nozzle

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Analysis on the Unsteady Reacting Flow-field in Integrated Rocket Ramjet (일체형 로켓 램제트의 비정상 반응유동장 해석)

  • Ko, Hyun;Park, Byung-Hun;Yoon, Woong-Sup
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1494-1498
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    • 2004
  • Transition sequence of rocket to ramjet was simulated numerically for a two-dimensional axisymmetric can-type ramjet engine. Multi-species preconditioned Navier-Stokes equations with $k-{\varepsilon}$ turbulence model and finite-rate chemistry model was employed. To calculate transition sequence, initial flow-field conditions for inlet diffuser with closed port-cover was computed first, and then that result was applied as initial conditions after port-cover opened. Terminal shock was developed as a result of increased pressure in a combustor due to combustion and ramjet operated at supercritical condition. For a smaller nozzle throat area, buzz instability was occurred. Strong pressure oscillations were observed as a result of forward and backward movement of terminal shock and those oscillations were not damped out.

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A STUDY OF QUALITY MONITORING SYSTEM FOR MANUFACTURING PROCESS AUTOMATION DURING LASER TAILORED BLANK WELDING

  • Park, Young-Whan;Park, Hyunsung;Sehun Rhee
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.606-611
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    • 2002
  • Welding using lasers can be mass-produced in high speed. In the laser welding, performing real-time monitoring system of the welding quality is very important in enhancing the efficiency of welding. In this study, the plasma and molten metal which are generated during laser welding were measured using the UV sensor and IR sensors. The results of laser welding were classified into five categories such as optimal heat input, little low heat input, low heat input, partial joining due to gap mismatch, and nozzle deviation. Also, a system was formulated which uses the measured signals with a fuzzy pattern recognition method which is used to perform real-time evaluation of the welding quality and the defects which can occur in laser welding.

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A study on the real time quality estimation in laser tailored blank welding (레이저 테일러드 브랭크 용접의 실시간 품질판단 및 통계프로그램에 관한 연구)

  • Park, Young-Whan;Rhee, Se-Hum;Park, Hyun-Sung
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.791-796
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    • 2001
  • Welding using lasers can be mass-produced in high speed. In the laser welding, performing real-time evaluation of the welding quality is very important in enhancing the efficiency of welding. In this study, the plasma and molten metal which are generated during laser welding were measured using the UV sensor and IR sensor. The results of laser welding were classified into five categories such as optimal heat input, little low heat input, low heat input, focus off, and nozzle change. Also, a system was formulated which uses the measured signals with a fuzzy pattern recognition method which is used to perform real-time evaluation of the welding quality and the defects which can occur in laser welding. Weld quality prediction program was developed using previous weld results and statistical program which could show the trend of weld quality and signal was developed.

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A Study on the Characteristics of Micro Deep Hole Machining in Micro Drilling Machine (마이크로 드릴링 M/C에 의한 미세구멍가공특성에 관한 연구)

  • 민승기;이동주;이응숙;강재훈;김동우
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.04a
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    • pp.275-280
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    • 2001
  • Recently, the trends of industrial products grow more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is requested more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multi-layered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. This paper shows the tool monitoring results of micro drill with tool dynamometer. And additionally, microscope with built-in monitor inspection show the relationship between burr in workpiece and chip form of micro drill machining.

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The Application of Cartesian Cut Cell Method for a High-Voltage GCB (분할격자법을 이용한 초고압 가스차단기 유동해석)

  • Lee Jong C.;Ahn Heui-Sub;Kim Youn J.
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.91-94
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    • 2002
  • It is important to develop new effective technologies for increasing the interruption capacity and reducing the size of a GCB (Gas Circuit Breaker). It is not easy to test the real GCB model in practice as in theory. Therefore, a simulation tool based on a CFD (Computational Fluid Dynamics) algorithm has been developed to facilitate an optimization of the interrupter. But the choice of grid is not at all trivial in the complicated geometries like a GCB. In this paper, we have applied a CFD-CAD integration using Cartesian cut-cell method, which is one of the grid generation techniques for dealing with complex and multi-component geometries.

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Sensitivity Analyses of Finite Element Method for Estimating Residual Stress of Dissimilar Metal Multi-Pass Weldment in Nuclear Power Plant (원전 이종 금속 다층 용접부 잔류응력 예측을 위한 유한요소 변수 민감도 해석)

  • Song, Tae-Kwang;Bae, Hong-Yeol;Kim, Yun-Jae;Lee, Kyoung-Soo;Park, Chi-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.9
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    • pp.770-781
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    • 2008
  • In nuclear power plants, ferritic low alloy steel components were connected with austenitic stainless steel piping system through alloy 82/182 butt weld. There have been incidents recently where cracking has been observed in the dissimilar metal weld. Alloy 82/182 is susceptible to primary water stress corrosion cracking. Weld-induced residual stress is main factor for crack growth. Therefore exact estimation of residual stress is important for reliable operating. This paper presents residual stress computation performed by 6" safety & relief nozzle. Based on 2 dimensional and 3 dimensional finite element analyses, effect of welding variables on residual stress variation is estimated for sensitivity analysis.

Characteristics of Ozonizers Manufactured in Energy & Environment Electromagnetic Lab. of Yeungnam University

  • Song, Hyun-Jig;Kim, Ki-Chai;Park, Won-Zoo;Lee, Kwang-Sik;Lee, Dong-In
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1999.11a
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    • pp.11-16
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    • 1999
  • Discharge characteristics research for high voltage and large current electric machinery design, the development of ozonizer with high yield and efficiency for environment improvement, generation of plasma & laser and EMI EMC are research fields of Enersy & Environment Electromagnetic Laboratory(EEEL) in the school of electrical & electronic engineering of Yeungnam University. On this paper, we would like to introduce the discharge and ozone generation characteristics of ozonizers designed and manufactured by EEEL. After starting research for fluid gas discharge characteristics early in the 1980's, high voltage nozzle(HVN) type ozonizer, neon lamp(Nelamp) type ozonizer, ozone lamp(Olamp) type ozonizer and multi-discharge type ozonizer(MDO) have been investigated since 1990.

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Design of Thermal Vapor Compressor by Numerical Analysis and Experimental Verification (전산해석을 통한 열증기압축기 설계와 실험적 검증)

  • Park, Il-Seouk;Park, Sang-Min;Ha, Ji-Soo
    • The KSFM Journal of Fluid Machinery
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    • v.8 no.6 s.33
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    • pp.33-39
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    • 2005
  • A thermal vapor compressor in which the subsonic/supersonic flow appears simultaneously, has been accurately designed through the CFD analysis for the various shape parameters such as the primary nozzle shape, converging duct shape, mixing tube diameter, and so on. The performance of the developed thermal vapor compressor has been experimentally verified to be installed in a Multi Effect Desalination(MED) plant as an important element. In this paper, the effects of each parameter are discussed on the basis of CFD results and the experimental results for various boundary conditions(motive pressure, suction pressure, and discharge pressure) are presented in compared with CFD results. The two results show a good agreement with each other within 2 % accuracy with regard to the entrainment ratio.

Performance Analysis of an Industrial Inkjet Printing Head Using the 1D Lumped Model

  • Sim, Won-Chul;Park, Sung-Jun;Joung, Jae-Woo
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.2
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    • pp.50-53
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    • 2008
  • A design approach using a one-dimensional (1D) lumped model was studied and applied to an industrial inkjet printing head design for micro patterning on printed circuit boards. For an accurate analysis, a three-dimensional piezoelectric-driven actuator model was analyzed and its jetting characteristics were applied to 1Danalysis model. The performance of the 1D lumped model was verified by comparing measured and simulated results. The developed 1D model helped to optimize the design and configuration of the inkjet head and could be implemented in the design of multi-nozzle inkjet printing heads to improve the jetting frequency and minimize crosstalk.

A Prediction of DI Diesel engine Performance using the Multizone Model (Multizone 모델을 이용한 직접분사식 디젤엔진 성능 예측에 관한 연구)

  • ;Liu Shenghua
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.1
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    • pp.40-47
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    • 2000
  • A model for the prediction of combustion and exhaust emissions of DI diesel engine has been formulated and developed. This model is a quasi-dimensional phenomenological one and is based on multi-zone combustion modelling concept. This model is developed based on the concept of Hiroyasu's multizone combustion models. It takes nozzle injection (spray) parameters, induction swirl into consideration and the models of zone velocity, air entrainment, fuel droplet evaporation and mixture combustion are upgraded. Various parameters, such as cylinder pressure, heat release rate, Nox and soot emission, and these parameters in the zone are simulated. The results are compared with the experimental ones, too.

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