• Title/Summary/Keyword: 표준유체

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Estimation of Fluid Saturations Using Agarose Standard in NMR Imaging (자기 공명 영상법에서 Agarose 표준 물질을 사용한 유체 포화도의 계산)

  • Kim, Kyung-Hoe
    • Applied Chemistry for Engineering
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    • v.10 no.1
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    • pp.160-165
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    • 1999
  • Agarose gels can be used as reference standards for the measurement of fluid properties in porous media because the relaxation properties of the gel reference standard and those of the fluid in porous media can be closely matched. The use of reference standard to determine porosity and saturation is discussed and the requirements for gel NMR properties given. The relaxtion times of agarose gels measured at 2.0 Tesla are illustrated as a function of agarose and paramagnetic impurity ($CuSO_4$) concentrations. This work shows an empirical result between agarose gel composition and gel relaxtion times. The average value for the porosity distribution is 17.7%, which compares well with the value calculated with the gravimetric analysis. Finally, two phase immiscible displacement using agarose gels as a reference standard was performed. The saturation profiles appear to be consistent with what one might calculate for a one-dimensional displacement in a uniform porous media.

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Prediction of Explosion Risk for Natural Gas Facilities using Computational Fluid Dynamics (CFD) (전산유체역학시뮬레이션을 이용한 도시가스 설비의 폭발위험성 예측)

  • Han, Sangil;Lee, Dongwook;Hwang, Kyu-Suk
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.3
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    • pp.606-611
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    • 2018
  • City natural gas is classified flammable hazardous gas and should be secured according to explosion risk assessment determined by Industrial Standard KS C IEC. In this study, leak size, ventilation grade and effectiveness were adopted to the KS C IEC for risk assessment in natural gas supply system. To evaluate the applicability of the computational fluid dynamics (CFD), the risk assessment was studied for four different conditions using hypothetical volume($V_z$) valuesfrom gas leak experiments, KS C IEC calculation, and CFD simulation.

Hydrodynamic Entrance Lengths and Entrance Correction Factors for a POWER-LAW Fluid in a Circular Duct (원관에서 POWER-LAW 유체의 수력학적 입구길이와 입구보정계수에 관한연구)

  • 오광석
    • The Korean Journal of Rheology
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    • v.7 no.3
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    • pp.261-266
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    • 1995
  • 원관에서 power-law 유체에 대하여 수력학적 입구길이와 입구보정계수를 측정할수 있는 새로운 방법이 개발되었다. 유변학적 성질을 측정할수 있는 긴관과 입구보정계수를 측 정할수 있는 짧은 관을 가진 새로운 모세관 점도계를 이용하여 증류수를 실험한 결과 유변 학적 성질과 입구 보정계수가 표준값과 비교하여 1%안의 오차를 얻었다. Power-law 유체 에 대한 해석 및 실험결과(Carbopol 960 용액)도 이미 보고된 값과 $\pm$6% 이내로 잘 일치하 였다.

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A Numerical Analysis on the Pressure Field Around KTX Train Using the Standard Framework of CFD Analysis for Railway System (철도시스템 전산유체해석 표준 프레임웍을 이용한 KTX 차량 주변 압력장에 대한 수치해석)

  • Nam, Sung-Won;Cha, Chang-Hwan;Kwon, Hyeok-Bin
    • Journal of the Korean Society for Railway
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    • v.9 no.5 s.36
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    • pp.511-516
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    • 2006
  • A standard framework of CFD(Computational Fluid dynamics) analysis for railway system has been developed to evaluate the overall aerodynamic performance of railway system and has been adopted to numerical simulation of the pressure field around KTX train. The framework is composed of standard aerodynamic model and standard aerodynamic performance to customize the general CFD solution process reflecting the characteristics of railway system such as various operation mode and performance factors. The results show that the standard framework of CFD analysis for railway system can provide objectivity and consistency to the CFD analysis for railway system and the pressure field around KTX train has been successively solved.

Development of a New Sensor with Divided Multiple Long and Short Wires in Transient Hot-wire Technique (다수의 분할된 긴 열선과 짧은 열선을 갖는 새로운 비정상열선법 센서개발)

  • Lee, Shin-Pyo;Lee, Myung-Hoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.5
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    • pp.510-517
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    • 2004
  • A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.