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열영동 포집 방법을 이용한 층류 확산 화염내의 매연입자 크기측정
전지호,김상수 대한기계학회 1991 대한기계학회논문집 Vol.15 No.5
본 연구에서는 층류 확산화염내의 매연 분포에 관하여 좀 더 명확히 알아보고 자 화염의 높이방향 뿐만이 아니라 반경 방향으로도 매연을 열영동 포집하여 보았다. 한편, 화염 내에 삽입되는 Fig.1(a)와 같은 프로브에 매연 입자들이 열영동 현상에 의 하여 포집되려면 순간적인 돈도 구배가 필요하다. 따라서 화염내에서의 프로브 체류 시간을 조절할 수 있도록 Fig.1(b)와 같은 공압 장치(pneumatic device)를 만들어 실 험했다.
정체점 입자유동에서 복사열전달을 고려한 열영동 입자부착 연구
정창훈,이공훈,최만수,이준식,Jeong, Chang-Hun,Lee, Gong-Hun,Choe, Man-Su,Lee, Jun-Sik 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.5
A study of thermophoretic particle deposition has been carried out for a particle laden stagnation flow considering the effect of radiative heat transfer. Energy, concentration and radiative transfer equations are all coupled and have been solved iteratively assuming that absorption and scattering coefficients were proportional to the local concentration of particles. Radiative heat transfer was shown to strongly affect the profiles of temperature and particle concentration. e. g., radiation increases the thickness of thermal boundary layer and wall temperature gradients significantly. As the wall temperature gradients increase, the particle concentration at the wall decreases due to thermophoretic particle transport. The deposition rate that is thermophoretic velocity times particle concentration at the wall decreases as the effects of radiation increases. The effects of optical thickness, conduction to radiation parameter and wall emissivity have been determined. The effects of anisotropic scattering are shown as insignificant.
손민수(Minsoo Son),박미소(Miso Park),정혜진(Hyejin Jung) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
We have studied on a nanoparticle precipitator using thermophoretic force by temperature gradient. The deposition time of nanoparticles onto a substrate was computed by theoretical analysis and CFD methods, respectively. We analyzed the deposition time by two methods, and we notice of a particle motion and tendency. Also, we carried out experiments using simple apparatus and got the SEM images collected particles. As a result, we predicted a particle motion in the precipitator using theoretical equation and CFD and we designed the precipitator using design variables by this study.
배귀남,박승오,이춘식 대한기계학회 1994 대한기계학회논문집 Vol.18 No.1
To investigate thermophoretic effect on particle deposition, average deposition velocity toward a horizontal wafer surface in vertical airflow is measured keeping the wafer surface temperature different from the surrounding air temperature. In the present measurement, the temperature difference is maintained in the range from -10 to $4^{\circ}$ C Polystyrene latex (PSL) spheres of diameter between 0.3 and 0.8 .mu.m are used for the experiment. The number of particles deposited on a wafer surface is estimated from the measurements using a wafer surface scanner (PMS SAS-3600). Experimental data are compared with prediction model results.
외부증착공정에서의 열영동에 의한 입자부착에 관한 3차원 해석
홍기혁,강신형,Hong, Gi-Hyeok,Gang, Sin-Hyeong 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.3
Three-dimensional conjugate heat transfer and particle deposition on a circular cylinder in the OVD process are numerically investigated. Flow and temperature fields are obtained by an iterative method, and thermophoretic particle deposition is simulated. Effects of the heat conduction in the cylinder, the rotation speed of the cylinder, and the traversing speed of torch on the deposition are studied. Effects of variable properties are also included. As the conductivity of the cylinder decreases, particle deposition rate and deposition efficiency greatly decrease due to the reduced temperature gradient. The rotation of the cylinder has no significant effect on the deposition due to the small diameter of the cylinder and low speed of rotation. Since the increase of the torch speed keeps the surface low temperature, the particle deposition increases with the traversing speed.
최재혁(Jae-Hyuk Choi),한원희(Won-Hui Han),정석호(Suk Ho Chung) 한국마린엔지니어링학회 2007 한국마린엔지니어링학회 학술대회 논문집 Vol.2007 No.-
The characteristics of soot deposition on the cold wall in laminar diffusion flames have been numerically analyzed in a two-dimension with the FDS(Fire Dynamics Simulator). In particular, the effects of surrounding air temperature and wall temperature have been discussed. The fuel for the flame is ethylene (C₂H₄). Surrounding air temperatures are 300 K, 600 K, 900 K, 1200 K. Wall temperatures are 300 K, 800 K, 1100 K. The soot deposition length defined as the relative approach distance to the wall per a given axial distance is newly introduced as a parameter to evaluate the soot deposition tendency on the wall. The result shows that soot deposition length is increased with increasing the surrounding air temperatures and with decreasing the wall temperatures. The numerical results led to the conclusion that it is essential to consider the thermophoretic effect for understanding the soot deposition on the cold wall properly.
최재혁(Jae-Hyuk Choi),한원희(Won-Hui Han),정석호(Suk Ho Chung) 한국마린엔지니어링학회 2008 한국마린엔지니어링학회 학술대회 논문집 Vol.2008 No.-
The characteristics of soot deposition on the cold wall in laminar diffusion flames have been numerically analyzed in a two-dimension with the FDS(Fire Dynamics Simulator). In particular, the effects of surrounding air temperature and wall temperature have been discussed. The fuel far the flame is ethylene (C₂H₄). Surrounding air temperatures are 300 K, 600 K, 900 K, 1200 K. Wall temperatures are 300 K, 800 K, 1100 K. The soot deposition length defined as the relative approach distance to the wall per a given axial distance is newly introduced as a parameter to evaluate the soot deposition tendency on the wall. The result shows that soot deposition length is increased with increasing the surrounding air temperatures and with decreasing the wall temperatures. The numerical results led to the conclusion that it is essential to consider the thermophoretic effect for understanding the soot deposition on the cold wall properly.
균일 층류유동중에 있는 원형 실린더 주위의 열영동에 의한 입자 부착
홍기혁,강신형,Hong, Gi-Hyeok,Gang, Sin-Hyeong 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.2
Thermophoretic particle deposition on a circular cylinder in a uniform laminar air flow was numerically investigated using a control volume method based on the generalized non-orthogonal coordinate system. Variation of air properties due to the change of temperature was taken into account. Effects of variable property on the distribution of heat transfer and deposition rates of particle were discussed. A new correlation of thermophoretic particle deposition on a circular cylinder was proposed in the present study.