• Title, Summary, Keyword: liquid pressurizing method

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Development of Textile Metal Matrix Composites for Electronic Packaging (전자 패키징용 직조형 금속복합재료 개발)

  • 이상관;김진봉;홍순형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.183-186
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    • 2000
  • A new textile metal matrix composite fur electronic packaging was developed and characterized. The thermal management materials consist of a plain woven carbon fabric as reinforcement and pure aluminum as matrix. The finite element method has been utilized in the analysis of thermal stress between the constituent components of packaging. The prototype part was manufactured by the liquid pressurizing method. The composite has CTE values of 4 to $5{\times}10^{-6}\;^{\circ}C^{-1}$10 in the range of $25^{\circ}C$ ~ 175$^{\circ}C$, resulting in good agreement with electronic materials such as Si and GaAs.

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Flow Visualization and Calculation at the Outlet of Propellant Tank Pressurizing Gas Injector (추진제탱크 가압용 인젝터 출구에서의 유동가시화 및 해석)

  • Kwon, Oh-Sung;Han, Sang-Yeop;Kwon, Ki-Jung;Chung, Yong-Cahp
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.1
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    • pp.73-79
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    • 2010
  • Propellant tank pressurizing gas injector is used in the pressurization system of liquid propellant rocket to reduce incoming gas velocity and distribute the gas in the tank. Temperature distribution in the propellant tank ullage is varied according to the gas injector shape, and it has influence on the required pressurant gas and thermal phenomena in the tank. In this paper, diffuser type gas injector was studied to make the ullage have stratified temperature distribution. Injected gas flow at the outlet of prototype diffuser was visulized using particle image velocimetry method and it was compared with the results of calculation. Calculation was well agreed with measurement and was used as an inlet condition of propellant tank ullage calculation.

The Hybrid Rocket Internal Ballistics with Two-phase Fluid Modeling for Self-pressurizing $N_2O$ I (자발가압 성질을 가진 아산화질소의 2상유체 모델링을 통한 하이브리드 로켓 내탄도 해석 I)

  • Lee, Jung-Pyo;Rhee, Sun-Jae;Woo, Kyoung-Jin;Oh, Ji-Sung;Jung, Sik-Hang;Moon, Hee-Jang;Sung, Hong-Gye;Kim, Jin-Kon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.45-49
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    • 2011
  • The blow-down oxidizer feed system with self-pressurizing $N_2O$ has more advantages than the regulated system. However, it is difficult to predict the exhaust flow rate because there exist two phases in the $N_2O$ tank - liquid phase and gas phase, and the properties of $N_2O$ in storage tank are varied continuously during blow-down. In this paper, a method that can analyse simply the blow-down oxidizer feed system is studied. The properties of saturated $N_2O$ are found from the NIST data base, and mass flow through the orifice is modeled as NHNE. Cold flow test with hybrid rocket combustor is performed for the comparison where the results should found from the good agreement.

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Characterization of Acoustic Emission Signal for Welding Flaw and Stress Corrosion of SPPH Steels (SPPH강의 용접결함과 응력부식에 따른 음향 방출 신호의 특성)

  • Kim, Sung-Dai;Jung, Woo-Gwang;Lee, Jong-O;Jung, Yu-Jin
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.97-104
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    • 2007
  • An investigation has been made on the relationship between characteristics of Acoustic Emission (AE) signal in welding flaw and the stress corrosion defect in-service for the high pressure pipe steel. In order to tackle the problem of welding flaw in high pressure pipe, specimens were made by the aid of the application of both corrosion liquid usage and a quenching method after local heating. The amplitude of signal was $60{\sim}75\;dB$ in the territory which is suspected for defect, and the specimens which only have welding flaw showed gradients of 0.034, 0.034, 0.035. Moreover, there is a certain increase in gradient even though the differences are very slight. That is, corrosion specimens showed new gradients of 0.040, 0.039, 0.041 which put welding flaw and corrosion mechanism together. After pressurizing 3 minutes, AE signal has been detected from welding flaw easily in each part of the section. It is possible to predict the occurrence and also prevent the damage of stress corrosion crack which has characteristics of cleavage fracture.