• Title/Summary/Keyword: 급냉각

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초고온금형 시스템(E-Mold) 및 응용사례 소개

  • Kim, Gi-Yeong;Kim, Dong-Hak
    • Journal of the KSME
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    • v.51 no.4
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    • pp.45-49
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    • 2011
  • 이 글에서는 플라스틱 사출 성형에 있어 금형 표면온도와 응용 수지의 온도 차이로 필연적으로 발생되는 표면 결함, 미성형 등의 다양한 사출 성형 문제를 해결하기 위해 사출 사이클에 맞추어 금형 표면 온도의 급가열-급냉각을 제어할 수 있는 E-Mold 시스템에 대해 실제 양산 적용사례를 중심으로 소개하고자 한다.

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A Study on the Thermal Analysis of Spray Cooling for the Membrane Type LNGC During the Cool-Down Period (급냉각기간에서 멤브레인형 LNGC의 분무냉각 열해석에 관한 연구)

  • Lee, Jung-Hye;Kim, Kyung-Kue;Ro, Sung-Tack;Chung, Han-Shik;Kim, Seong-Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.1
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    • pp.125-134
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    • 2003
  • The present paper is concerned to the thermal analysis during the cool-down period of 138,000 m$^3$class GTT MARK-III membrane type LNG carrier servicing with LNG from the Middle East to Korea. It is the cool-down period that cools the insulation wall and the gas in LNG tank to avoid the thermal shock as the start of loading of -162$^{\circ}C$ LNG. For six hours of the standard cool-down period, the temperature of NG falls down from -4$0^{\circ}C$ to -13$0^{\circ}C$ and especially the mean temperature of the 1st barrier in the top side insulation wall falls down from -38.38$^{\circ}C$ to -122.42$^{\circ}C$ in case of IMO design condition. By the 3-D numerical calculation about the cargo tank and the cofferdam, the temperature variation in hulls and insulations is precisely predicted in this paper. And the mean temperature variation of gas is calculated as the function of the spraying rate by the heat balance model during the cool-down period.

Thermal Analysis Comparison of IMO with USCG Design Condition for the INGC During the Cool-down Period (급냉각기간에서 IMO설계조건과 USCG 설계조건에 대한 LMGC 화물탱크의 열해석 비교)

  • Lee, Jung-Hye
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.11
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    • pp.1390-1397
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    • 2004
  • This study is concerned with the thermal analysis during the cool-down period of 135,000㎥ class GT-96 membrane type LNG carrier under IMO and USCG design condition. During the cool-down period, the spraying rate for the NG cooling decreases as the temperature of NG falls down from -4$0^{\circ}C$ to -l3$0^{\circ}C$, and the spraying rate for the cooling of the insulation wall increases as the temperature gradient of the insulation wall is large. It was confirmed that there existed the largest temperature decrease at the first barrier and the first insulation, which are among the insulation wall, especially in the top side of the insulation wall under IMO and USCG design condition. Also, as the NG temperature distribution is fixed, the outer temperature condition under the design condition has influence on the temperature variation at the insulation. By the 3-D numerical calculation about the cargo tank and the cofferdam during the cool-down period, the temperature variation in hulls and insulations is precisely predicted under IMO and USCG design condition. From the comparison between two conditions; IMO design condition shows more severe temperature gradient than USCG design condition, therefore, it provides the conservative estimation of the BOG.

Effects of Surface Roughness on Contact Angle of Nanofluid Droplet (표면조도가 나노유체 액적의 접촉각에 미치는 영향)

  • Kim, Yeung Chan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.6
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    • pp.559-566
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    • 2013
  • The effects of solid surface roughness on the contact angle of a nanofluid droplet were experimentally investigated. The experiments were conducted using the solid surface of a 10 mm cubic copper block and the nanofluid of water mixed with CuO nanoparticles. The experimental results showed that the contact angles of nanofluid droplets were lower than those of water droplets and that the contact angle of the nanofluid droplet increased with the solid surface roughness. Furthermore, it was found that the contact angles of water droplets on the solid surface quenched by both water and the nanofluid were lower than those of water droplets on the pure solid surface. However, significant differences were not observed between the contact angles on the solid surfaces quenched by water and the nanofluid.

Thermal Analysis for the GT-96 Membrane Type LNGC during the Cool-down Period (GT-96 멤브레인형 LNGC의 급냉기간에서의 열해석)

  • Lee, Jung-Hye;Choi, Hyun-Kue;Choi, Soon-Ho;Oh, Cheol;Kim, Myoung-Hwan;Kim, Kyung-Kun
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1346-1351
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    • 2004
  • This study is concerned with the thermal analysis during the cool-down period of 135,000 $m^3$ class GT-96 membrane type LNG carrier under IMO design condition. The cool-down is performed to cool the insulation wall and the natural gas in cargo tank for six hours to avoid the thermal shock at the start of loading of $-163^{\circ}C$ LNG. During the cool-down period, the spraying rate for the NG cooling decreases as the temperature of NG falls clown from $-40^{\circ}C$ to $-130^{\circ}C$ and the spraying rate for the insulation wall cooling increases as the temperature gradient of the insulation wall is large. It was confirmed that there existed the largest temperature decrease at the 1 st barrier and 1st insulation, which are among the insulation wall, especially in the top side of the insulation wall. By the 3-D numerical calculation about the cargo tank and the cofferdam during the cool-down period, the temperature variation in hulls and insulations is precisely predicted.

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A Study on the Rapid Cooling Vacuum System for the Storage and Transportation of the Cold Agriculture and Livestock Products (농축산물의 저장 및 유통을 위한 감압증발 급냉각 시스템에 관한 연구)

  • 김성규;김원녕;김경석;최순열;전현필
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.1
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    • pp.26-36
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    • 1997
  • Recently, the new refrigerating system, using non - fluorinated hydrocarbon refrigerants has to be developed for the agricultural fields. One of that kinds of systems is the cooling system using the water vapor and vacuum, in which the water evaporate at the low temperature under vacuum and absorb the large amount of the latent heat. If vapor with large amount of latent heat is removed from the system, the system is cooled accordingly. The characteristics of cooling under the vacuum was observed and measured using experimental apparatus, which is consisted of vacuum chamber, the ejectors, the pumps and the measurement apparatus. As the results of experiments, we know that the evaporation in the vacuum occurs vigorously when the materials to be cooled has more amounts of heat before cooling, and by which effects the materials can be cooled. The cooling vacuum system is more efficient than other methods when the agricultural products is chilled or dried.

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Evaluation for Applicability as the Inorganic Binder with Rapid Setting Property for Construction Material of LFS Produced from Various Manufacturing Process (다양한 철강제조공정에서 부산되는 전기로 환원슬래그의 급경성 무기결합재로의 적용성 검토)

  • Kim, Jin-Man;Choi, Sun-Mi;Kim, Ji-Ho
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.2
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    • pp.70-77
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    • 2012
  • The Ladle Furnace Slag, about 20% of the electric arc furnace slag, has high content of free CaO and free MgO, which generates the expansion collapse by hydration reaction. Although many researchers have been endeavoring to recycle the EAF reducing slag in construction fields, there is not found the effective recycling method up to now. However, the LFS(Ladle Furnace Slag) contains mineral composition of the system of calcium aluminate with high-reactivity. Therefore, it is possible to developed the quick setting property and the high strength at the early age by the rapid cooling. This study aimed to check the reactive minerals and predict the reactivity with water on the LFS discharged from different steel product plants. The test results show that many types of LFS has hydration reactivity and can use in construction field as a inorganic binder with the rapid setting property.

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Fabrication of an Electrostrictive Fluorinated Terpolymer Sheet Applicable to Artificial Muscle Systems (인공 근육에 응용 가능한 전기변형 불화 고분자 박막의 제작)

  • Kim, Sung-Jin
    • Journal of the Korean Vacuum Society
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    • v.20 no.4
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    • pp.276-279
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    • 2011
  • Polymer electrostrictor materials can exhibit high electroactive strain and hold increasing promise for a variety of actuator applications. The size of available actuators has been limited, however, by the solution-based casting and annealing process generally required to prepare electrostrictor actuator materials. We report on a high throughput melt and stretch extrusion process capable of creating large sheets of an electrostructive terpolymer, poly (vinylidene fluoride-trifluoroethylene-1, 1-chlorofluoroethlene) while producing a suitable crystallinity and crystal phase for high strain electrostrictor performance such as artificial muscle systems.

암모니아 합성반응기의 다중성 및 최적화

  • 이성준;함재용;이현구
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.377-382
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    • 1989
  • 암모니아 합성을 위한 다단식급냉반응기를 대상으로 물질 및 에너지보존법칙을 적용하여 수식모델을 전개하였다. 실제 4단 반응기의 설계 및 운전자료를 기준으로 하여 정상상태의 다중성을 해석하고 각 촉매층의 체적비와 반응물의 공급유량비에 대한 최적화 연구를 수행한 결과 실제 조업조건하에서 3개의 서로 다른 정상상태가 존재하며 실제 설계 및 조업조건은 최적조건을 다소 완화한 조건에 상당한 것임을 확인하였다.

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열처리가 Zr-2.5Nb압력관 재료의 지체균열전파 특성에 미치는 영향

  • 김인섭;오제용;김영석;국일현
    • Proceedings of the Korean Nuclear Society Conference
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    • 1995.05a
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    • pp.765-770
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    • 1995
  • 지체균열전파(DHC)는 중수로 압력관의 수명에 근 영향을 미치는 중요한 현상 중의 하나이다. 본 연구에서는 열처리를 통하여 압력관 재료인 Zr-2,5Nb의 기계적 성질, 집합조직을 변화시켜 각 인자들이 DHC에 미치는 영향을 조사하였다. 그 결과 지체균열전파속도(DHCV)는 항복강도와 경도와 비례한다는 것과 유사한 미세구조와 집합조직을 갖는 Zr-2.5Nb의 경우 항복강도와 Puls의 모델을 이용하여 지체균열전파속도(DHCV)를 예측할 수 있었다. 그리고 secondary cracking이 annealing한 시편들에서는 관찰되었으나 $\beta$열처리 후 급냉한 시편에서는 관찰되지 않았다. 이것의 수소화물 형상의 차이에 의한 것으로 생각된다.

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