• Korean Chemical Engineering Research
• /
• 제49권3호
• /
• pp.361-366
• /
• 2011

몬테칼로 시뮬레이션 방법을 사용하여 유기화합물의 열역학적 물성을 예측하는 새로운 분자 시뮬레이션 소프트웨어를 개발하였다. 분자 구조, 분자간 포텐셜 에너지 함수와 엄밀한 통계역학적 원리로부터 많은 분자들을 포함한 계의 거동에 대한 확률 분포를 구하고 거시적인 계의 열역학적 물성을 계산한다. 본 연구에서 개발된 소프트웨어 cheMC는 윈도우즈 플랫폼에 기반하여 사용자 접근성이 좋고, 가시화 도구 및 차트 생성 기능 등 직관적인 인터페이스로 시뮬레이션 관리가 쉽다. 분자 시뮬레이션은 기존의 상태 방정식을 사용한 열역학 물성 연구를 보완하고, 향후 그 역할이 점점 더 커질 것으로 기대된다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.256-260
• /
• 2003

A computer program to calculate thermodynamic properties of oxygen is developed. Procedures for the calculation is briefly discussed. The program calculates unknown thermodynamic properties fixing the state with two independent input properties. If input value by user is inappropriate, it displays an error message. In addition user can change units with easy. The program developed in this work can be utilized to calculate parameters required for the simulation and design of an equipment using oxygen.

• Journal of applied mathematics & informatics
• /
• 제26권3_4호
• /
• pp.519-530
• /
• 2008

This paper studies the multi-domain coupled system of one dimensional Arctic temperature field and establishes identification model about the thermodynamic parameters of sea ice (heat storage capacity, density and conductivity) by the so-called output least-square estimate according to the temperature data acquired by a monitor buoy installed in the Arctic ocean. By the optimal control theory, the existence and dependability of weak solution and the identifiability of identification model have been given. Moreover, necessary optimality condition is proposed. Furthermore, the optimal algorithm for the identification model is constructed. By using the optimal thermodynamic parameters of Arctic sea ice, the numerical simulation is implemented, and the numerical results of temperature distribution of Arctic sea ice are demonstrated.

• 한국태양에너지학회 논문집
• /
• 제23권4호
• /
• pp.45-54
• /
• 2003

For cooling of double effect absorption heat pump system of solar heating source, analysis of thermodynamic design data has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data, enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture ($H_2O$ : CHO ratio 10:1 by mole) by computer simulation are done. The obtained results, COP and mass flow ratio of the water - lithium bromide - ethylene glycol system, are compared with data for the water-Libr pair solution.

• 한국태양에너지학회 논문집
• /
• 제22권4호
• /
• pp.51-61
• /
• 2002

Analysis of thermodynamic design data of double effect solar absorption heat pump system for heating has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data. enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture (H2O: CHO ratio 10:1 by mole) by computer simulation. The obtained results, COP and mass flow ratio of the water-lithium bromide-ethylene glycol system, are compared with data for the water-Libr pair solution.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1667-1671
• /
• 2003

A computer program to calculate properties of nitrogen is developed. Procedures for the calculation is briefly discussed. The program calculates unknown thermodynamic properties fixing the state with two independent input properties. If input value by user is inappropriate, it displays an error message and replaces the input value with an appropriate one. In addition user can change units with easy. The program developed in this work can be utilized to calculate parameters required for the simulation and design of an equipment using nitrogen.

• 에너지공학
• /
• 제24권3호
• /
• pp.55-60
• /
• 2015

Recent engine development has focused mainly on the improvement of engine efficiency and output emissions. The improvements in efficiency are being made by friction reduction, combustion improvement and thermodynamic cycle modification. Computer simulation has been developed to predict the performance of a spark ignition engine. The effects of various cylinder pressure, heat release, flame temperature, unburned gas temperature, flame properties, laminar burning velocity, turbulence burning velocity, etc. were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion model for a spark ignition engine running with isooctane as a fuel and predicting its behavior.

• Bulletin of the Korean Chemical Society
• /
• 제18권5호
• /
• pp.501-509
• /
• 1997

In recent papers[Bull. Kor. Chem. Soc. 1996, 17, 735; ibid 1997, 18, 478] we reported results of molecular dynamics (MD) simulations for the thermodynamic, structural, and dynamic properties of liquid normal alkanes, from n-butane to n-heptadecane, using three different models. Two of the three classes of models are collapsed atomic models while the third class is an atomistically detailed model. In the present paper we present results of MD simulations for the corresponding properties of liquid branched-chain alkanes using the same models. The thermodynamic property reflects that the intermolecular interactions become weaker as the shape of the molecule tends to approach that of a sphere and the surface area decreases with branching. Not like observed in the straight-chain alkanes, the structural properties of model Ⅲ from the site-site radial distribution function, the distribution functions of the average end-to-end distance and the root-mean-squared radii of gyration are not much different from those of models Ⅰ and Ⅱ. The branching effect on the self diffusion of liquid alkanes is well predicted from our MD simulation results but not on the viscosity and thermal conductivity.

• 한국자동차공학회논문집
• /
• 제1권1호
• /
• pp.80-89
• /
• 1993

Performance simulation for a Spark Ignition Wankel rotary Engine is presented in this paper. The volume of chamber at each eccentric shaft angle is evaluated by using geometric models of housing and rotor. A thermodynamic model which includes the first law of thermodynamics, combustion and convective heat transfer from chamber contents to surroundings is imployed. A thermochemical equilibrium model which considers 10 species(CO, $CO_2$, $O_2$, $H_2$, $H_2O$, OH, O, NO, $N_2$) in the burned gas region, is also employed. Four processes of gas exchange, compression, combustion and expansion are considered and the pressure, temperature and composition of chamber gas at each eccentric shaft angle in each process are computed in this performance simulation. This performance simulation must be useful for optimal design of Spark Ignition Wankel Rotray Engine with parametric study for various design parameters and operating conditions.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년 영문 학술대회
• /
• pp.499-502
• /
• 2008

This paper presents on research findings of how Visual C++ program can be used to generate codes capable of performing ramjet engine simulation To understand the diversity and applicability of this tool an arbitrary ramjet model will be considered for which generated output values will be compared with those from a commercial program GASTURB 9 iterated under the same input parameters. Several governing thermodynamic equations will first be discussed in order that we understand the fundamental idea behind values printed out on the GUI. C++ compiler was chosen as a tool of use due to its availability, ease of use, ability to compute functions faster and uniquely possible to make a stand alone GUI executable in DOS mode. The program is developed in such a way that given the ambient flight conditions, burner exit temperature and several geometry areas the program generates its own input values used in the succeeding stations. A close resemblance of output values that define performance and thermodynamic state of the engine was realized between GASTURB 9 and using this code made from C++ compiler.