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조핵제로서 실리카 입자가 물의 과냉각 해소에 미치는 영향
강채동,이동규 대한설비공학회 2024 설비공학 논문집 Vol.36 No.4
조핵제로서 실리카 입자를 함유한 증류수에 대한 냉각 실험을 수행하였으며 과냉각 현상을 관찰하였다. 본 연구의 결과를 요약하면 다음과 같다. 1) 냉각온도가 낮은 -30℃에서 과냉도와 냉각률이 반비례하였으며 조핵제가 혼합되지 않은 증류수보다 작은 과냉도를 나타내었다. 2) 냉각온도가 높아질수록, 즉 -20, -10℃일 때 조핵제 종류와 관계없이 과냉도 해소시간은 점점 길게 나타나는 경향을 보였다3) 실리카 입자 조핵제 GB3를 가진 증류수에서 제일 큰 평균 과냉도(11.3 K)를 보였다. 4) 조핵제로 사용된 입자들의 평균 지름 또는 단위질량 당 비 표면적은 카올린이 가장 크고, 실리카 입자 GB1에서 GB4 순으로 나타났다. 5) 평균 입자 지름이 클수록 해소 없이 과냉각 상태를 유지하는 개체수가 증가하였다. 6) 조핵제 가운데 카올린 입자 함유 시료에서 평균 과냉도가 6 K으로 가장 작게 나타났으며 실리카 입자 가운데에서는 GB1에서 과냉도(2.47 K) 및 평균 과냉도(약 9 K)가 최소로 나타났다. 이상의 본 연구의 실험 결과 분석을 통하여 미세 실리카 입자를 물 또는 증류수의 조핵제로 사용하기 위해서는 입자가 보다 균일하고 미세한 구조를 갖는 것이 유리함을 확인하였다. In this study, effects of silica fine particles as nucleates on supercooling that occurs during water cooling as a way to efficiently produce ice used as a high-lighted cold storage material were determined. To enhance freezing of supercooled water, silica particles with different sizes ranging from tens to hundreds of microns were added to distilled water. Cooling experiments were then performed for more than 10 cooling and recovering cycles. The cooling experiment showed that the supercooling degree tended to decrease as the size of the particle became smaller compared to the same mass of administered particles. Through the experiment, we obtained results on the possibility of using silica particles as nucleating agents to help release supercooling of water if particles could be made finer and more homogenized. In addition, basic data obtained from this study could change the existing perception of the uniqueness of nucleating agents as materials.
강채동 대한설비공학회 2001 설비저널 Vol.30 No.6
아이스슬러리형 빙축열을 위한 축열재료를 소개하고 시스템에 도입하기 위한 축열재료의 연구 및 개발성과를 개괄적으로 소개하기로 한다.
강채동,강용태,홍희기 대한설비공학회 2002 설비공학 논문집 Vol.14 No.12
To resist ice adhesion on cooling wall is concerned to continuous ice formation in thermal storage system. In this study, ice slurries were formed with two ecological aqueous solution, one is ethanol+silanol and the other is propylene glycol+silanol. By freezing under stirring the solution of $300m\ell$ in a stainless steel vessel which was immersed and cooled in a temperature controlled bath, the shape of ice slurry and the strength of ice adhesion on wall was observed with measuring the temperature and stirring load variation. As the concentration is smaller and the supercooling degree is larger, the ice adhesion is easy to occur. When the stirring load is larger than$ 2.1\times10^{-5}W$, the ice adhesion occurred.
강채동,손권,백종현,홍희기,Kang, Chae-Dong,Son, Kwon,Baek, Jong-Hyun,Hong, Hee-Ki 대한설비공학회 2002 설비공학 논문집 Vol.14 No.12
Ice adhesion on cooling wall is very important in continuous ice formation. The purpose of the present study is to investigate the possibilities of a three-component aqueous solution as a thermal storage material for the continuous ice formation. By freezing under stirring the solution of 300 mL in a stainless steel vessel which was immersed and cooled in a temperature controlled bath, an ice slurry was formed experimentally with measuring the temperature and stirring load variation. From the experiment, the ice adhesion was suppressed when the supercooling degree decreased and the concentration of aqueous solution increased.
The Effect of Solution Pressure to the Release in a Supercooled Aqueous Solution
강채동,김병선,홍희기 대한설비공학회 2009 International Journal Of Air-Conditioning and Refr Vol.17 No.1
Supercooled type ice storage system with aqueous solution (or water) may have trouble with non-uniform release of supercooling even though it contributes to the simplicity of system and ecological improvement. The non-uniform release increases the instability of the system because it may cause an ice blockage in pipe or cooling part. In order to suppress the release of the supercooling, a cooling experiment was tried to an ethylene glycol(EG) 3 mass% solution corresponding with pressurization. Also, the frequency ratio of the release of the supercooling was measured to the pressurization from 101 to 505 kPa. At results, the frequency ratio of supercooling release tends to decrease as the pressure of the aqueous solution increased in each cooling rate. Moreover, it tends to decrease as the cooling rate of the solution decreased in each pressure.
강채동,신계수 한국전기전자재료학회 2010 Transactions on Electrical and Electronic Material Vol.11 No.4
An automotive IC voltage regulator which consists of one-chip based on a metal-oxide semiconductor field effect transistor (MOSFET) is investigated experimentally with three types of packaging. The closed type is filled with thermal silicone gel and covered with a plastic lid on the MOSFET. The half-closed type is covered with a plastic case but without thermal silicone gel on the MOSFET. Opened type is no lid without thermal silicone gel. In order to simulate the high temperature condition in engine bay, the operating circuit of the MOSFET is constructed and the surrounding temperature is maintained at 100ºC. In the overshoot the maximum was mainly found at the halfclosed packaging and the magnitude is dependent on the packaging type and the surrounding temperature. Also the impressed current decreased exponentially during the MOSFET operation.