• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.34-37
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• 2009

본 연구에서는 액체로켓 엔진용 재생냉각 추력실 내부에서 일어나는 연소와 냉각 과정을 통합된 방법으로 해석함으로서 초기 설계 단계에서 추력 성능, 냉각 특성, 무게 및 크기 간의 trade-off를 수행할 수 있는 수치해석 절차를 제시하였다. 또한 형상 설계, 성능 분석, 냉각 해석과 종합적인 설계 평가를 수행한 실제 적용 사례를 통해 설계 도구로서의 활용도와 신뢰도를 평가하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.163-166
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• 2009

본 연구에서는 추진기관 탄자 및 파편 충격시험을 실시하여 그 특성을 분석 평가 하였다. 연소관은 카본 에폭시 복합재를 사용하였고 추진제는 둔감 특성을 향상 시켜주기 위해 HTPE 추진제를 사용하였다. 반응 형태를 정량적으로 판단하기 위해 음압 및 열유속 센서를 사용하였다. 탄자 및 파편 시험한 HTPE 모타들의 반응형태는 Type V 인 연소반응을 나타내었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.587-590
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• 2000

The new core making method economized on core sand requested. The new method is heating core box until it reaches reasonable temperature and then spraying core sand with core binder into core box. Inner temperature distribution have to uniform in order to form core of uniform thickness. Therefore, in this study we treat of inner temperature distribution of core box in priority. First, determine proper torch number. Next, optimize the torch position to minimize the average of absolute deviation(AVEDEV) of inner temperature. The results are as followed : 1. The torch number that makes inner temperature distribution about $300^\circ{C}$ uniformly is 25. 2. When $S_H$ and $S_V$ is 0.7, the torch position is optimized and AVEDEV is 5.85.

• 대한기계학회논문집
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• 제14권2호
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• pp.484-491
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• 1990

A heat-flux meter has been designed and manufactured to measure the heat flux from the flame. A calibration method of the heat-flux meter by a calibration furnace has also been proposed. The k-type (Chromel-Alumel) thermocouple material has been used as the material for the beat-flux meter. The electormotive force (e.m.f.) from the K-type thermocouple is shown to be linearly proportional to the heat flux absorbed. The characteristics of the heat-flux meter become better as the radius of heat absorbing disk becomes larger and its thickness thinner.

• 대한기계학회논문집
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• 제18권9호
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• pp.2454-2462
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• 1994

The effects of thermal stratification on the flow of a stratified fluid past a heated circular cylinder were examined in a wind tunnel. Turbulent intensities, rms values of temperature and turbulent convective heat flux distributions in the heated cylinder wake with and without thermal stratification were measured by using a hot-wire and cold-wire combination probe. A phase averaging method was also used to estimated coherent motion in the near wake. It is found that the vertical turbulent motion in the stably stratified flow case dissipates faster than that of the neutral case, i.e., vertical growth of vortical structure is suppressed under the strongly stratified condition. The coherent motion of temperature makes a large contribution like velocity coherent motion. However, the coherent motions of temperature fluctuation become very different with the change of experimental conditions, though the velocity coherent motions are quite similar in all experimental conditions.

• Journal of Advanced Marine Engineering and Technology
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• 제36권6호
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• pp.774-779
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• 2012

MILD(Moderate and Intense Low Oxygen Dilution) 연소는 연소 가스의 재순환을 이용하여 고온 형성을 최대한 억제하고 질소산화물의 발생을 저감하는 동시에 연소로의 내부 온도 균일화를 통한 열 이용 효율을 향상시킬 수 있는 연소기술이다. 본 연구에서는 원추형 연소로에서 연료 유량은 고정하고 공기 유량으로 당량비(${\Phi}$)를 조절하고 배기가스를 측정하여 MILD 연소특성을 도출하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1372-1377
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• 2003

The stabilization of propane/air lean premixed flames by a heated cylindrical rod is investigated experimentally. The flame stability limits, heat flux, surface temperatures, equivalence ratios, and mixture velocities are measured in order to understand the role of heat flux or surface temperature on the flame stabilization of lean premixed flames. The flame stability limits are lowered by a heated cylindrical rod and extended even below the flammability limit of propane/air mixture when sufficient heat flux is provided. The flame stability limit decreases with the increase of heat flux or surface temperature and decreases with the higher mixture velocity. The diameter of cylindrical rod, however, dose not significantly affect the flame stability limit. The laminar flame speed has been measured for ultra lean propane/air premixed flames. The flame stabilization by a heated cylindrical rod provides the useful tool for the measurement of flame speed under very fuel-lean conditions.

• 한국생산제조학회지
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• 제22권2호
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• pp.228-234
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• 2013

This study focuses on development of a finite element model for analysis of thermal characteristics of a direct-connection spindle of a machining center by joint simulation of heat transfer and thermal deformation. Two finite element analyses were carried out procedurally for heat transfer, first, to identify temperature distribution of components of the spindle and then for thermal deformation to identify their structural behavior based on the temperature distribution. It was assumed that the heat transfer between a component revolving and the surrounding air is identical to that between a flat plate and the running air on it and the heat transfer is based on a uniform surface heat flux for turbulent flow. The results from the analyses were compared with those from experiments to validate the finite element model.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.80-83
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• 2004

This experiment has been carried out to measure the process of droplet formation between water phase fluid$(PVA\;3\%)$ and organic phase fluid(oil), Internal and External flow fields measured by a Dynamic Micro-PIV method Water-in-oil(W/O) droplets successfully generated at a cross junction and Y junction. Internal and external flow fields were measured when the droplet grew up, stretched and separated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.725-728
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• 2002

A separate type thermosyphon can be utilized as a cooling device of electronic equipments (such as CPU of a personal computer or notebook). This study was carried out to investigate the cooling effect of separate type thermosyphon and to find the adequate parameters affecting the separate type thermosyphon. The heat transfer characteristics of separate type thermosyphon were obtained from experimental results. A $50{\times}50{\times}2 mm$ heat source was copied after CPU for the experiments. The results indicate that the device is capable of dissipating 60W of thermal energy and keeping the heat plate surface temperature under 50'E and the device can transfer heat from the evaporator to the condenser through natural circulation (without any external driving forces). Some transport phenomena of the working fluid and the heat transfer characteristics of the loop were observed in the experiments and are discussed in detail below.