유기 EL 성막 공정을 위한 점 증발원의 DSMC 시뮬레이션

전성훈,이응기,Jun, Sung-Hoon,Lee, Eung-Ki 한국반도체디스플레이기술학회 2010 반도체디스플레이기술학회지 Vol.9 No.3

The performance of an OLED fabrication system strongly depends on the design of the evaporation cell-source. Therefore, necessity of the preceding study for cell source development of new concept is becoming increase. A development plan to substitute for experiment is applied as use simulation. In this study interpret behavior of a particle through DSMC techniques, and in this paper presenting a form to make so as to have better performance of the pointtype cell source which had a nozzle.

DSMC 해석을 통한 유기 재료의 점성도 예측

전성훈,이응기 한국반도체디스플레이기술학회 2012 반도체디스플레이기술학회지 Vol.11 No.1

There have been plenty of difficulties because properties of Alq3 are unable to acquire in a process of manufacture of OLED. In this paper it will predict a viscosity of Alq3 through DSMC technique and suggest the way regarding a study to estimate properties of material through the computer simulation. There could generate errors of a simulation process in a vacuum deposition process since the properties of material that is used in a high- degree vacuum environment are not secured. Therefore, we would like to propose the new methods that can not only predict properties of a molecular unit but also raise an accuracy of simulation process by forecasting properties of Alq3.

Direct simulation of inhalable particle motion and collision in a standing wave field

Fengxian Fan,Xufeng Yang,Chang Nyung Kim 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

Motion of inhalable particles (PM10) under the effect of acoustic standing wave was numerically studied, and the inter-particle collision rate was investigated based on the direct simulation Monte Carlo (DSMC) method. The results show that the particles convergence rapidly, generating two particle number concentration peaks in a wavelength range along the wave propagation direction. Considering the inter-particle collision, it is found that when the particle size and number concentration keep constant, the collision rate first increases and then decreases with the increase of the frequency. Hence there is an optimal frequency that corresponds to the highest collision rate. As the sound intensity level increases, the collision rate increases monotonically. In cases with the same acoustic wave, the collision rate increases with the particle number concentration. The particle size is also an important factor that strongly affects the collision rate. The large inhalable particles collide more intensively than the small ones.

CFD/DSMC 혼합해석기법을 이용한 축대칭 천이영역 유동 해석

최영재(Young-Jae Choi),권오준(Oh-Joon Kwon) 한국항공우주학회 2019 韓國航空宇宙學會誌 Vol.47 No.3

본 연구에서는 희박기체 환경의 유동 정보를 효과적으로 계산하기 위해 CFD 해석기법과 DSMC 해석기법 간 연계 해석을 수행하는 CFD/DSMC 혼합해석기법을 개발하였으며, 개발된 해석기법을 이용하여 천이영역에서의 고속 비행체 주위 유동에 대한 해석을 수행하였다. 해석 형상으로는 콘과 실린더 형태로 이루어진 FRESH-FX 형상으로 고려하였고, 혼합해석기법의 결과는 순수 CFD 및 DSMC 해석 결과와 비교하였다. 천이영역의 대기가 상대적으로 희박하여 초음속 유동에서 발생하는 충격파의 구배 및 세기가 약화된 것을 확인하였다. 순수 CFD 해석 결과와는 차이를 보였고, 순수 DSMC 해석 결과와 거의 일치하는 결과를 도출하는 것을 확인하였다. 또한, 순수 DSMC 계산시간보다 해석 시간이 감소하였다. 이를 통해 혼합해석기법의 결과에 대한 신뢰성 및 해석 시간에서의 효율을 확인하였다. In the present study, a CFD/DSMC hybrid method performed by a coupled analysis between the CFD method and the DSMC method was developed to obtain the flow information on the rarefied gas flows effectively. Flow simulations around the high speed vehicles on the transition flow regimes were conducted by using the developed method. The FRESH-FX vehicle made of cone and cylinder shapes was considered for the simulations. The results of the hybrid method were compared with the results of the pure CFD and the pure DSMC method to confirm the reliability and efficiency of the hybrid method. It was found that the gradient and the intensity of the shock waves were weakened due to the relatively low density on the transition flow regime. It was confirmed that the results of the hybrid analysis were different to those of the pure CFD analysis and almost identical to those of the pure DSMC analysis. In addition, the computational time of the hybrid method was reduced than that of the pure DSMC method. As a result, it was obtained that the validity and the efficiency of the CFD/DSMC hybrid method.

로켓플룸의 DSMC해석

박재현(Jae Hyun Park),전우진(Woojin Jeon),백승욱(Seung Wook Baek),이지형(Ji Hyung Lee) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12

본 연구에서는 축대칭 DSMC 기법을 사용하여 로켓노즐에서 사출되는 플룸의 거동을 고도에 따라 분석하였으며, DSMC 결과들은 저고도에서의 연속체 해석결과와의 비교를 통하여 검증하고자 한다. The physical details of plumes exhausted from a rocket nozzle are investigated at various altitudes by employing axis-symmetric in-house DSMC code. DSMC results will be validated by comparing with the continuum analysis data at low altitude.

〈학술논문〉 몬테카를로 방법을 이용한 기체로 채워진 평판 사이의 마이크로 역열전달 해석

김선경(Sun Kyoung Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5

This work proposes an inverse method for estimating boundary temperature in a one-dimensional parallel domain filled with gas. The distance between the plates are considered submicron to one mm. The current problem assumes that both the heat flux and the temperature are simultaneously available on one boundary while no condition is known on the other boundary. The temperature on one of the boundaries should be inversely determined using the known temperature and heat flux. This study proposes a procedure for estimating the unknown boundary temperature based on the Monte Carlo simulation. Both the forward and inverse problems employ the Monte Carlo approach. The forward (direct) problem is solved by the direct simulation Monte Carlo while the inverse solution is obtained by the simulated annealing.

몬테카를로 방법을 이용한 기체로 채워진 평판 사이의 마이크로 역열전달 해석

김선경(Sun Kyoung Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.7

이 연구는 기체로 채워진 1 차원 평행 공간에서 경계 온도를 추정하는 역해석 기법을 제안한다. 평판사이의 거리는 마이크론 이하의 크기부터 1 밀리미터 까지를 고려한다. 한쪽 경계에서는 온도와 열유속이 동시에 활용 가능하지만 다른 경계에서는 아무런 측정이 불가한 상황을 가정한다. 한쪽 경계의 온도는 알려진 열유속과 온도를 이용하여 거꾸로 결정하여야 한다. 이 연구는 이 온도를 몬테카를로 모사를 통하여 산정하는 절차를 제안하였는데 직접 문제는 DSMC 를 사용하고 역문제는 모사 어닐링을 이용한다. This study proposes an inverse method for estimating the boundary temperature in a gas-filled, onedimensional parallel domain enclosed by parallel plates. The distance between the plates is considered submicron to one mm. In the current method, it is assumed that the conditions of both heat flux and temperature are simultaneously applicable to one boundary, while no conditions are applicable to the other boundary The temperature on one of the boundaries should be inversely determined from the known temperature and heat flux on the other boundary. This study proposes a procedure for estimating the unknown boundary temperature through Monte Carlo simulation. Both the forward and inverse problems employ the Monte Carlo approach. The forward (direct) problem is solved by using the direct simulation Monte Carlo while the inverse solution is obtained by the simulated annealing.

DSMC를 이용한 입자기반 2상유동 시뮬레이션

신영호(Yeongho Shin),전은지(Eunji Jun) 한국추진공학회 2023 한국추진공학회 학술대회논문집 Vol.2023 No.11

고도에 따른 로켓플룸의 형상변화 관찰

박재현(Jae Hyun Park),전우진(Woojin Jeon),백승욱(Seung Wook Baek) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5

본 연구에서는 축대칭 DSMC 기법을 사용하여 저고도와 고도도에서 플룸의 형상을 관찰하였다. 고도의 변화는 배압과 사출챔버의 전압의 비로 표현되며, 낮은 고도에서의 플룸은 Mach disk 등 복잡한 구조를 가지지만, 높은 고도에서의 플룸은 단순한 팽창만을 보여 주었다. The physical details of plumes exhausted from an orifice are in investigated with various altitudes by employing axis-symmetric DSMC. The change of altitudes are modeled by controling the ratio of back pressure to total pressure at chamber (Pb/P0). At low altitude (large Pb/P0), the plume has complicated structure including Mach disk whereas the plume at high altitude experiences plain expansion.

Simulation of Low-Pressure Capacitively Coupled Plasmas Combining a Parallelized Particle-in-Cell Simulation and Direct Simulation of Monte Carlo

Jin Seok Kim,Min Young Hur,In Cheol Song,Ho-Jun Lee,Hae June Lee IEEE 2014 IEEE transactions on plasma science Vol.42 No.12

<P>A parallelized particle-in-cell (PIC) simulation and direct simulation of Monte Carlo (DSMC) are combined to simulate low-pressure discharges. A two-dimensional (2-D) PIC simulation parallelized with graphics processing units is used to examine the discharge characteristics of a capacitively coupled plasma device at pressures <; 10 mTorr, whereas a DSMC method is used to calculate the neutral distribution instead of a fluid model. The neutral distribution profile is transferred to the PIC simulation as the initial condition. At low gas pressures, the neutral density profile shows nonuniform properties, which also changes the simulation results of plasma uniformity. Overall, the inclusion of an accurate neutral density profile is essential for obtaining exact simulation results that are comparable with the experimental results.</P>