• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1494-1498
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• 2004

Transition sequence of rocket to ramjet was simulated numerically for a two-dimensional axisymmetric can-type ramjet engine. Multi-species preconditioned Navier-Stokes equations with $k-{\varepsilon}$ turbulence model and finite-rate chemistry model was employed. To calculate transition sequence, initial flow-field conditions for inlet diffuser with closed port-cover was computed first, and then that result was applied as initial conditions after port-cover opened. Terminal shock was developed as a result of increased pressure in a combustor due to combustion and ramjet operated at supercritical condition. For a smaller nozzle throat area, buzz instability was occurred. Strong pressure oscillations were observed as a result of forward and backward movement of terminal shock and those oscillations were not damped out.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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• pp.233-239
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• 1998

The effects of unsteady flow on gas turbine, particularly on a rotor blade surface are numerically investigated. The unsteady flow in a rotor blade passage as a result of wake/blade interaction is modeled by the inviscid flow approach, and solved by the Euler equations using a time accurate marching scheme, Numerical results show that for the case of $P_s/ P_r= 1.5$, the velocity and pressure distribution on the blade surfaces have much more complex profiles than those of $P_s/ P_r= 1.0$.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권7호
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• pp.326-331
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• 2005

We obtain analytical expressions the magnetic field of ferrites for DC magnetron sputtering device, which has been widely used for vacuum thin film deposition, and suggested the equation on maximum radius of the magnetic field by analytic solution. Also, the analytic results are compared with some calculations using magnetization elements of right-angled hexahedron.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.259-262
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• 2009

본 연구에서는 석탄광산 선탄장설비와 국소배기시스템의 일부를 모형화하여 포집특성과 유동특성실험을 수행하였으며 동일조건에서 수치해석을 수행하여 그 결과를 비교 검토하였다. case 5가 46.35%의 가장 높은 포집효율을 보였으며 실험의 3가지 변수 중 고무 커튼의 사용유무가 국소배기시스템의 포집효율에 가장 큰 영향을 미치는 것으로 판단된다. 또한 case 1, 5, 6에 대해 포집된 입자크기 확인 결과, 포집성능이 우수한 case 5가 입경 $20{\mu}m$ 초과 입자들이 약 55%로 가장 많이 포집된 것을 알 수 있었다. 따라서 제어거리는 0.5m 이상이 적절한 것으로 판단된다.

• 한국유체기계학회 논문집
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• 제11권4호
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• pp.38-44
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• 2008

This paper describes the performance and internal flow characteristics of two-stage high pressure ring blower. Chamber-type test rig is designed and manufactured for the performance test of the ring blower. Detailed flow characteristics inside the impeller and casing are analyzed by three-dimensional numerical simulation. Throughout numerical simulation, non-uniform inflow to the impeller inlet and reverse flow are observed near the inlet duct of the blower. This non-uniform inflow makes various recirculation flow inside the casing with the complicated shape of casing. Low velocity region is locally formed near the both sides of impeller outlet due to the non-uniform inflow to the impeller, thus deteriorates the performance of a ring blower.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1995년도 추계 학술대회논문집
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• pp.43-48
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• 1995

A numerical computation is carried out to analyse characteristics of flow fields around Air Supported Ships having arbitrary form. The computations are performed in a rectangular grid system with MAC(Marker And Cell) method. The governing equations are represented in a Finite Difference form by forward differencing in time and centered differencing in space except for convection terms. For validation of this numerical analysis method, the computation of flow fields around Catamaran and ACV(Air Cushion Vehicle) with pressure distribution on free surface are done, and that around Surface Effect Ship is also carried out. The results of the computations are compared with the those of existed numerical computation and experimental results with the same condition.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.479-486
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• 2010

Using the numerical code for the interior ballistics, the performance of the interior ballistics with the characteristics according to the position of the solid propellant in chamber has been investigated. In existing research, propellants have been evenly distributed in the chamber. In this study, however, several cases of the existence of empty space in the chamber at which the propellants are not evenly distributed are considered. The 7-perforated propellant configuration has been used in this research. The results have shown the change of performance of the interior ballistics according to solid propellant positions in the chamber.

• 한국전산유체공학회지
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• 제15권4호
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• pp.17-24
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• 2010

Using the numerical code for the interior ballistics, the performance of the interior ballistics with the characteristics according to the position of the solid propellant in chamber has been investigated. In existing research, propellants have been evenly distributed in the chamber. In this study, however, several cases of the existence of empty space in the chamber at which the propellants are not evenly distributed are considered. The 7-perforated propellant configuration has been used in this research. The results have shown the change of performance of the interior ballistics according to solid propellant positions in the chamber.

• 설비공학논문집
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• 제6권3호
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• pp.227-236
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• 1994

Steady flows of Newtonian and non-Newtonian fluids in the stenotic tubes with various stenotic shapes are numerically simulated. Validity of the modified power-law model as a constitutive equation for the purely viscous non-Newtonian fluid is discussed and the results of the power-law model are compared with those of the Carreau model, the Powell-Eyring model and experimental data for blood. Flow characteristics and reattachment lengths for non-Newtonian fluids in the stenotic tubes are presented extensively. Also, the analysis is extended to predict the influences of diameter ratio, stenosis spacing, number of stenosis and Reynolds number on the flow characteristics in the multiple stenotic tubes.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.381-385
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• 2009

This paper describes performance characteristics of a centrifugal fan having a different volute casing. The centrifugal fan has a backward blade type, and is used in a refuse collecting system. The flow characteristics inside the components are analyzed by three-dimensional Navier-Stokes analysis, and also compared to the results by experiments. Distributions of pressure and efficiency obtained by numerical simulation has a good agreement with the experimental results. Throughout the numerical simulation of the centrifugal fan, a fan efficiency is increased by decreasing local losses in the blade passage. It is found that the fan efficiency is enhanced by decreasing the distance between the shroud of a impeller and casing. Detailed flow analysis is also analyzed and discussed using the results obtained by numerical simulation.