The Experts below are selected from a list of 24369 Experts worldwide ranked by ideXlab platform
Kwansoo Lee - One of the best experts on this subject based on the ideXlab platform.
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thermal performance and orientation effect of an inclined cross cut cylindrical Heat Sink for led light bulbs
International Journal of Heat and Mass Transfer, 2016Co-Authors: Seungjae Park, Daeseok Jang, Kwansoo LeeAbstract:Abstract An inclined cross-cut cylindrical Heat Sink was investigated in an attempt to improve the energy conversion and management of LED light bulbs. The thermo-flow characteristics were studied to enhance the cooling performance of a cylindrical Heat Sink, which is the cooling apparatus used for LED light bulbs. In the inclined cross-cut Heat Sink, the natural convection flow with an incidence angle had a flow path length that was more stretched in comparison to the flow path length of a straight cross-cut Heat Sink. Accordingly, the Heat transfer rate between the air and fins was increased. When the fins had an inclined angle of 25–30°, the thermal resistance was the smallest. However, when the inclined angle increased to greater than 50°, only the blocking effect was increased and the flow path length was not stretched. Hence, cooling performance was decreased with inclined angles greater than 50°. A correlation predicting the degree of improvement in cooling performance relative to a baseline straight cross-cut Heat Sink was suggested as a function of Heat Sink design variables and the installation angle of the Heat Sink. Finally, a contour map was developed, which can be used to select the optimum Heat Sink type, with respect to the installation angle of the Heat Sink and the inclined angle of the fins.
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optimization of a chimney design for cooling efficiency of a radial Heat Sink in a led downlight
Energy Conversion and Management, 2016Co-Authors: Seungjae Park, Se-jin Yook, Daeseok Jang, Kwansoo LeeAbstract:Abstract A cooling system, consisting of a chimney and a radial Heat Sink, was developed for a light-emitting diode (LED) downlight to replace a conventional light for saving energy. Natural convection was simulated with a numerical model that was verified experimentally. When the chimney was installed around the radial Heat Sink, the cooling efficiency of the Heat Sink was improved because the cooling air was able to move to the center of the Heat Sink. Furthermore, the mass of the surrounding structure could be reduced due to the superior geometric characteristics of the chimney versus a hollow cylinder. The effects of the fin-type of the radial Heat Sink and the thermal conductivity of the chimney were analyzed. A parametric study of the geometric factors of the chimney was conducted and a multidisciplinary design optimization, which considered the chimney mass and cooling efficiency of the Heat Sink, was carried out. Consequently, installing the chimney can improve the Heat Sink’s cooling efficiency by up to 20% (while maintaining the mass of the surrounding structure) or reduce the mass of the surrounding structure by up to 60% (for a given cooling efficiency), as compared to the installation of the hollow cylinder.
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thermal performance improvement of a radial Heat Sink with a hollow cylinder for led downlight applications
International Journal of Heat and Mass Transfer, 2015Co-Authors: Seungjae Park, Daeseok Jang, Kwansoo LeeAbstract:Abstract A cooling system consisting of a hollow cylinder and a radial Heat Sink that can be applied to a light-emitting diode (LED) downlight is suggested. Natural convection Heat transfer is simulated via a numerical model and validated experimentally. The airflow pattern around the radial Heat Sink is similar to that of a chimney, entering from the side of the Heat Sink and moving upward. When the hollow cylinder is installed, the mass flow rate of air to the Heat Sink fins increases, which results in enhanced thermal performance of the Heat Sink. The effect of the size, set up height and material of the hollow cylinder is analyzed, and the performance of Heat Sinks with various fin-types is calculated. The results show that the thermal performance of a radial Heat Sink is enhanced by up to 43% following installation of a hollow cylinder.
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optimization of a staggered pin fin for a radial Heat Sink under free convection
International Journal of Heat and Mass Transfer, 2015Co-Authors: Seungjae Park, Se-jin Yook, Daeseok Jang, Kwansoo LeeAbstract:Abstract The design of a staggered pin-fin radial Heat Sink was optimized for light-emitting diode (LED) device cooling. A numerical model for various pin-fin array Heat Sinks was developed and verified experimentally. The design variables were determined from sensitivity analysis. Multidisciplinary optimization was conducted based on the Heat Sink thermal resistance and mass, using an evolutionary algorithm. From the analysis results, the staggered pin-fin radial Heat Sink was identified as the optimal configuration, demonstrating improved thermal performance by up to 10% while maintaining the same mass or reducing the mass by up to 12% for a given thermal resistance.
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correlation of cross cut cylindrical Heat Sink to improve the orientation effect of led light bulbs
International Journal of Heat and Mass Transfer, 2015Co-Authors: Daeseok Jang, Dong Rip Kim, Kwansoo LeeAbstract:Abstract We investigate cross-cut cylindrical Heat Sink to improve cooling of a light-emitting diode (LED) bulb compared with conventional plate-fin cylindrical Heat Sinks using various installation angles. In contrast to plate-fin Heat Sinks, whereby the fins in the upper Heat Sink do not provide effective cooling at large installation angles, flow formed between the cross-cut fins and the air reached the upper region of the Heat Sink. As the installation angle increased, the length of the flow path increased. Accordingly, the flow efficiency of the cooling air improved, and the dependence of the cooling on orientation was reduced. The improvement of the cross-cut Heat Sink was more noticeable in the shorter cross-cut length. We suggest a correlation to predict the degree of improvement in the thermal resistance compared with a plate-fin Heat Sink as a function of design parameters and installation angle, and develop a contour map describing the optimum Heat Sink shape for various installation angles.
Jerhuan Jang - One of the best experts on this subject based on the ideXlab platform.
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the Heat transfer characteristics of liquid cooling Heat Sink with micro pin fins
International Communications in Heat and Mass Transfer, 2017Co-Authors: Hanchieh Chiu, Renhorn Hsieh, Kai Wang, Jerhuan JangAbstract:Abstract This paper numerically and experimentally investigated the liquid cooling efficiency of Heat Sinks containing micro pin fins. Aluminum prototypes of Heat Sink with micro pin fin were fabricated to explore the flow and thermal performance. The main geometry parameters included the diameter of micro pin fin and porosity of fin array. The effects of the geometrical parameters and pressure drop on the Heat transfer performance of the Heat Sink were studied. In the experiments, the Heat flux from base of Heat Sink was set as 300 kW/m2. The pressure drop between the inlet and the outlet of Heat Sink was set
Jing Liu - One of the best experts on this subject based on the ideXlab platform.
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flow and thermal modeling and optimization of micro mini channel Heat Sink
Applied Thermal Engineering, 2017Co-Authors: Xiaohu Yang, Sicong Tan, Yujie Ding, Jing LiuAbstract:Abstract This paper is dedicated to present a comprehensive comparison and discussion on the flow and thermal modeling of micro/mini-channel Heat Sink for better understanding and further sophistication of this technology. A general optimization process for the flow and thermal performance of micro/mini-channel Heat Sink is developed, for water cooling and liquid metal cooling both in micro scale and millimeter scale together. Numerical calculation is adopted in the optimization process and serves as baseline for the comparison of different correlations, while 1D thermal resistance model is used for thermal analysis. Appropriate correlations are recommended and optimal parameter selections and suggestions are provided for practical design. Liquid metal cooling and water cooling are compared in mini-channel Heat Sink, the former exhibits much superior flow and thermal performance. For water cooling, 1D model works well. While for liquid metal cooling, significant deviation exists between the model and the numerical results, and more experimental and analytical works are needed for the thermal design of this kind of coolant.
Liang Gong - One of the best experts on this subject based on the ideXlab platform.
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thermal performance of metal foam Heat Sink with pin fins for non uniform Heat flux electronics cooling
2019 35th Semiconductor Thermal Measurement Modeling and Management Symposium (SEMI-THERM), 2019Co-Authors: Liang Gong, Yogendra JoshiAbstract:In this paper, a concept of metal foam Heat Sink with pin fins (MFPF Heat Sink) is presented to improve the cooling performance of high powered electronics with non-uniform Heat flux. Numerical simulation is carried out to investigate the MFPF Heat Sink on the thermal and hydraulic performances in comparison to metal foam Heat Sink, and traditional pin fin Heat Sink. The thermal effectiveness of MFPF Heat Sink is demonstrated by comparing its temperature control capability with the baseline configurations. Based on this, the MFPF Heat Sink is employed to remove the non-uniform Heat flux to ensure the electronic devices operation below a specified maximum temperature. MFPF Heat Sink under several different power levels are also examined. Results show that MFPF Heat Sink effectively improves the thermal performance and make the bottom wall temperature more uniform. The thermal performance of metal foam Heat Sink is more sensitive to porosity than pore density. A local Heat flux of 100 $\mathrm{W}/\mathrm{c}\mathrm{m}^{2}$ is successfully dissipated using the proposed MFPF Heat Sink with the junction temperature below $90^{\circ}\mathrm{C}$.
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thermal performance of micro channel Heat Sink with metallic porous solid compound fin design
Applied Thermal Engineering, 2018Co-Authors: Liang Gong, Zhang BaiAbstract:Abstract Rapid development of large-scale integrations of electronic circuits resulted in increasing requirements for chip power dissipation. In this study, a concept of micro-channel Heat Sink with the metallic porous/solid compound fin design was developed and numerically investigated. Computational investigations were carried out to analyze the effects of metallic porous fins on the hydraulic and thermal performances, and to determine the optimal dimensionless porous fin thickness for designing the porous/solid compound fins. The traditional solid fin Heat Sink is selected as the comparison model. The results indicate that the viscous shear stress is reduced at the fluid and porous fin interfaces, which leads to decreased pressure drop through the porous fin Heat Sink. Whereas, the Heat transfer performance deteriorates when the solid fins are completely replaced by the porous fins. The novel design of porous/solid compound fin demonstrates more favorable in the hydraulic and thermal performances. Both the pressure drop and the overall thermal resistance are substantially decreased, and the optimal dimensionless porous fin thickness for the compound fin Heat Sink is approximately 0.2. The presented compound fin Heat Sink is capable of effectively enhancing the cooling performance for high-powered electronics.
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numerical study and optimizing on micro square pin fin Heat Sink for electronic cooling
Applied Thermal Engineering, 2016Co-Authors: Jin Zhao, Liang Gong, Shanbo Huang, Zhaoqin HuangAbstract:Abstract Micro pin-fin Heat Sink, characterized by low thermal resistance, compact structure and uniform temperature distribution along the flow direction, is effective and valuable for thermal management of electronic devices. To enhance the cooling performance of the micro square pin-fin Heat Sink, a geometry optimizing method changing pin-fin porosity and pin-fin located angle is proposed in this paper. The flow and Heat transfer characteristics were studied numerically and the geometry of the micro square pin-fin Heat Sink was optimized. To reveal the characteristics and advantages of the micro square pin-fin Heat Sink, the comparison between the square pin-fin and the column pin-fin was made. Numerical results indicate that both the pin-fin porosity and located angle are important for the cooling capacity and thermal performance of the micro square pin-fin Heat Sink; the optimal porosity and located angle for thermal performance are 0.75 and 30° respectively. Furthermore, micro Heat Sinks with the optimized square pin-fin present better thermal performance than micro column pin-fin Heat Sinks, which implies that there is great potential to employ micro square pin-fin Heat Sinks for thermal management on electronic devices with high energy density.
Xiaohu Yang - One of the best experts on this subject based on the ideXlab platform.
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evaluation and optimization of low melting point metal pcm Heat Sink against ultra high thermal shock
Applied Thermal Engineering, 2017Co-Authors: Xiaohu Yang, Zhizhu He, Yixin ZhouAbstract:Abstract In this paper, the low melting point metal phase change material (PCM) Heat Sink for coping with ultra-high thermal shock (102 W/cm2) is developed and optimized theoretically and numerically. Gallium is selected as the best PCM candidate from the point of view of thermal performance based on an approximate theoretical analysis, and gallium based PCM Heat Sink with internal copper fin is configured. Different fin structures, namely plate fin, crossed fin and pin fin are investigated and compared; the effects of fin number, fin width and base thickness are parametrically studied; the influence of the structural material is briefly discussed. For arbitrarily given Heating condition, the optimal geometric configuration of the Heat Sink is suggested and corresponding thermal performance is provided. The proposed low melting point metal PCM Heat Sink can cope with very large thermal shock like 100 W/cm2 (1 s) with maximum device temperature of 46 °C, under the ambient temperature of 25 °C, which is extremely difficult to deal with otherwise by conventional PCMs. The conclusions drawn in this paper can serve as valuable reference for thermal design and analysis of PCM Heat Sink against ultra-high thermal shock.
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flow and thermal modeling and optimization of micro mini channel Heat Sink
Applied Thermal Engineering, 2017Co-Authors: Xiaohu Yang, Sicong Tan, Yujie Ding, Jing LiuAbstract:Abstract This paper is dedicated to present a comprehensive comparison and discussion on the flow and thermal modeling of micro/mini-channel Heat Sink for better understanding and further sophistication of this technology. A general optimization process for the flow and thermal performance of micro/mini-channel Heat Sink is developed, for water cooling and liquid metal cooling both in micro scale and millimeter scale together. Numerical calculation is adopted in the optimization process and serves as baseline for the comparison of different correlations, while 1D thermal resistance model is used for thermal analysis. Appropriate correlations are recommended and optimal parameter selections and suggestions are provided for practical design. Liquid metal cooling and water cooling are compared in mini-channel Heat Sink, the former exhibits much superior flow and thermal performance. For water cooling, 1D model works well. While for liquid metal cooling, significant deviation exists between the model and the numerical results, and more experimental and analytical works are needed for the thermal design of this kind of coolant.
