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실험계획법을 이용한 날개 없는 선풍기의 노즐 형상 최적 설계
정시영,이종수,윤재현,Jeong, Siyoung,Lee, Jongsoo,Yoon, Jaehyun 대한기계학회 2017 大韓機械學會論文集A Vol.24 No.2
날개 없는 선풍기는 특유의 형태로 인한 안전성과 청소의 간편함, 심미성으로 제품화에 성공하였다. 그러나 기존 선풍기에 비해 약한 바람과 모터에 의한 소음과 같은 단점은 구매력을 감소시키는 주요인이며, 따라서 모터의 속도를 증가시키지 않고 바람의 세기를 증가시키는 방안이 필요하다. 본 연구에서는 질량유량에 영향을 주는 인자, 수준을 선정하고 이를 실험계획법인 직교배열표를 이용하여 실험점을 배치하였다. 질량유량의 값은 전산유체해석 프로그램인 ANSYS FLUENT를 사용하여 질량유량의 값을 확인하였으며, 평균분석을 통해 질량유량에 가장 큰 영향을 주는 인자는 노즐 간격임을 확인할 수 있었다. 또한 예측 모델 식을 통해 얻은 질량유량의 값과 전산유체해석의 질량유량의 값이 가장 큰 값으로 일치하는 것을 나타내었다. 본 연구를 통해서 모터의 속도를 증가시키지 않더라도 형상 변화를 통해 질량유량의 증가시킴을 확인할 수 있었다. Bladeless fan is becoming increasingly popular owing to its advantages, such as improved safety, easy to clean, and attractive shape. However, many people are reluctant to purchase it because of several disadvantages, such as noise and moderate wind; therefore, research on how improve wind generation without increasing the motor speed is required. This study investigates the optimization of the shape of the nozzle and nearby surface using CFD (Computational Fluid Dynamics) simulation, ANSYS fluent. The results are analyzed by ANOM (analysis of mean) and interaction analysis; therefore this study suggests the variables of affecting Coanda effect and satisfy the govern equation, the conservation of momentum. The optimal combination was found through a predictive equation. In this study, factors and levels that affect the mass flow rate were selected and experimental points were arranged using the orthogonal array table. The value of the mass flow rate was confirmed by ANSYS fluent, which is a CFD program. Through the ANOM, it was confirmed that the nozzle distance is the most influential parameter affecting the mass flow rate. Furthermore, the mass flow rate obtained from the predictive equation and the mass flow rate from the CFD correspond to the largest values. Results from this study confirmed that the mass flow rate is increased by a change in the shape, even if the motor speed did not increase.
실험계획법을 이용한 날개 없는 선풍기의 노즐 형상 최적 설계
정시영(Jeong Siyoung),이종수(Lee Jongsoo),윤재현(Yoon Jaehyun) 대한기계학회 2017 大韓機械學會論文集A Vol.41 No.8
날개 없는 선풍기는 특유의 형태로 인한 안전성과 청소의 간편함, 심미성으로 제품화에 성공하였다. 그러나 기존 선풍기에 비해 약한 바람과 모터에 의한 소음과 같은 단점은 구매력을 감소시키는 주요인이며, 따라서 모터의 속도를 증가시키지 않고 바람의 세기를 증가시키는 방안이 필요하다. 본 연구에서는 질량유량에 영향을 주는 인자, 수준을 선정하고 이를 실험계획법인 직교배열표를 이용하여 실험점을 배치하였다. 질량유량의 값은 전산유체해석 프로그램인 ANSYS FLUENT를 사용하여 질량유량의 값을 확인하였으며, 평균분석을 통해 질량유량에 가장 큰 영향을 주는 인자는 노즐 간격임을 확인할 수 있었다. 또한 예측 모델 식을 통해 얻은 질량유량의 값과 전산유체해석의 질량유량의 값이 가장 큰 값으로 일치하는 것을 나타내었다. 본 연구를 통해서 모터의 속도를 증가시키지 않더라도 형상 변화를 통해 질량유량의 증가시킴을 확인할 수 있었다. Bladeless fan is becoming increasingly popular owing to its advantages, such as improved safety, easy to clean, and attractive shape. However, many people are reluctant to purchase it because of several disadvantages, such as noise and moderate wind; therefore, research on how improve wind generation without increasing the motor speed is required. This study investigates the optimization of the shape of the nozzle and nearby surface using CFD (Computational Fluid Dynamics) simulation, ANSYS fluent. The results are analyzed by ANOM (analysis of mean) and interaction analysis; therefore this study suggests the variables of affecting Coanda effect and satisfy the govern equation, the conservation of momentum. The optimal combination was found through a predictive equation. In this study, factors and levels that affect the mass flow rate were selected and experimental points were arranged using the orthogonal array table. The value of the mass flow rate was confirmed by ANSYS fluent, which is a CFD program. Through the ANOM, it was confirmed that the nozzle distance is the most influential parameter affecting the mass flow rate. Furthermore, the mass flow rate obtained from the predictive equation and the mass flow rate from the CFD correspond to the largest values. Results from this study confirmed that the mass flow rate is increased by a change in the shape, even if the motor speed did not increase.
정시영(Siyoung Jeong),윤한구(Han-Gu Yun),박기웅(Kiwoong Park),박성룡(Seong-Ryong Park),김민성(Minsung Kim) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
Hybrid heat pumps, which combine the vapor compression and absorption heat pump cycle, can efficiently produce hot water of 80~90℃ from the low temperature around 50℃. In this study, the performance of a two-stage hybrid heat pump(HHP) is compared with a single-stage hybrid heat pump using EES(Engineering Equation Solver). At the same operating condition, the two-stage HHP showed a bit high COP and more stable operating condition than single-stage HHP. Moreover, the maximum temperature of the two-stage HHP is decreased 40℃ that of the single-stage HHP. The COPs of both systems are decreased with the increase of UA-values. However the heat output of the HHP is increased as the UA-values are increased.
정시영(Siyoung Jeong),김민수(Min Soo Kim) 대한설비공학회 2013 대한설비공학회 학술발표대회논문집 Vol.2013 No.6
Natural gas plays a great role in the national energy economy. and the efficiency improvement of gas devices is becoming more and more important. In this study, the necessity and effect of supplying high-efficiency natural gas devices were investigated for CNG buses, gas boiler, and gas cooling. Considering energy consumption and environment, the necessity of improving the efficiency of these three devices was found to be very great for rational use of energy.
정시영(Siyoung Jeong),김대환(Dae-hwan Kim),박기웅(Kiwoong Park) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
To reduce the peak demand the promotion of gas cooling(absorption chillers and GHPs) is required. In this study the effect of electric power peak-cut has been analyzed using two methods. One is based on monthly LNG consumption data and the other is using the gas cooling capacity installed. Both methods agreed well with each other within the uncertainty of 20%. It was found that the gas cooling had the peak cut effect of 1,500 -2,000 ㎿ for recent 5 years (2003 - 2007). The ratio of gas cooling to the whole cooling demand was 12- 15%, which is needed to be increased.
정시영(Siyoung Jeong) 대한설비공학회 2012 대한설비공학회 학술발표대회논문집 Vol.2012 No.6
In this study, the merits of partnership contract policy is discussed. and various measures to boost the partnership contract policy are suggested. It is required to enlarge the limits of the present regulation. Moreover, the partnership contract policy should be developed into the separate contract policy in order to increase the mutual interest of various participants of the construction industry.
다채널 미세관에서 이산화탄소의 충전량이 증발열전달에 미치는 영향
정시영(Siyoung Jeong),박동호(Dongho Park),김대환(Dae-hwan Kim),민병준(Byung-Jun Min) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
One of the most important factors in applying miniature tube to carbon dioxide refrigeration system is refrigerant distribution. In this paper, evaporating heat transfer characteristics were experimentally investigated relating the charge of carbon dioxide in a multi-channel miniature channel. The heat transfer coefficient of the 6-channel aluminum tube was measured at various charges. It was found that the dryout quality and heat transfer coefficient were heavily dependent on the maldistribution of carbon dioxide. If the charge of CO₂ was not enough, maldistribution in the multi-channel miniature tube became serious and a sudden drop of heat transfer coefficient was observed. These phenomena were conspicuous at high mass flux of CO₂.