• Title/Summary/Keyword: 열역학

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Thermal-hydro-mechanical Properties of Reference Bentonite Buffer for a Korean HLW Repository (우리나라 고준위폐기물처분장 기준벤토나이트완충재의 열-수리-역학적 특성치)

  • Lee, Jae-Owan;Cho, Won-Jin;Kwon, Sang-Ki
    • Tunnel and Underground Space
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    • v.21 no.4
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    • pp.264-273
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    • 2011
  • Bentonite buffer is one of the major components of an engineered barrier for an HLW (High-Level Waste) repository. The bentonite buffer is significantly exposed to the decay heat from radioactive wastes, the inflow of groundwater from the surrounding rock of the repository, and the high swelling pressure of densely-compacted bentonite that comes in contact with the groundwater. Therefore, it is essential to understand the THM (Thermal-Hydro-Mechanical) behavior of the bentonite buffer and to acquire the input data of its related constitutive models for the performance and safety assessment of an HLW repository. This paper analyzed the THM properties which have been obtained by conducting laboratory tests with a candidate buffer material for a Korean HLW repository. Moreover the formulation recipe of the reference bentonite buffer was defined on the basis of functional criteria, thus suggesting the THM properties which correspond to the formulation recipe of the reference bentonite buffer.

Thermodynamics of Mixtures (I). Ideal Gases (혼합물의 열역학 (제1보). 이상기체)

  • C. K. Yun
    • Journal of the Korean Chemical Society
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    • v.17 no.5
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    • pp.324-331
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    • 1973
  • We study a mixture of ideal gases by use of recently developed methods in continuum thermodynamics of irreversible processes. A complete form of the free energy function and the gas law for each component are derived directly from an entropy production inequality by assuming that: (1) Constitutive functions depend on the mass densities, the diffusion velocities, the temperature and its gradient only. (2) Phenomenological coefficients appearing in an extra entropy flux are material constants. (3) The internal energy density per unit mass is independent of the total mass density (Joule).

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Study on Thermophysical Property Characteristics of a 4 Species Kerosene Surrogate in a Swirl Injector at Supercritical Pressure Condition (초임계 압력 조건 스월 인젝터에서 4개 화학종 혼합물 케로신 대체 모델의 열역학 물성 특성 연구)

  • Kim, Kukjin;Heo, Junyoung;Sung, Honggye
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.48-58
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    • 2013
  • Characteristics of thermophysical properties and flow structures in a swirl injector at supercritical pressure have been investigated using the kerosene surrogate consisting of four species and various ideal and real gas equations of state. The quantitative comparisons of thermophysical properties for equations of state have been performed. Also, a large eddy simulation and preconditioning technique for getting an effective convergence rate are applied to analyze turbulent flow in a swirl injector. The flow characteristics in the injector has significantly different behaviors depending on the equations of state due to the different thermophysical properties in the injector. The Redlich-Kwong-Peng-Robinson equation of state provides the most suitable results in the wide range of temperature.

A Performance Analysis of a Spark Ignition Engine Using Gasoline, Methanol and M90 by the Thermodynamic Second Law (가솔린, 메탄올, M90 연료를 사용한 전기점화기관에서의 열역학 제 2법칙적 성능해석)

  • Kim, S.S.
    • Journal of Power System Engineering
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    • v.13 no.6
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    • pp.22-28
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    • 2009
  • 열역학 제 2법칙의 관점의 열역학적 가용에너지인 엑서지 해석법을 적용하여 가솔린, 메탄올, M90 연료를 사용한 전기점화 기관의 성능해석을 수행하였다. 열역학적 사이클 해석을 위하여 사이클을 구성하는 각 과정은 열역학적 모델로 단순화하였고, 크랭크 각도에 따른 실린더의 압력과 작동유체를 구성하는 연료, 공기 및 연소생성물의 열역학적 물성 값들을 이용하여 각 과정에서의 엑서지와 손실 일을 계산하였다. 실험데이터는 단기통 전기점화기관을 가솔린, 메탄올과 M90(메탄을 90%+부탄 10%의 혼합연료)을 연료로 WOT(Wide Open Throttle), MBT(Minimum advanced spark timing for Best Torque), 2500rpm 조건으로 운전하여 측정하였다. 계산에 이용한 자료는 실험으로 측정한 크랭크 각도에 따른 연소실의 압력, 흡입공기와 연료유량, 흡입공기 온도, 냉각수 온도와 배출가스 온도 등이다. 이를 이용하여 각 과정에서의 엑서지와 손실 일을 계산하였으며 각 과정에서의 손실 일은 연소과정에서 가장 크며 팽창과정, 배출과정, 압축과정 및 흡입과정 순으로 크게 나타났다.

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Thermal-mechanical sensitivity analysis for the near-field of HLW repository (고준위 폐기물 처분장 near-field에 대한 열-역학적 민감도 분석)

  • 권상기;최종원;강철형
    • Tunnel and Underground Space
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    • v.13 no.2
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    • pp.138-152
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    • 2003
  • Three-dimensional computer modeling using FLAC3D had been carried out fur evaluating the thermal-mechanical stability of a high-level radioactive waste repository excavated in several hundred deep location. For effective modeling, a FISH program was made and the geological conditions and rock properties achieved from the drilling sites in Kosung and Yusung areas were used. Sensitivity analysis fer the stresses and temperatures from the modeling designed utilizing fractional factorial design was carried out. From the sensitivity analysis, the important design parameters and their interactions could be determined. From this study, it was found that deposition hole spacing is the most important parameter on the thermal and mechanical stability. The second and third most important parameters were disposal tunnel and buffer thickness.

Development of Molecular Simulation Software for the Prediction of Thermodynamic Properties (열역학 물성 예측을 위한 분자 시뮬레이션 소프트웨어의 개발)

  • Chang, Jaee-On
    • Korean Chemical Engineering Research
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    • v.49 no.3
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    • pp.361-366
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    • 2011
  • By using Monte Carlo simulation method we developed a new molecular simulation software which can be used to predict the thermodynamic properties of organic compounds. Starting from molecular structure and intermolecular potential function, rigorous statistical mechanical principles give a probability distribution for the behavior of a system containing many molecules, which enables us to calculate macroscopic thermodynamic properties of the system. The software developed in this work, cheMC, is based on Windows platform providing with easy access. One can efficiently administrate simulations by using an intuitive interface equipped with visualization tool and chart generation. It is expected that molecular simulations supplement the equation of state approach and will play a more important role in the study of thermodynamic properties.