• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.211-216
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• 2005

The authors carried out experiment, Computer Fluid Dynamics(CFD) and energy simulation of simulator. As a results of experiment and CFD, diffuser velocity is very important design factor for occupied zone air conditioning in Under Floor Air Distribution(UFAD) system. Then, in contrast to energy consumption of the Overhead system, the UFAD system could reduce 6.4% of the total energy because of occupied tone air conditioning. It concluded that tile UFAD system is more effective in energy Performance than the Overhead system.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3291-3296
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• 2010

A gelastatins (1), natural MMP inhibitors, and their hydroxamate analogues (2) in TACE enzyme evaluated for discovery of potent TACE inhibitors. We have employed molecular dynamics simulations to compute the relative free energy of hydration and binding to TACE for gelastatin (1) and its hydroxamate analogue (2). The relative free energy difference is directly described in this article using the free energy perturbation approach as a means to accurately predict the TACE inhibitor of gelastatin analogues. The results show that the good agreement between the experimental and theoretical relative free energies of binding, gelastatin hydroxamate (2) binds stronger to TACE by -3.37 kcal/mol. The desolvation energy costs significantly reduced binding affinity, hydroxamate group associated with high desolvation energy formed strong favorable interactions with TACE with more than compensated for the solvation costs and therefore led to an improvement in relative binding affinity.

• 대한전기학회논문지
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• 제43권5호
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• pp.693-702
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• 1994

This paper deals with direct voltage stability analysis using a power system energy function. The structure preserved energy function is proposed as an energy function for voltage stability analysis. With the use of the proposed energy function voltage collapse conditions are derived, which yields the exactly same results with the Jacobian matrix approach. The voltage collapse phenomenon is analyzed by several methods, which shows that all of the methods produce the same voltage condition. This study also investigates the voltage collapse dynamics by using the proposed energy function. As a result, it has been found that the voltage collapse can be classified into two categories: static and dynamic instablilties which have quite different behaviors. In addition a new method is presented to calculate the power capacity limit of transmission lines with respect to voltage stability. The proposed method is tested for a 2-bus sample system, which shows the characteristics of voltage collapse phenomenon via the energy function.

• Current Applied Physics
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• 제18권12호
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• pp.1528-1533
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• 2018

The trajectories of adsorption and dissociation process of $O_2$ on the Al (111) surface were studied by the spinpolarized ab initio molecular dynamics method, and the adsorption activation energy was clarified by the NEB method with hybrid functionals. Three typical dissociation trajectories were found through simulation of $O_2$ molecule at different initial positions. When vertically approaches to the Al surface, the $O_2$ molecule tends to rotate, and the activation energy is 0.66eV. If $O_2$ molecule does not rotate, the activation energy will increase to 1.43 eV, and it makes the O atom enter the Al sublayer eventually. When the $O_2$ molecules parallel approach to the Al surface, there is no activation energy, due to the huge energy released during the adsorption process.

• 한국분무공학회지
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• 제29권1호
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• pp.1-6
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• 2024

This paper is a numerical analysis study for evaluating the energy efficiency of electric vehicles. Currently, the methods for testing and evaluating the energy consumption efficiency of electric vehicles have limitations such as resources and time. Therefore, there is a need for research on developing models to predict the energy consumption efficiency of electric vehicles. In this study, a numerical analysis research is conducted to predict the energy efficiency of electric vehicles using a vehicle dynamics numerical analysis model. To validate the accuracy of the simulation model, it is compared the results of dynamometer tests with the simulation results and used the Unified Diagnostic Services (UDS) protocol to acquire internal data from the electric vehicle. It is ensured the reliability of the simulation model by comparing data such as motor speed, battery voltage, current, state of charge (SOC), regenerative braking power generation, and total driving distance of the test vehicle with dynamometer test data and simulation model results.

• 대한기계학회논문집A
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• 제37권2호
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• pp.257-263
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• 2013

본 논문에서는 파력에너지를 전기에너지로 변환시키는 파력발전기를 다물체 동역학을 이용하여 모델링 하였으며, 계류시스템이 부유식 파력발전기에 미치는 영향에 대해서 분석하였다. 계류시스템이 파력발전기에 미치는 영향을 줄이기 위한 연구가 많이 이루어지고 있다. 구속방정식과 힘 요소를 이용하여 다물체 시스템을 모델링 하였으며, 3 차원 파랑하중을 적용하여 부유체에 작용하는 파력을 모델링 하였다. 파력발전기의 거동과 발전량을 분석하기 의해 상용 다물체 동역학 해석프로그램인 MSC/ADAMS 를 이용하였다. 계류시스템이 있을 때와 없을 때의 결과를 비교하였고, 특히 극한 파랑하중이 작용했을 때의 시뮬레이션을 통해 파력발전기의 안정성을 평가하였다.

• 한국안전학회지
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• 제30권1호
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• pp.14-20
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• 2015

A Large Eddy Simulation(LES) was performed for the prediction of unsteady dispersion behavior of hydrogen fluoride (HF). The HF leakage accident occurred at the Gumi fourth industrial complex was numerically investigated using the Fire Dynamics Simulator (FDS) based on the LES. The accident area was modeled three-dimensionally and time-varying boundary conditions for wind were adopted in the simulation for considering the realistic accident conditions. The Message Passing Interface (MPI) parallel computation technique was used to reduce the computational time. As a result, it was found that the present LES simulation could predict the unsteady dispersion features of HF near the accident area effectively. The dispersion behaviors of the leaked HF was much affected by the unsteady wind direction. The LES could predict the time variation of the HF concentration reasonably and give an useful information for the risk analysis while the prediction with the time-averaging concept of HF concentration had a limitation for the amount of HF concentration at specific location point. It was identified that the LES is very useful to predict the dispersion characteristics of hazardous chemicals.

• 터널과지하공간
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• 제22권3호
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• pp.188-195
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• 2012

본 연구에서는 전산유체역학 코드인 FLUENT를 이용하여 열에너지 지하 저장을 위한 최초의 대규모 암반공동인 스웨덴 Lyckebo 저장소의 열성층화 거동을 분석하였다. 열에너지의 반복적인 저장 및 생산으로 인한 주변 암반의 히팅이 열성층화와 열손실에 미치는 영향을 분석하기 위해 암반의 온도조건을 달리하여 열전달 해석을 수행하였으며, 성층화 지수를 토대로 열에너지 저장 후 시간경과에 따른 열성층화의 변화를 정량적으로 분석하였다. 분석결과, 주변 암반이 히팅되지 않은 저장공동의 초기 운영단계에서는 시간경과에 따라 저장된 열에너지의 성층화가 빠르게 저하되는것으로 나타났으며, 저장공동의 운영기간이 늘어남에 따라 주변 암반의 히팅으로 인해 열성층화의 변화 및 열손실이 줄어드는 것을 확인하였다.

• 한국태양에너지학회 논문집
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• 제33권5호
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• pp.105-112
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• 2013

The new renewable energy became popular as a clean and sustainable alternative energy under the circumstances that the entire world is facing severe abnormal climate due to the use of fossil fuel, and among which, solar energy can be obtained anywhere and is not difficult to apply it into the existing buildings, which makes it possible to be widely distributed. However, as PV module is installed into a single plate system, it shows structural weaknesses which are vulnerable to wind load and give loss to design elements in external appearance. Accordingly, this study planned one-step parallel system to complement the problems occurring from a single plate system and used STAR-CCM+ V.8 made by CD-Adapco, a computational fluid dynamics(CFD) simulation tool to measure wind load stability and support based on the design standards for a single plate system and one-step parallel system. Building height was limited to less than 10m and wind speed was given when increasing from 35m/s to 50m/s by 5m/s on PV system installed into the flat roof. In this case, our analysis suggested that step-one parallel system was in class 7-9 according to Beaufort's wind power classification, which did not have an impact on the fixed PV system, and the single plate system is considered to cause risks in designing wind speed in central districts because it is more than wind power class 12.

• Bulletin of the Korean Chemical Society
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• 제18권12호
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• pp.1274-1280
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• 1997

The photodissociation dynamics of CH2I2 has been studied at 304 nm by state-selective photofragment translational spectroscopy. Velocity distributions, anisotropy parameters, and relative quantum yields are obtained for the ground I(2P3/2) and spin-orbit excited state I*(2P1/2) iodine atoms, which are produced from photodissociation of CH2I2 at this wavelength. These processes are found to occur via B1 ← A1 type electronic transitions. The quantum yield of I*(2P1/2) is determined to be 0.25, indicating that the formation of ground state iodine is clearly the favored dissociation channel in the 304 nm wavelength region. From the angular distribution of dissociation products, the anisotropy parameters are determined to be β(I)=0.4 for the I(2P3/2) and β(I*)=0.55 for the I*(2P1/2) which substantially differ from the limiting value of 1.13. The positive values of anisotropy parameter, however, show that the primary processes for I and I* formation channels proceed dominantly via a transition which is parallel to I-I axis. The above results are interpreted in terms of dual path formation of iodine atoms from two different excited states, i.e., a direct and an indirect dissociation via curve crossing between these states. The translational energy distributions of recoil fragments reveal that a large fraction of the available energy goes into the internal excitation of the CH2I photofragment; < Eint > /Eavl=0.80 and 0.82 for the I and I* formation channels, respectively. The quantitative analysis for the energy partitioning of available energy into the photofragments is used to compare the experimental results with the prediction of direct impulsive model for photodissociation dynamics.