• 유체기계공업학회:학술대회논문집
• /
• 2002.12a
• /
• pp.489-492
• /
• 2002

The objective of the present study were to measure the viscosities of non-Newtonian fluids by the transient flow concept in a capillary tube and to apply to hemodynamic studies and pump performance evaluations. The developed capillary tube viscometer could be used to measure the viscosities of the non-Newtonian fluids for a wide range of the shear rate by a run of experiment in a very short time interval. The measured viscosities of water and blood fur different shear rates were good agreement with those of the well established data. The measured viscosities for muddy water varied with the shear rates.

• The Korean Journal of Rheology
• /
• v.9 no.3
• /
• pp.103-110
• /
• 1997

고분자 복합재료 제조방법의 하나인 수지이동성형의 충전공정을 모사하기 위한 수 치모사 코드를 개발하였다. 수지이동성형의 충정공정문제를 수학적 공식으로 표현하기 위하 여 비등방성 다공질체를 통과하는 유동에 대한 이론을 사용하였다. 과도상태로 진행하는 자 유표면의 동적 충전거동을 묘사하기 위하여 수치격자 생성을 포괄하는 경계적합 좌표계의 계산기법을 적용하였다. 이와 아울러 불규칙적인 구저와 다중으로 연결된 금형면의 충전모 사에 저합한 복합격자의 개념을 도입하였다. 복합격자들 간의 가상의 경계에 대해서는 검사 체적 기법을 이용하여 물질보존을 만족시켜 주었다. 임의의 금형 두께와 투과도를 가지는 다수의 금형면이 결합된 두 개의 입구를 지닌 금형을 대상으로 하여 몇가지 예를 시험해 보 았다. 수치모사의결과 복합격자의 개념을 도입한 수치모사 코드는 수지이동성형의 복잡한 충전공정을 보다 정교하게 모사하는데 응용될수 있음을 보여주었다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.05a
• /
• pp.596-602
• /
• 1998

한국의 차세대 원자로 (Korean Next Generation Reactor; KNGR)에 처음 적용되는 격납건물내에 설치된 재장전수조 (In-Containment Refueling Water Storage Tank; IRWST)는 기존 재장전수조의 기능외에 주입모드에서 재순환 모드를 전환생략, 일차계통으로 방출된 고온, 고압 냉각수의 응축 및 냉각 격납용기 방사능 오염방지, 원자로 동공층수 등 여러 가지 추가 기능을 가진 한층 진보된 설계개념이다. 발전소 천이사고 시 발생하는 Pipe Clearing, 응축진동 현상(Condensation Oscillations), Chugging 등의 열수력 현상들이 방출증기의 유동 및 가속도와 관련해 항력과 응력, 압력진동 등을 일으켜 IRWST 구조물에 영향을 미칠 수 있기 때문에 IRWST를 처음으로 시도하는 우리 나라로서는 이와 관련된 제반현상에 대한 심도 깊은 연구가 요구된다. 따라서 본 연구에서는 원자력 발전소 과도로 인한 가압기 안전밸브(Pressurizer Safety Valve) 또는 안전감압밸브(Safety Depressurization Valve) 작동시 IRWST로 방출되는 유체로 야기되는 하중 예측 모델을 기존의 BWR의 응축수조(suppression Pool)에서 일어나는 각종 현상을 토대로 이론적으로 체계적으로 유도하여 이를 비교, 분석하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.11
• /
• pp.5371-5376
• /
• 2013

The role of a main starting air valve is to supply compressed air to the diesel engine for starting the stopped diesel engine of a ship and cut off the air during normal operation. In this study, the main starting air valve with 80mm size was designed based on the developed valve with 50mm size. The concept design of the 80A main starting air valve was completed by using CATIA. Then, fluid analysis was performed to investigate the flow characteristics such as pressure and velocity distribution. Sequentially, structural analysis using FSI was performed. In this study, ANSYS CFX and ANSYS Workbench are utilized. The heavy weight of the body can deteriorate the strength performance of neighbor elements, leading to undesirable effect on flow characteristics. Thus, in this research, a lightweight design of the body was suggested satisfying strength requirement. The weight of the suggested design was reduced by 7kg, and the strength satisfied its requirement.

• Journal of Energy Engineering
• /
• v.28 no.4
• /
• pp.103-110
• /
• 2019

The domestic innovative power reactor named iPOWER will employ the passive molten corium cooling system(PMCCS) to cool down and stabilize the core melt in the severe accident. The final design concept of the PMCCS is yet to be determined, but the in-vessel retention through external reactor vessel cooling has been also considered as a viable strategy to cope with the severe accident. In this study, the two-phase natural circulation flow established between the reactor vessel and the insulation was simulated using a thermal-hydraulic system code, MARS-KS. The flow path of cooling water was modeled with one-dimensional nodes, and the boundary condition of the heat load from the molten core was defined to estimate the naturally-driven flow rate. The evolution of major thermal-hydraulic parameters were also evaluated, including the temperature and the level of cooling water, the void fraction around the lower head of the reactor vessel, and the heat transfer mode on its external surface.

• Fire Science and Engineering
• /
• v.20 no.3 s.63
• /
• pp.65-70
• /
• 2006

From the beginning of the construction stage, the fire protection regulation for the nuclear power plants conforms to the design requirements for the acquisition of the license permit. This regulation is based on the plant status of the normal operation, but it is not enough to be used as an application standard for fire protection at the transient mode of the plant and the outage time for refueling as well as for the plant decommissioning. While the advanced fire protection requirement that has been developed in America recently suggests the performance-based requirement and management rule applicable to the overall life time of the plant, it simply represents the conceptual application. It means that it can not be treated as appropriate standards because it does not deal with the qualitative and quantitative approach in specific ways. By the way, with the use of the performance-based fire risk analysis, the dynamic behavior of the heat and smoke at the fire compartment of the nuclear power plants can be analyzed and the thermal effect to the safety-related equipment and cables can be evaluated as well. At this paper, it suggests the ways to change the applicable fire protection regulations and the required evaluation items for the fire risk resulted from the plant configuration change with an intent to introduce the state-of-the-art quantitative fire risk analysis technology at the domestic nuclear power plants.