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태양열입사량, 환기량 및 종횡비의 변화에 따른 환기식 3중 집열창시스템의 열전달특성
김무현,정의준,오창용 울산대학교 1998 공학연구논문집 Vol.29 No.2
동절기 실내 난방시 별도의 환기열손실을 고려할 필요가 없는 환기식 3중 집열창에 대하여 열전달특성을 수치해석적으로 연구하였다. 주요변수로 환기량을 나타내는 Re수, 종횡비 그리고 태양열입사량등을 고려하였다. 연구결과 외기열손실을 최소화하기 위해서는 종횡비가 낮을수록 더 많은 환기량이 요구되었다. 밀폐식3중창과 비교하여 볼 때 환기식3중창은 입사량 10W/m², 종횡비 0.05, Re수 600인 경우 약 85%까지 외기열손실이 감소되는 것으로 나타났으며 태양열입사량이 작을수록 외기열손실 감소효과가 커진다는 결과를 얻었다. 또한 환기식 집열창의 설계시 종횡비는 0.05내외가 적절하며 환기량[Re수]은 600 이내의 값을 택하는 것이 바람직한 것으로 나타났다. The heat transfer characteristics of a triple glazed airflow window system is studied numerically by a finite volume method. Attention is paid to the effects of solar energy power, ventilation rate and window geometry on the flow field and thermal performance. As a result of the comparison between airflow window and enclosed window, the ambient heat loss of airflow window is reduced remarkably. It is suggested that in the design of airflow window system aspect ratio, H/W≒0.05 and Re ≤600 are appropriate.
播種基差異가 무우 品種의 生胎反應 및 種子 生産에 미치는 影響
金翰琳,吳昌容 濟州大學校 亞熱帶農業硏究所 1992 亞熱帶農業硏究 Vol.9 No.-
무(Raphanus sativus L.)의 播種期에 따른 品種의 生態反應과 種子生産에 미치는 영향을 밝히기 위하여, 하루방월동무우, 서울대형 봄무우, 영광무우, 신영광무우를 11月 20日부터 15日 간격으로 10回 播種하고 이들에 대한 實用形質을 조사하여 얻은 결과는 다음과 같다. 1.描苔 및 開花日數는 早播할수록 길어지고 晩播할수록 짧아졌다. 각 파종기에서 서울대형봄무우가 가장 日數가 길고, 하루방월동 무우가 중간이며, 영과무우와 신영광무우는 짧았다. 2. 草長은 각 파종기에서 하루방월동무우가 가장길고, 영광무우와 신영광무우는 짧았으며, 分枝數도 파종기가 늦어짐에 따라 감소되고, 품종별로는 하루방월동무우가 많았으나, 그외의 품종은 차이가 없었다. 3. 穗長의 길이는 파종기간에 차이가 없었으나 品種間에는 차이가 뚜렷하였다. 4. 穗當莢數는 하루방월동무우와 서울대형봄무가 많고, 莢當種實數은 서울대형봄무우가 가장 많았으며, 晩播할수록 其 數가 적었고, 百粒重도 晩播할수록 가벼웠다. 5. 區當種實重은 하루방월동무우가 가장 무겁고, 다른 품종들간에는 차이가 없었으나, 파종기가 늦어짐에 따라 모든 품종의 종실수량이 감소되었다. 6. 根重는 파종기가 늦어짐에 따라 증가되었으며, 특히 서울대형봄무우는 3月 5日이후의 파종에서 根重이 급속히 증가하였다. 7. 무의 採重量은 4개 품종 모두가 描苔 및 開花日數와 正의 상관관계가 있어서, 描苔 및 開花日數가 길수록 종자 생산량도 많았다. Influence of Seeding Dates on Ecological Response and Seed Production in Radish Cultivars This investigation was conducted to determine the influence of seeding dates on ecological response and seed production in radish. Cultivars varying in ecotype or Harubang, Seouldaehyung, Yeongkwang and Shinyeongkwang were seeded ten times at intervals of 15days from November 20. The results obtained were summarized as follows: 1. Days to bolting and days to flowering were prolonged in early seeding and shortend in late seeding. The days were long in Daehyung. medeum in Harubang and short in Yeongkwang and Shinyeongkwang. 2. Plant height was greater in Harubang than in the others on every seeding date. The number of branches was reduced as the seeds were sowed late and that of Harubang was large but there were not different between the other cultivars. 3. Inflorescence length had no difference between seeding dates, having significant differences between the cultivars. 4. The number of pods per inflorescence was large in Harubang and Seouldaehyung. The number of seeds per pod was greatest in Daehyung and late seeding reduced the number. One hundred seed weight was light in lated seeding. 5. Seed yield per plot was high in Harubang and there were not significant differences between the other cultivars. As the seeding was late, the yield was reduced. 6. Root weight was increased as seeding date was late. The weight in Daehyung was increased rapidly after seeding on March 5. 7. Seed yield in the four cultivars tested had positive correlations with days to bolting and days to flowering, that is, the longer days to bolting and flowering were, the higher the seed yield was.
오창용(Chang-yong Oh),유승우(Seung-Woo Yoo),임홍섭(Hong-seop Im) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
It is important for steel industries to reduce fuel consumption and pollutant emissions simultaneously. In this study, oxygen-air premixed combustion technology was experimentally studied to investigate its effects on flame temperature and NOX concentration using 2 staged burner. And applying method for a furnace in operation is also considered numerically. From the results, using 2 staged combustion enables both increasing flame temperature and controling the formation of NOX. And a oxygen injection nozzle design for homogeneous mixing between combustion air and oxygen is supposed for the technology application in a reheating furnace.
터보팬 엔진의 축류압축기 서지가 엔진성능에 미치는 영향
오창용(Chang-Yong Oh),구자예(Ja-Ye Koo) 한국추진공학회 2009 한국추진공학회지 Vol.13 No.3
This thesis has analyzed the effect of the surge happening in flight on the engine performance, especially on the PW4000 turbofan engine. It is to be judged that the flight surge can occur more often at the time of takeoff than it does en route due to the fact that the engine parameters are prone to fluctuate. EPR is judged to be the most highly sensitive parameter responding when surge occurs. Both Engine rpm and Wf decrease almost simultaneously just like an EPR. During the take-off rolling, N1 vibration is more sensitive than the N2 vibration. Consequently, the surge can be detected by EGT increase, while the other parameters (EPR, rpm, Wf, etc) decrease.
산업용 버너에서의 LNG, LPG/Air 연소특성 비교연구
오창용(Changyong OH),성연모(Yonmo SUNG),김승태(Seungtae KIM),유승우 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
The influence of gaseous fuel type and load on flame characteristics was experimentally investigated in a 1.3 MWth reheating furnace burner. In this study, LNG, LPG, and LPG/Air were selected as fuel, and fuel loads were set to 15%, 30%, and 60% in order to study gas interchangeability. The experimental results showed that the fuel change shows minor effect on the flame appearance for different fuel load conditions. The flame straightness performance was degraded under 30% fuel load conditions. The flame straightness performance was improved by injection of the burner center air. Minimum 10% air was required to improve the flame straightness performance compared to without burner center air conditions.
터보팬 엔진의 축류압축기 서지가 엔진성능에 미치는 영향
오창용(Chang-Yong Oh),구자예(Ja-Ye Koo) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.5
본 연구에서는 PW4000 엔진의 축류압축기 서지 발생이 엔진성능에 미치는 영향에 대하여 연구하였다. EPR은 서지 발생과 동시에 급격히 저하하는 것으로 나타나 민감도가 가장 큰 파라미터였다. N1 rpm과 N2 rpm도 EPR과 거의 동일한 경향으로 감소하였으며, Vibration 변화는 크지 않았으나 N1 Vibration 변화가 상대적으로 크게 나타났다. 따라서 비행중 EPR, N1 rpm, Wf 값이 급격히 저하되고 EGT가 비선형적으로 상승하는 상태로서 서지 발생을 감지할 수 있을 것으로 판단된다. This thesis has analyzed the effect of the surge happening in flight on the engine performance of the PW4000 turbofan engine. EPR is judged to be the most highly sensitive parameter responding when surge occurs. Both N1 rpm and N2 rpm decreases almost simultaneously just like an EPR. During the take-off rolling, the N1 vibration is more sensitive than the N2 vibration. Consequently, the surge can be detected by EGT increase, while the other parameters decrease.