• Title/Summary/Keyword: 방열 설계

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Thermal Characteristics of Concrete Fabricated with Blast Furnace Slag Subjected to Thermal Cycling Condition (고로슬래그 혼입 콘크리트의 고온 조건에서의 열역학 성능)

  • Yang, In-Hwan;Park, Ji-Hun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.4
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    • pp.414-420
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    • 2017
  • The thermal characteristics of concrete fabricated with blast furnace slag were investigated in this paper. Test parameters included water-binder ratio and the content of furnace slag. Experimental program were performed to measure mechanical properties including compressive strength and split tensile strength under high-temperature thermal cycling, and to measure thermal properties including thermal conductivity and specific heat. Test results showed that the residual compressive strength of mixtures with blast furnace slag was greater than that of mixture without blast furnace slag. In addition, thermal conductivity of mixtures with blast furnace slag was greater than that of mixtures without blast furnace slag. It indicates that blast furnace slag was favorable for charging and discharging in thermal energy storage system. Test results of this study would be used to design concrete module system of thermal energy storage.

Design and Evaluation of Aluminum Casting Alloys for Thermal Managing Application (방열소재용 알루미늄 주조합금 설계 및 특성평가)

  • Shin, Je-Sik;Kim, Ki-Tae;Ko, Se-Hyun;An, Dong-Jin;Kim, Myung-Ho
    • Journal of Korea Foundry Society
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    • v.33 no.1
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    • pp.22-31
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    • 2013
  • In order to develop an aluminum alloy, that can combine high thermal conductivity and good castability and anodizability, aluminum alloys with low Si content, such as Al-(0.5~1.5)Mg-1Fe-0.5Si and Al-(1.0~1.5)Si-1Fe-1Zn, were designed. The developed aluminum alloys exhibited 170~190% thermal conductivity (160~180 W/mK), 60~85% fluidity, and equal or higher ultimate tensile strength compared with those of the ADC12 alloy. In each developed alloy system, the thermal conductivity decreased and the strength increased with the increment of Mg and Si, which are the significant alloying elements. The fluidity was in reverse proportion to the Mg content and in proportion to the Si content. The Al-(0.5~1.5)Mg-1Fe-0.5Si alloys exhibited better fluidity in thick-wall castings, while the Al-(1.0~1.5)Si-1Fe-1Zn alloys were better in thin-wall castability due to their lower surface energies. The fluidity behavior was complexly affected by the heat release for the solidification, viscosity, solidification range, and the type, quantity, and formation juncture of the main secondary phase.

Performance Improvement of Stratified Thermal Storage Tank Using Heat Insulator (단열층 사용을 통한 성층 축열조 성능개선)

  • Lim, Se Hwa;Lee, Tae Gyu;Shin, Seungwon
    • Transactions of the KSME C: Technology and Education
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    • v.2 no.1
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    • pp.65-72
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    • 2014
  • The purpose of this study is to design a heat insulator for reducing available energy loss in stratified thermal storage tank. Heat insulator is operated by buoyancy effect from density difference between hot and cold water without extra equipment. Analysis model using the Matlab Simulink was developed to estimate the internal temperature distribution in thermal storage tank and also used to select proper material and thickness of the heat insulator. Operational feasibility was confirmed through reduced scale experiment. As a result, heat insulator can effectively delay the formation of thermal boundary layer between hot and cold water. In reduced scale experiment, heat insulator can preserve additional 1540J of available energy. When applied to the real thermal storage tank, increase of 6% thermal storage efficiency can be expected.

Studies on Molding Conditions and Physical Properties of EMC(Epoxy Molding Compounds) fiiled with Crystalline SiO2 for Microelectronic Encapsulation (결정성 SiO2 충진 EMC(Epoxy Molding Compounds)봉지재의 성형조건 및 물성에 관한 연구)

  • Kim, Wonho;Bae, Jong-Woo;Kang, Ho-young;Lee, Moo-Jung;Choi, II-Dong
    • Applied Chemistry for Engineering
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    • v.8 no.3
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    • pp.533-542
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    • 1997
  • Due to the trends of faster and denser circuit design, dielectric properties of packaging materials for semiconductor will give a greater influence on performance and reliability. Also as chip becomes more densified, thermal dissipation becomes a critical reliability issue. Consequently, four important properties for manufacturing semiconductor packaging materials are low values of dielectric constant, high values of thermal conductivity, relatively low values of thermal expansion coefficient and low cost. Thus, in this study, to achieve increased performance of EMC, crystalline silica was selected as the filler for epoxy matrix. As a result, when the volume percent of crystal silica was 60~70%, good properties as packaging materials for semiconductor were achieved. In addition, overall molding condition of EMC in this experiment was established.

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Numerical Simulation of Heat Transfer in Chip-in-Board Package (Chip-in-Board 패키지의 열전달 해석)

  • Park, Joon Hyoung;Shim, Hee Soo;Kim, Sun Kyoung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.1
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    • pp.75-79
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    • 2013
  • Demands for semiconductor devices are dramatically increasing, and advancements in fabrication technology are allowing a step-up in the number of devices per unit area. As a result, semiconductor devices require higher heat dissipation, and thus, cooling solutions have become important for guaranteeing their operational reliability. In particular, in chip-in-board packages, in which chips and passives are embedded in the substrates for efficient device layout, heat dissipation is of greater importance. In this study, a thermal model for layers of different materials has been proposed, and then, the heat transfer has been simulated by imposing a set of appropriate boundary conditions. Heat generation can be predicted based on the results, which will be utilized as practical data for actual package design.

방전플라즈마 소결법으로 제조한 Mo-Cu 합금 소결체의 물성 및 전기적 특성에 관한 연구

  • Lee, Han-Chan;Mun, Gyeong-Il;Lee, Bung-Ju;Sin, Baek-Gyun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.277-277
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    • 2011
  • Mo-Cu 합금은 고강도이고 우수한 열전도성 및 전기전도성를 가지는 특성이 있어 현재 방열소재, 반도체 부품, 자동차 부품 등 여러 응용분야에서 연구가 활발히 진행되고 있다. 본 연구에서는 서로 고용성이 없는 Mo-Cu 합금을 제조하기 위해서 Mo, Cu 분말을 PBM (Planetary Ball Milling) 방법을 이용하여 제조 하였으며, 제조된 분말은 SPS (Spark Plasma Sintering) 공정을 이용하여 소결체를 제조하였다. Mo-Cu의 조성 변화는 Cu의 함유량을 각각 5at%Cu, 10at%Cu, 20at%Cu로 조절하여 수행하였으며, PBM 의 공정 변수로 회전수(RPM), 볼과 분말의 비율, 분산제의 양, 볼밀 시간, 분위기 변화를 주어 최적조건을 얻기 위한 실험을 진행하였다. PBM 방법을 이용하여 제조한 분말은 PSA (Particle Size Analysis)에 의해 분말의 크기를 측정하고 EDS(Energy Disperse X-ray Spectrometer) 분석에 의해 조성을 확인하였으며, XRD (X-Ray Diffraction) 분석에 의해 Cu peak이 사라지는 조건을 PBM의 최적조건으로 잡고 실험을 진행하였다. 소결체를 고밀도화하기 위해 소결공정을 SPS 방식으로 하였으며 소결체의 경도, 내마모성, 마찰계수 일함수 등을 분석하기 위해 소결체의 크기를 직경 30 mm 및 두께 5 mm로 설계하였고, 소결 공정 변수로 소결온도를 각각 $900^{\circ}C$, $1000^{\circ}C$, $1100^{\circ}C$, 소결압력을 50MPa, 60MPa, 70MPa, 유지시간을 0분, 10분, 20분으로 차이를 주어, 소결체의 밀도차이와 물성차이를 분석하였다. 그 결과 PBM의 최적조건으로는 5at%Cu 에서는 10h, 10at%Cu, 20at%Cu 에서는 20h의 최적의 밀링 시간을 확인하였고, 다른 공정 변수의 최적조건으로는 회전수 300RPM, 10:1의 볼과 분말 비, 분산제 4wt%, Ar 분위기라는 조건을 얻을 수 있었다. 각각의 공정변수 변화에 따른 소결체 최적밀도 달성조건, 소결체 물성 및 전기적 특성 등의 상관관계에 관하여 보고한다.

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Numerical Study on the Thermal Control Device for Satellite Components Using the Phase Change Material Combined with Heat Pipe in Parallel (상변화물질과 열관을 병렬 조합한 위성부품 열제어장치의 수치해석적 연구)

  • Shin, Yoon Sub;Kim, Tae Su;Kim, Taig Young;Seo, Young Bae;Seo, Jung-gi;Hyun, Bum-Seok;Cheon, Hyeong Yul
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.4
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    • pp.373-379
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    • 2016
  • The thermal control device for the periodic working component combined solid-liquid phase change material (PCM) with heat pipes is designed and numerically studied. Due to high latent heat and retaining constant temperature during melting process the component peak temperature, not withstanding small radiator size, is reduced. The warm-up heater power consumption to keep the minimum allowed temperature is also cut down since the accumulated thermal energy is released through the solidification. The thermal buffer mass (TBM) made of Al can give the similar effect but the mass and power consumption of warm-up heater should increase compared to PCM. The amount of PCM can be optimized depending on the component heat dissipation and on/off duty time.

Mechanical and Thermal Characteristics of Cement-Based Composite for Solar Thermal Energy Storage System (태양열 에너지 저장시스템 적용을 위한 시멘트 기반 복합재료의 역학 및 열적 특성)

  • Yang, In-Hwan;Kim, Kyoung-Chul
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.4
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    • pp.9-18
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    • 2016
  • The thermal and mechanical properties of fiber-reinforced cement-based composite for solar thermal energy storage were investigated in this paper. The effect of the addition of different cement-based materials to Ordinary Portland cement on the thermal and mechanical characteristics of fiber-reinforced composite was investigated. Experiments were performed to measure mechanical properties including compressive strength before and after thermal cycling and split tensile strength, and to measure thermal properties including thermal conductivity and specific heat. Test results showed that the residual compressive strength of mixtures with OPC and slag was greatest among cement-based composite. Thermal conductivity of mixtures including graphite was greater than that of any other mixtures, indicating favor of graphite for improving thermal transfer in terms of charging and discharging in thermal energy storage system. The addition of CSA or zirconium increased specific heat of fiber-reinforced cement-based composite. Test results of this study could be actually used for the design of thermal energy storage system in concentrating solar power plants.

Development of a PTC Heater for Supplementary Heating in a Diesel Vehicle (디젤 차량의 보조 난방을 위한 PTC 히터 개발)

  • Shin, Yoon Hyuk;Kim, Sung Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.666-671
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    • 2014
  • Using positive temperature coefficient (PTC) heater as supplementary heating for diesel engine vehicles with low heat source is a good method to enhance the heating performance during cold start. In this study, the PTC elements were made by using screen printing process for forming ohmic contact layer, and prototype of PTC heater was designed and made for a diesel engine vehicle. In process of designing the PTC heater, the thermal flow analysis of PTC element modules was conducted for verifying the effect of the shapes of contact surface between each of the components (cooling fin, insulator, ceramic element). We also investigated the performance characteristic (heating capacity, energy efficiency, pressure drop) of the PTC heater through the experiments. Therefore, the experimental results indicated that prototype of PTC heater had satisfactory performance. This study will be basis for improving the manufacturing process and increasing the performance of the PTC element and heater.

Development of a 3 kW Grid-tied PV Inverter With GaN HEMT Considering Thermal Considerations (GaN HEMT를 적용한 3kW급 계통연계 태양광 인버터의 방열 설계 및 개발)

  • Han, Seok-Gyu;Noh, Yong-Su;Hyon, Byong-Jo;Park, Joon-Sung;Joo, Dongmyoung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.26 no.5
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    • pp.325-333
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    • 2021
  • A 3 kW grid-tied PV inverter with Gallium nitride high-electron mobility transistor (GaN HEMT) for domestic commercialization was developed using boost converter and full-bridge inverter with LCL filter topology. Recently, many GaN HEMTs are manufactured as surface mount packages because of their lower parasitic inductance characteristic than standard TO (transistor outline) packages. A surface mount packaged GaN HEMT releases heat through either top or bottom cooling method. IGOT60R070D1 is selected as a key power semiconductor because it has a top cooling method and fairly low thermal resistances from junction to ambient. Its characteristics allow the design of a 3 kW inverter without forced convection, thereby providing great advantages in terms of easy maintenance and high reliability. 1EDF5673K is selected as a gate driver because its driving current and negative voltage output characteristics are highly optimized for IGOT60R070D1. An LCL filter with passive damping resistor is applied to attenuate the switching frequency harmonics to the grid-tied operation. The designed LCL filter parameters are validated with PSIM simulation. A prototype of 3 kW PV inverter with GaN HEMT is constructed to verify the performance of the power conversion system. It achieved high power density of 614 W/L and peak power efficiency of 99% for the boost converter and inverter.