• 제목/요약/키워드: Cooling ducts

검색결과 13건 처리시간 0.018초

CFD 시뮬레이션을 이용한 냉장컨테이너의 열유동 설계 (Design of Heat and Fluid Flow in Cold Container Using CFD Simulation)

  • 윤홍선;권진경;정훈;이현동;김영근
    • Journal of Biosystems Engineering
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    • 제33권6호
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    • pp.396-403
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    • 2008
  • Because thermal non-uniformity of transported agricultural products is mainly affected by cooling air flow pattern in the cold transport equipment, the analysis and control of flowfield is key to optimization of cold transport equipment. The objectives of this study were to estimate the effects of geometric and operating parameters of cold container on the air flow and heat transfer, and find the optimum design parameters for the low temperature level and its uniformity in given cold container with CFD simulations. Existences of ducts, gaps between pallets and geometries of exit as geometric parameters and fan blowing velocity as operating parameter were investigated. CFD simulations were carried out with the FLUENT 6.2 code. The result showed that optimum design condition was bulk loading with no duct, wall exit and 8.0 m/s of fan blowing velocity.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

생식소 동결에 의한 누에 유전자원의 장기보존 (Long-term Preservation of Bombyx mori Stocks by Frozen Gonad Storage)

  • 김삼은;성수일;이상몽
    • 한국잠사곤충학회지
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    • 제34권1호
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    • pp.1-7
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    • 1992
  • 생식소동결로 누에 유전자원을 장기보존하기 위하여 생식소의 생식방법, 최적 동결속도 및 동해방지제, 동결매액의 과냉거점과 빙점, 생식소 동결시기 등, 생식소의 동결보존에 필요한 기초자료를 검토하여 다음의 결과를 얻었다. 1. 생식소 피다식 누에의 마취에 적합한 방법은 에칠에텔, 냉수침지, 저온접촉, 탄산가스 접촉 중 냉수에 10분간 침지처리하는 것이었다. 2. 누에난소를 동결함에 있어 그리세롤과 DMSO는 우수한 동결방지 효과를 보였으나 솔비톨은 부적합하였다. 3. 9-15%의 그리세롤을 첨가한 동결매액의 과냉거점과 빙점을 조사하여 잠열발생량을 2.0-4.5$^{\circ}C$로 억제할 수 있는 동결속도를 확인하였다. 4. 5령보다 4령누에에 난소를 이식하는 것이 난소생존 및 완성난형성 면에서 1.3-1.4배 유리하였다. 5. 동결난소를 이식받은 암나방을 수나방과 교미시켜 수정란을 얻었으며, 유전형질검정으로 이 수정난에서 발생한 차세대 누에가 동결난소에서 유래한 것임을 확인하였다. 6. 4령 또는 5령기에 동겨정소를 이식한 수나방과 교미한 정상 암나방 중 수정난을 산란한 것은 없었다.

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