• 한국시뮬레이션학회논문지
• /
• 제28권1호
• /
• pp.49-56
• /
• 2019

전산해석과 풍동시험을 이용하여 유도형 활공탄약의 공력특성을 연구하였다. 전산해석으로는 반실험적 기법인 Missile DATCOM과 전산유체역학 해석프로그램인 FLUENT를 사용하였다. 유도형 활공탄약에 대해 양력 및 항력, 피칭모멘트 등을 계산하여 기본적인 공력특성을 확인하였으며 기존의 탄약과는 전혀 다른 공력특성을 갖는 것을 확인했다. 전산해석을 통해 얻은 결과는 풍동시험을 통해 얻은 결과와 대체적으로 유사했다. 반실험적 기법으로 얻은 결과 중 피칭모멘트 값은 풍동시험결과와 약간 차이가 났지만, 전체적으로 전산해석의 결과는 시험결과와 유사한 경향과 값을 나타냈다. 본 연구를 통해 유도형 활공탄약의 공력특성을 확인하였으며, 유도형 활공탄약 초기설계 시 공력특성 분석을 위해 반실험적기법 및 전산유체역학적 해석 기법을 적용할 수 있음을 확인하였다.

• 한국유체기계학회 논문집
• /
• 제11권5호
• /
• pp.44-49
• /
• 2008

As the alternative energy, renewable energy should have been developing by many techniques, in order to substitute the fossil fuel which will be disappeared in the near future. One of the small hydropower generator, main concept of tubular turbine is based on using the different water pressure levels in pipe lines, energy which was initially wasted by using a reducing valve at the end of the pipeline, is collected by turbine in the hydro power generator. A propeller shaped hydro turbine has been used in order to use this renewable pressure energy in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the guide vane opening angle are examined in detail. First, it ensures the reliance of CFD by that of compared with experiment data. After all, the results of performance characteristics of the CFD and experiment show to confirm the data that power, head and efficiency of less than 4%, 2% and 5% respectively. Moreover influences of pressure, tangential and axial velocity distributions on turbine performance are investigated.

• 한국분무공학회지
• /
• 제20권2호
• /
• pp.70-75
• /
• 2015

Swirl flow in the gun type burner has an impact on the stabilization of the flame, improvement of the combustion efficiency. The swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed electronic spark plug, injection nozzle, combustion device adaptor, and spinner. These inner components change the air flow behavior passing through airtube. So, this study conducted the measurement using by hot-wire anemometer and analyzed effect of the swirl number of spinner on the exhaust air of gun type burner. Turbulence characteristics come up in this study was mean velocity, turbulence intensity, kinetic energy, shear stress and flattness factor of the air flow with the change of the distance of axial direction and tangential direction from the exit of the airtube.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.897-902
• /
• 2007

The turnover-type sluice gate is typically actuated by the open circuit hydrauic system since the single-rod cylinder is used rather than the double-rod cylinder. However, here the closed circuit hydrauic system is applied for the operation of turnover-type sluice gate for the purpose of convenient operation. The closed circuit hydraulic system of turnover-type sluice gate is composed of a bi-directional pump, single-rod cylinders, pilot operated check valves, check valves and a counter balance valve. The usefulness of the closed circuit hydraulic system is verified for the several operational conditions by the computer simulations.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.1117-1119
• /
• 2001

This paper describes the forward type pulse power supply using a Power-MOSFET in the view of commercialization. The principle of basic operating and the operating characteristics of the forward type pulse power supply are estimated by the switching frequency, coupling factor and duty ratio. It is shown that theoretical and experimental results are in good agreement by comparing simulation and experimental results when a lamp type ozonizer can be used as a load. Also, experimental results indicate that the discharge and ozone concentration characteristics of the manufactured pulse power supply is more improved compare to the conventional pulse power supply[5]. This proposed supply show that it can be practically used as a pulse power supply in various environment improvement facilities.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제50권12호
• /
• pp.614-621
• /
• 2001

In this Paper, the ozonizer is fabricated by piling plate-type electrodes up to minimize and reduce install space. Hereby ozone generation characteristics of piled plate-type ozonizer were investigated. Inverse-polarity voltage was generated by H.V neon transformer. And 2 H.V neon transformers were used to supply high voltage each 9 electrodes of plate-type ozonizer. According to the experiments, ozone concentration, generation and yield were proportionally increased tilth increasing the number of electrode. And the maximum increase effects of 246%, 245%, and 33% were obtained when the number of electrode were increased from 3 up to 9.

• 한국실내디자인학회논문집
• /
• 제22호
• /
• pp.16-22
• /
• 2000

The purpose of this study is to analyze characteristics of set-booth in beauty salon as well as to suggest the basic design data for franchise beauty salon. The method of this research was based on field observation of the franchise beauty salon in Seoul. The results of this research are as follows. 1) In set-booth type analysis, set-mirror wall type and set-mirror partition type are mainly used, but set-mirror table type is not showed in this research. 2) In terms of scale, wall type and partition type are classified as large scale, wall type and partition type are used as meduim scale. In shop front analysis, the result is shown in two things. If it is type, they used partition type and if it is close type, they used wall type. 3) Set-mirror is consisted of mirror and drawer and it is classified by 4 types with combination method. In a result, most of them used separated mirror type because they want to emphasize the separation between set booth and its layout. 4) Lighting method has 4 types; corniced type, bracket type, pendant type and downlight type. Among them, downlight is showed as the most-used.

• 교육시설 논문지
• /
• 제24권5호
• /
• pp.3-10
• /
• 2017

This study was tried to find out characteristics of students' movement in classroom and homeroom. The object was the school whose homebase management was different by grade. Observation research was tried about middle school class that is simultaneously worked with different type of homeroom and the movement of students under various situations was analyzed. As a result, students in exclusive subject classroom moved in short time within one or two minutes after class. In case of exclusive homeroom, returning frequency of students was nearly about 85 to 100 percent within ten minutes in end of end. Behavioral characteristics of students in dual purpose homeroom was similar in exclusive subject classroom. The class using dual purpose homeroom showed high ratio in use of center homebase, therefore, returning frequency at short recess time was extremely low. In case of dual purpose homeroom at lunch time, next class students moved in early time and maximized within one or two minutes in end of end. These results are thought to be useful for planning spaces of variation type.

• 한국작물학회지
• /
• 제44권1호
• /
• pp.64-69
• /
• 1999

Gelatinization characteristics of 111 glutinous rice varieties were evaluated by Rapid Visco Analyzer. Gelatinization viscosity of glutinous rice tested varied with ecotypes or varietal groups: indica, japonica, and Tongil type. Indica rice showed the highest average value of initial pasting temperature. The average values for peak, hot, and cool viscosities were highest in Tongil-type rice, and lowest in japonica rice. Japonica showed the lowest breakdown and consistency, but the highest setback value. Indica was lower in alkali digestion value (ADV), and shorter in gel length after gelatinization thanjaponica and Tongil-type. Glutinous rices tested could be divided into six groups by cluster analysis based on their gelatinization characteristics. Group I-A was mostly early maturing japonica varieties while I-B was mostly indica and Tongil-type rices. Groups II-A and II-B were consisted of very early maturingjaponica, and III-A and III-B included medium or medium late maturingjaponica varieties. Group III-A showed the lowest average values of peak, hot, cool, and consistency viscosities, and also in breakdown and setback ratios. Group I-B revealed the highest values in peak, hot, cool, breakdown, and consistency viscosities. ADV was low in groups I-A, I-B, and II-B, and gel consistency was not different among the six varietal groups. Principal component analysis using seven traits related with gelatinization produced four effective components, and the first and second components were highly correlated with all the gelatinization characters evaluated.

• 한국재료학회지
• /
• 제21권10호
• /
• pp.532-541
• /
• 2011

The Xe plasma flat lamp, considered to be a new eco-friendly LCD backlight, requires a further improvement of its luminance and luminous efficiency. To improve the performance of this type of lamp, it is necessary to understand the effects of the discharge variables on the luminous characteristics of the lamp. In this study, the luminous characteristics of a coplanartype Xe plasma flat lamp with a teeth-type electrode pattern were analyzed while varying the gas composition, gas pressure and input voltage. The effects of the phosphor layer on the discharge and the luminous characteristics of the lamp were also studied. The luminous efficiency of the coplanar-type Xe plasma flat lamp improved as the Xe input ratio and gas pressure increased. Higher luminous efficiency was also obtained when helium (He) was used as a buffer gas and when a phosphor layer was fabricated on the electrode region. In contrast, the luminous efficiency was reduced with increasing the input voltage. It was found that the infrared emissions from the lamp were affected by the Xe excitation rate in the plasma, the Xe gas density, the collisional quenching of excited Xe species by gas molecules, and the recombination rate between the Xe ions and electrons.