• Title/Summary/Keyword: Cooling analysis

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A consistent FEM-Vlasov model for hyperbolic cooling towers on layered soil under unsymmetrical wind load

  • Karakas, Ali I.;Ozgan, Korhan;Daloglu, Ayse T.
    • Wind and Structures
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    • v.22 no.6
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    • pp.617-633
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    • 2016
  • In this paper, the analysis of hyperbolic cooling tower on elastic subsoil exposed to unsymmetrical wind loading is presented. Modified Vlasov foundation model is used to determine the soil parameters as a function of vertical deformation profile within subsoil. The iterative parameter updating procedure involves the use of Open Application Programming Interface (OAPI) feature of SAP2000 to provide two way data flow during execution. A computing tool coded in MATLAB employing OAPI is used to perform the analysis of hyperbolic cooling tower with supporting columns over a hollow annular raft founded on elastic subsoil. The analysis of such complex soil-structure system is investigated under self-weight and unsymmetrical wind load. The response of the cooling tower on elastic subsoil is compared with that of a tower that its supporting raft foundation is treated as fixed at the base. The results show that the effect of subsoil on the behavior of cooling tower is considerable at the top and bottom of the wall as well as supporting columns and raft foundation. The application of a full-size cooling tower has demonstrated that the procedure is simple, fast and can easily be implemented in practice.

Thermal Characteristics and Cooling Experiments and Analysis of Finite Elements in the Discharge of Lithium-Ion Batteries (리튬이온 배터리 방전 시 발열 특성 및 냉각 실험과 유한요소 해석)

  • Seokil Kim;Shin You Kang
    • Journal of Industrial Technology
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    • v.43 no.1
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    • pp.15-23
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    • 2023
  • Lithium-ion batteries are predominantly employed in electric vehicles and energy storage devices, offering the advantage of high energy density. However, they are susceptible to efficiency degradation when operated at high temperatures due to their sensitivity to the external environment. In this study, we conducted experiments using an indirect cooling method to prevent thermal runaway and explosions in lithium-ion batteries. The results were validated by comparing them with heat transfer simulations conducted through a commercial finite element analysis program. The experiments included single-cell exothermic tests and cooling experiments on a battery pack with 10 cells connected in series, utilizing 21700 lithium-ion batteries. To block external temperature influences, the experimental environment featured an extrusion method insulation in the environmental chamber. The cooling system, suitable for indirect cooling, was constructed with copper tubes and pins. The heat transfer analysis began by presenting a single-cell heating model using commercial software, which was then employed to analyze the heating and cooling of the battery pack.

Design and transient analysis of a compact and long-term-operable passive residual heat removal system

  • Wooseong Park;Yong Hwan Yoo;Kyung Jun Kang;Yong Hoon Jeong
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4335-4349
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    • 2023
  • Nuclear marine propulsion has been emerging as a next generation carbon-free power source, for which proper passive residual heat removal systems (PRHRSs) are needed for long-term safety. In particular, the characteristics of unlimited operation time and compact design are crucial in maritime applications due to the difficulties of safety aids and limited space. Accordingly, a compact and long-term-operable PRHRS has been proposed with the key design concept of using both air cooling and seawater cooling in tandem. To confirm its feasibility, this study conducted system design and a transient analysis in an accident scenario. Design results indicate that seawater cooling can considerably reduce the overall system size, and thus the compact and long-term-operable PRHRS can be realized. Regarding the transient analysis, the Multi-dimensional Analysis of Reactor Safety (MARS-KS) code was used to analyze the system behavior under a station blackout condition. Results show that the proposed design can satisfy the design requirements with a sufficient margin: the coolant temperature reached the safe shutdown condition within 36 h, and the maximum cooling rate did not exceed 40 ℃/h. Lastly, it was assessed that both air cooling and seawater cooling are necessary for achieving long-term operation and compact design.

Rapid cooling of injection mold for high-curvature parts using CO2 cooling module (CO2 냉각모듈을 적용한 고곡률 성형품의 사출금형 급속냉각)

  • Se-Ho Lee;Ho-Sang Lee
    • Design & Manufacturing
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    • v.16 no.4
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    • pp.67-74
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    • 2022
  • Injection molding is a cyclic process comprising of cooling phase as the largest part of this cycle. Providing efficient cooling in lesser cycle times is of significant importance in the molding industry. Recently, lots of researches have been done for rapid cooling of a hot-spot area using CO2 in injection molding. The CO2 flows under high pressure through small, flexible capillary tubes to the point of use, where it expands to create a snow and gas mixture at a temperature of -79℃. The gaseous CO2 removes heat from the mold and releases it into the atmosphere. In this paper, a CO2 cooling module was applied to an injection mold in order to cool a large area cavity uniformly and quickly, and the cooling performance of the injection mold was investigated. The product was a high-curvature molded part with a molding area of 300x100mm. Heat cartridges were installed in a stationary mold, and CO2 cooling module was inserted inside a movable mold. Through structural analysis, it was confirmed that the maximum deformation of mold with CO2 cooling module was 0.09mm. A CO2 feed system with a heat exchanger was used for cooling experiments. The CO2 was injected into the holes on both sides of the supply pipe of the cooling module and discharged through hexagon blocks to cool the mold. It took 5.8 seconds to cool the mold from an average temperature of 140℃ to 70℃. Through the experiment using CO2 cooling module, it was found that a cooling rate of up to 12.98℃/s and an average of 10.18℃/s could be achieved.

Packaging Design of EPS Cooling Box by Theoretical Heat Flow and Random Vibration Analysis (이론적 열유동 및 랜덤 진동 해석을 적용한 EPS 보냉용기의 포장설계)

  • Kim, Su-Hyun;Park Sang-Hoon;Lee, Min-A;Jung, Hyun-Mo
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.27 no.3
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    • pp.175-180
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    • 2021
  • Although it has recently been regulated for use as an eco-friendly policy in Korea, the use of EPS (Expanded Polystyrene) cooling boxes, which are used as cold chain delivery insulation boxes for fresh agricultural and livestock products, is also increasing rapidly as e-commerce logistics such as delivery have increased rapidly due to COVID-19. Studies were conducted to optimize the EPS cooling container through internal air heat flow of CFD (Computational Fluid Dynamics) analysis and FEM (Finite Element Method) random vibration analysis using domestic PSD (Power Spectral Density) profile of the EPS cooling box to which the refrigerant is applied in this study. In the analysis of the internal air heat flow by the refrigerant in the EPS cooling box, the application of vertical protrusions inside was excellent in volume heat flow and internal air temperature distribution. In addition, as a result of random vibration analysis, the internal vertical protrusion gives the rigid effect of the cooling box, so that displacement and stress generation due to vibration during transport are smaller than that of a general cooling container without protrusion. By utilizing the resonance point (frequency) of the EPS cooling box derived by the Model analysis of ANSYS Software, it can be applied to the insulation and cushion packaging design of the EPS product line, which is widely used as insulation and cushion materials.

Thermal and Flow Analysis of Outer-Rotor Type BLDC Motor with Cooling Blades (냉각날개를 갖는 외전형 BLDC 모터의 열유동 해석)

  • Kang, Soo-Jin;Wang, Se-Myung;Shim, Ho-Kyung;Lee, Kwan-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.9
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    • pp.772-779
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    • 2007
  • In this paper, thermo-flow characteristics of an outer-rotor type BLDC motor are numerically analyzed using three-dimensional turbulence modeling. On the rotor of the BLDC motor, cooling blades and cooling holes are existed for the enhanced cooling performances. Rotating the blades and holes generates axial air flow streaming into inner rotor side and passing through stator slots, which cools down stator by forced convection. Operating tests are performed and the numerical temperature fields are found to be in good agreement with experimental results. A new design of the BLDC motor has also been developed and major design parameters such as the arrangement of cooling holes, the area of cooling holes and cooling blades, and the cooling blade angle, are analyzed for the enhanced convective heat transfer rate. It is found that the convective heat transfer rate of the new BLDC motor model is increased by about 8.1%, compared to that of the reference model.

Development of BLDC Motor for HEV Engine Cooling and Battery Cooling System (하이브리드 차량의 엔진 및 배터리 냉각팬 구동용 BLDC모터 개발)

  • Lee, Daewoong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.2
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    • pp.153-160
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    • 2015
  • Hybrid Electric Vehicles(HEVs) have seriously come into prevalence recently as car manufacturers and consumers have become more aware of the environmental and economic problems of conventional vehicles. For the alternative power-train and battery cooling systems in HEVs, an effective thermal management system is required, and many automakers are interested in using Brushless DC(BLDC) motors for cooling fans for the overall traction unit's performance and energy saving capability. This paper presents the development status of BLDC motors as major parts of the power-train, i.e. the engine cooling and battery cooling fans of HEVs. A design that uses BLDC motors for the power-train and each battery cooling fan, is successfully implemented through using electro-magnetic analysis, and prototype BLDC motors are examined. As experimental results, the BLDC motors achieved an efficiency of 85% as engine cooling fans and 72% as a battery thermal management fan motor. The electric cogging noise is significantly reduced by changing the skew of the slot pitch angle and optimizing the magnetic shape.

Numerical Thermo-Fluid Analysis to the Water Cooling Plate (IGBT 스택용 10kW급 수냉각판 열유동 수치해석)

  • Ryoo, Seong-Ryoul;Mock, Chin-Sung;Cho, Tae-Sik;Kim, Chul-Ju
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1298-1302
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    • 2011
  • The present study deals with the results of a thermo-fluid analysis applied to the cooling plate of the water cooling system developed for IGBT stacks, which was designed to keep the power semi-conductors from over heating problems. The cooling plate is to absorb a maximum quantity of 10kW from 4 IGBTs which are to be placed on both sides of the cooling plate, 2 IGBTs of them on each surface. For the analysis, Adina of CFD Program was used and an analysis was conducted to obtain the knowledges on heat and mass flow at both the plate and fluid flow inside. For the simulation, the operational conditions of a temperature difference of $15^{\circ}C$ for the working fluid and a uniform heat flux of about 92000 $W/m^2$ on the surface in contact with an IGBTs.

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Cooling Performance Analysis of a Sub-scale Calorimeter (축소형 칼로리미터의 냉각성능 해석)

  • 조원국;문윤완
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.3
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    • pp.8-14
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    • 2003
  • A cooling performance analysis has been made in the 8-channel calorimeter based on sub-scale KSR-III engine. Three-dimensional heat transfer analysis in cooling channels has been performed using the heat flux distribution through the chamber wall predicted from axi-symmetric compressible flow inside the combustion chamber. The heat flux distribution is verified against the published literature. Presented for the development and operation of the calorimeter are the coolant pressure drop, coolant temperature rise and the maximum chamber wall temperature. Required coolant flow rate is determined for given chamber pressure. Cooling performance is also predicted for temperature dependant coolant properties.

NUMERICAL STUDY FOR COOLING CAPACITY IMPROVEMENT OF ENGINE ROOM ENCLOSURE SYSTEM (엔진실 차폐 시스템의 냉각성능 개선을 위한 수치적 연구)

  • Bae, Y.S.;Yoo, G.J.;Choi, H.K.
    • Journal of computational fluids engineering
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    • v.14 no.2
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    • pp.39-45
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    • 2009
  • In engine room, proper enclosure system is preferable for reducing noise level but the enclosure system in the engine room causes bad influence on cooling performance due to poor ventilation. Cooling efficiency of the enclosure system can be improved by varying fan speed and proper flow path for ventilation. In this study, numerical analysis is performed to assess cooling effect of the enclosure system using finite volume method. The RNG k-$\varepsilon$ model is adopted for turbulence model along with heat exchanger model and porous media model for heat exchanger analysis, and moving reference frame model for rotational fan. Verification result shows reasonable agreement with experimental data. Analysis results show direct effect of velocity and temperature distribution on cooling ability in the enclosure system. Enclosure system of case B shows high heat transfer coefficient and has the smallest area ratio of opened flow passages which is good for noise level reduction.