• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.8
• /
• pp.1100-1106
• /
• 2010

LED(Light Emitting Diode) has the defects of low efficiency and reducement of life cycle as its temperature increases. This research is about an efficient temperature control of the LED. For LED temperature control, it is shown that a heat sink, fan, a one-chip microprocessor and the PID control algorithm are a good cooling system through experiments. Finally. by using the fan as a cooling device and controlling it appropriately, it is proved that the intensity of illumination and the desired temperature can be achieved with consumption of only 2% of the driving power of the LED system through control experiments.

• 전자공학회논문지 IE
• /
• v.48 no.2
• /
• pp.12-18
• /
• 2011

In this paper, did numerical simulation to confirm LED module for lighting and protection against heat special quality of heat sink device. Analysis was gone dividing on case that emitting light side turns normalcy department considering that eat of device according to usage and case that turn down looking being street lamp of 200 W or security appointment lighting device analysis case, and also, volume of thermal element divides on big case and small case and analyzed. Confirmed that can do so that may discharge LED's thermal value to outside enough in analysis wave and current heat sink shape, and investigated that difference of protection against heat performance according to position of device and size of thermal element appears.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.1
• /
• pp.53-60
• /
• 2016

This study discusses the thermal insulation capacity of variant of NO96 LNG (liquefied natural gas) cargo containment insulation system. Changing the insulation materials and the insulation layers of conventional GTT NO96 containment system, The thermal resistance and BOR(boil off rate) caused by the heat transfer between cryogenic and environmental temperature is discussed. Therefore, thermal analysis of LNG CCS(cargo containment system) is carried out to determine the insulation capabilities. Also, BOR is evaluated in terms of the total amount of heat invaded into CCS(cargo containment system). Variant of NO96 CCS such as NO96, NO96GW and NO96L3 membrane type during laden voyage is selected for the comparative study. Finite element model for heat transfer analysis is conducted by employing the equivalent thermal resistance model to simplify the complex insulation layers. Finally the results for each variant model are relatively compared and discussed to minimize the BOR.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.12
• /
• pp.8140-8146
• /
• 2015

The objective of this study is to experimentally investigate the cooling performance characteristics with the consideration of the temperature variations of the enclosure of the 400W ferrofluid active speaker having both woofer and amplifier heat sinks. In order to do this, the heat sinks for both woofer and amplifier was designed ant applied to 400W ferrofluid active speaker. As a result, the cooling performance of the developed 400W ferrofluid active speaker was improved and the temperature of the enclosure after 120 min at steady state increased by $2.8^{\circ}C$ with the increase of the outdoor temperatures from $25^{\circ}C$ to $29^{\circ}C$. In addition, the overall sound pressure level of the developed 400W ferrofluid active speaker showed 111.8 dB and improved 1.9 dB higher than 109.9 dB of the existed speaker.

• Journal of computational fluids engineering
• /
• v.19 no.4
• /
• pp.86-93
• /
• 2014

Increased demand of power-transformer's capacity inevitably results in an excessive temperature rise of transformer components, which in turn requires improved radiator design. In this paper, numerical simulation of the cooling performance of an ONAN-type (Oil Natural Air Natural) radiator surrounded by air was performed by using CFX. The natural convection of the air was treated with the full-model. The present parametric study considers variation of important variables that are expected to affect the cooling performance. We changed the pattern and cross-sectional area of flow passages, the fin interval, the flow rate of oil and shape of flow passages. Results show that the area of flow passage, the fin interval, the flow rate of oil and shape of flow passages considerably affect the cooling performance whereas the pattern of flow passages is not so much influential. We also found that for the case of the fin interval smaller than the basic design, the temperature drop decreases while a larger interval gives almost unchanged temperature drop, indicating that the basic design is optimal. Further, as the flow rate of oil increases, the temperature drop slowly decreases as expected. On the other hand, when the shape of flow passages are changed, temperature drop is increased, indicating that the cooling performance is enhanced thereupon.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.4
• /
• pp.285-291
• /
• 2017

In this study, a case analysis for thermal design of electronic equipment using a phase change material(PCM) was performed numerically using ANSYS Fluent. Experiments were conducted to find the temperature increase(${\Delta}T_m$), melting temperature($T_m$), and volume expansion of the PCM under the melting process. To verify the accuracy of the Fluent solver model, $T_m$, ${\Delta}T_m$, and the melting time were compared with experimental results. To simulate the temperature stagnation phenomenon under the melting process, the equivalent specific heat method was applied to calculate the thermal properties of the PCM in the solver model. To determine the thermal stability of electronic equipment, we paid special attention to finding a thermal design for the PCM using fins. Further, an additional numerical analysis is currently underway to find an optimum design.

• Proceedings of the KSME Conference
• /
• 2001.06d
• /
• pp.280-285
• /
• 2001

This paper presents a modelling of thermal discharge performance for a static ice-on-coil ice-storage tank. Through the present study, discharging characteristics were examined with the existing results of theoretical and numerical heat transfer analyses. Also, an experiment was conducted to obtain a real set of discharge performance. The thermal effectiveness, the ratio of the actual heat transfer rate to the maximum possible heat transfer rate, decreased when the stored energy decreased during discharging period. And the effectiveness increased as the coolant flow rate through the storage increased, of which increasing rate decreased abruptly near the maximum and the minimum stored energy. An empirical correlation was obtained from the experimental and the numerical analysis data.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.9
• /
• pp.2486-2493
• /
• 1994

Transient heat transfer characteristics in th radiant heating panel with heat diffusion fin were predicted by numerical analysis. Thermal behaviors of panel, such as temperature distributions in panel and convective and radiative heat fluxes in panel surface with advance of time, were obtained for several important parameters. The performance and thermal comfort of heating panel were studied and compared for various design conditions, such as pipe pitch, area ratio and thermal conductivity of optimal design of the new heating panels with heat diffusion fin. It was concluded that the efficient area ratio of heat diffusion fin is about 0.5, and the greater the thermal conductivity of fin is, the better the performance of panel is.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2012.06a
• /
• pp.205-205
• /
• 2012

선박에서는 화재안전목표를 달성하기 위해 선박을 방화구획화 함으로써 발화의 지점에서 화재를 차단하여 인근지역으로 확산 되지 않도록 하고 있다. 또한 방화구획을 관통하는 파이프, 덕트 및 전선관통부 등을 통하여 유독가스 및 화염이 순식간에 이동하게 되며, 한쪽 구역에서 발생한 화재의 영향이 다른 구역으로 영향을 미치게 되므로 화염에 의한 피해를 방지하고 불길을 차단하기 위하여 관통부재에 대하여 해당 방화구획과 동등한 성능을 요구하고 있다, 선박에 적용되고 있는 방화구획의 등급은 용도에 따라 일반 상선 등에는 "C ~ A"급, 해양플랜트에는 "C ~ H"급 등급이 요구되고 있다. 그러나 현재 국내 선박 기자재 제작 기술은 "A"급에 머물러 있고 최근 국내 조선소의 해양플랜트 수주 증가와 해양플랜트로의 사업전환으로 관련기자재기업에서 "H"급 기자재 개발에 많은 관심을 가지고 개발 시도를 하고 있다. 이에 본 논문에서는 "H" 급 방화구획에 적용되고 있는 탄화수소계(Hydrocarbon Fire) 내화시험기준과 "H"급 Fire Damper의 단열두께에 따른 탄화수소계(Hydrocarbon Fire) 내화성능실험을 통한 방화 댐퍼의 비 노출면에 대한 방열성능 확보방안에 대하여 언급하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.10
• /
• pp.1011-1019
• /
• 2015

Insulated-gate bipolar transistors (IGBTs) are the predominantly used power semiconductors for high-current applications, and are used in trains, airplanes, electrical, and hybrid vehicles. IGBT power modules generate a considerable amount of heat from the dissipation of electric power. This heat generation causes several reliability problems and deteriorates the performances of the IGBT devices. Therefore, thermal management is critical for IGBT modules. In particular, realizing a proper thermal design for which the device temperature does not exceed a specified limit has been a key factor in developing IGBT modules. In this study, we investigate the thermal behavior of the 1200 A, 3.3 kV IGBT module package using finite-element numerical simulation. In order to minimize the temperature of IGBT devices, we analyze the effects of various packaging materials and different thickness values on the thermal characteristics of IGBT modules, and we also perform a design-of-experiment (DOE) optimization