• 한국해양학회지
• /
• v.17 no.2
• /
• pp.51-58
• /
• 1982

Density inversions are investigated by using the oceanographic data of temperature and salinity obtained in the Japan Sea Srom 1965 To 1979. The density inversions are found more frequently in winter than summer. About one half of the Japan Sea has the density inversions in winter, while in summer, they appear only in the small part os the Korean Strait. The inversions are usually sormed surface layers of a few tens of meters. Such phenomena can be explained by the advection of cold water in the suface layer by Ekman drift: In winter, the southward flow of surface cold water due to northwesterly monsoon causes the density inversions, and in summer, surface layer on the Korean strit unstable.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.10 no.1 s.20
• /
• pp.55-59
• /
• 2004

Temperature inversion off Wasaka Bay in the East Sea was studied using data measured on a CREAMS cruise in June of 1995 and 1996. Temperature inversion occurred mainly at the upper layer of the thermocline at a depth of no more than 20 m and around the thermal front between the TWC and the coastal waters of Japan. At some stations. temperature inversion had an influence un density inversion, while, in some other stations, high salinity water prevented density inversion.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2011.06a
• /
• pp.323-323
• /
• 2011

본 연구는 냉각점이 중간에 위치하는 정적제빙형인 관외 제빙기내에서의 물의 자연대류 현상에 대해 수치적으로 다루고 있다. 자연대류현상과 열전도에 의해 조절되는 물에 이동을 유한차분법을 이용해 2차원적으로 계산하였다. 또한, 본 연구에서는 물의 온도가 4[$^{\circ}C$]에서 밀도역전현상이 일어나는 것을 수치해석의 결과와 비교한다. 자연대류의 변화에 따른 결과는 수치해석을 통해 등온선과 유선형의 그래프로부터 알 수 있었다. 그 중에서도 물의 온도와 밀도의 관계에 따라 자연대류의 변화가 일어나는 것을 수치해석을 통해 알 수 있었다.

• 한국해양학회지
• /
• v.18 no.1
• /
• pp.43-48
• /
• 1983

Oceanic temperature inversions, with unstable stratifications, are frequently founed in the surface layer of a few tens meters in the Japan Sea and the Yellow Sea in Winter. Mechanisms responsible for the generation of temperature inversions include the followings: (1) The nat heat loss at the sea suface requires an upward transport of heat from the interior of the ocean y convection, and this convection leads to the temperature inversions. (2) The downward propagation of the annual variation of the sea surface timperature, with an exponential decrease of amplitude and a linear change of phase with depth, generates the surface inversion layer in winter. (3) The cold water cdvection by Ekman drift, of which magnitude decreases exponentially with depth, generates temperature inversions for the three possible mechanisms mentioned above.

• Water for future
• /
• v.23 no.4
• /
• pp.459-466
• /
• 1990

In the Ice Valley, it freeze in summer season. However, there is no ice during winter. In order to clarify the phenomenon of unusual temperature, numerical experiments were conducted using the coupled equations of fluid flow and heat transfer. The results demonstrated that temperature inversion in the Ice Valley is primarily due to delay of the groundwater temperature. Also, the results of the simulation suggest that major factors affecting the delay are the topographical configuration, geological factors and groundwater flow system, combined with groundwater recharge and discharge systems.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.18 no.2
• /
• pp.91-96
• /
• 1982

Temperature inversions are investigated by using the oceanographic data obtained in the Yellow Sea from 1965 to 1979. The temperature inversions are found in every depth in almost all areas of the Yellow Sea. While in summer, they frequently occur below thermocline in the west region of the Jeju Island. Such phenomena in winter can be explained by surface cooling effects associated with a net heat loss at the surface and a southward advection of cold water, and those in summer result from the process of mixing between the Yellow Sea Warm Current and the Yellow Sea Bottom Cold Water.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.8 no.5
• /
• pp.498-504
• /
• 1984

가열된 곡면에 의한 자연대류에서는 유동의 박리현상이 존재하지 않음이 알려져 있다. 이에 반해 날카로운 모서리를 갖는 가열된 정방형 수평실린더에 의한 자연대류에서는 그라소프 수가 4.66*$10^{4}$ 전후로 부착 혹은 박리현상이 윗쪽 양 모서리 부근에서 일어남을 광학간섭 계(Mach Zehnder Inter-ferometer)를 이용하여 온도장을 가시화하고 이를 이용하여 좌우 대칭 선상에서의 속도분포를 간단한 대수적인 방법으로 구하여 수평정방형 윗쪽 수평면 위에 유동의 박리현상을 시사하는 "쌍동이 소용돌이"의 존재를 입증하였고, 이에 의해 온도역전현상과 평균 열전달량의 급격한 증가를 설명 할 수 있다.설명 할 수 있다.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 1999.10a
• /
• pp.242-243
• /
• 1999

전기집진기는 산업 분진 및 폐가스 집진을 위해 널리 이용되며, 고전기 저항 분진에 의한 집진극 표면의 역전리가 전기집진기에서 가장 큰 문제이다. 이런 역전리 현상을 방지하기 위해 가스온도 제어, 가스조건, 하전 제어 등 다양한 방법이 시도되고 있다. 전기집진기에서 고 비저항 분진 및 역전리의 영향으로부터 높은 집진효율을 얻기 위한 방법 중 하나로 이동 전극형 방식(Moving Electrode Electrostatic precipitator, MEEP)과 고정전극형 (Fixed Electrode Electrostatic precipitatior, FEEP)에 펄스하전 방식으로 구성된 조합형 전기집진기가 개발되고 있다.(Toshiaki Misaka etc. 1996)(중략)

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.27 no.4
• /
• pp.213-219
• /
• 2015

A thermal storage tank with internal heat exchange coils is commonly used in solar thermal systems with a collector area below $100m^2$. The coils are installed in the lower part of the tank because the temperature of the upper part of the tank can drop if the outlet temperature of the collector becomes lower than the upper temperature of the tank, which is a kind of temperature reversal. As an alternative to the well-mixed storage tank with lower coil only, we have proposed a tank with lower and upper coils and have achieved superior thermal stratification in the tank, which results in increased collector efficiency and solar fraction. But, the phenomenon of temperature reversal was often observed in the tank when the load or solar radiation changed rapidly. In the present work, revised control was successfully applied, i.e., to heat only the lower coil using a three way valve if temperature reversal occurs and to operate the collector at a low flow rate when the quality of solar radiation is not good.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.6
• /
• pp.1337-1342
• /
• 2007

An experimental study has been performed to investigate the performance and heat transfer characteristics of the heat exchanger for simultaneous cooling/heating heat pump. The heat transfer performance was measured using an air-enthalpy calorimeter and a constant temperature water bath, to obtain the performance evaluation and analysis of a fined tube heat exchanger. Six finned tube heat exchangers with louver fin were tested under a heating condition. Air-side heat transfer and friction were presented in terms of j-factor and f-factor. The heat transfer coefficient increased with decreasing the fin pitch, j-factor and f-factor on the fin pitch and the number of tube rows decreased with increasing Reair.