Micro-pin-fin cooler mounted on the power chip enables the heat removal to meet modern microsystem requirement. Carbon nanotubes （CNTs） have been proven as a potential material for micro-coolers due to the superior ...Micro-pin-fin cooler mounted on the power chip enables the heat removal to meet modern microsystem requirement. Carbon nanotubes （CNTs） have been proven as a potential material for micro-coolers due to the superior thermal conductivity, good mechanical property and so forth, and there appear various applications of CNTs in the micro-cooler technology. In the present paper, an analysis of the thermal and hydraulic characteristics of the micro-pin-fin heat sink was conducted, where air was used as the cooling medium and an impinging jet was introduced to enhance the heat transfer. Three-dimension computational fluid dynamics （CFD） simulations were carried out for micro-pin-fin coolers with various parameters, including the pin-fin size and pattern as well as the jet velocity and nozzle diameter. The flow field and thermal properties of the. micro-pin-fin heat sink were obtained, and the heat removal efficiency was evaluated.展开更多
In order to comply with the recent demand for downsizing of the electric equipment, the minia- turization and the improvement in heat transfer performance of a heat sink under natural air-cooling are increasingly requ...In order to comply with the recent demand for downsizing of the electric equipment, the minia- turization and the improvement in heat transfer performance of a heat sink under natural air-cooling are increasingly required. This paper describes the experimental and numerical investigations of heat sinks with miniature/micro pins and the effect of the pin size, pin height and the number of pins on heat transfer characteristics of heat sinks. Five types of basic heat sink models are investigated in this study. The whole heat transfer area of heat sinks having the different pin size, pin height and the number of pins respectively is kept constant. From a series of experiments and numerical analyses, it has been clarified that the heat sink temperature rises with increase in the number of pins. That is, the heat sink with miniaturized fine pins showed almost no effect on the heat transfer enhancement. This is because of the choking phenomenon occurred in the air space among the pin fins. Reflecting these results, it is confirmed that the heat transfer coefficient reduces with miniaturization of pins. Concerning the effects of the heat transfer area on the heat sink performance, almost the same tendency has been observed in other three series of large surface area, that is, higher pin height. Furthermore as a result of studying non-dimensional convection heat transfer performance, it was found that the relation between the Nusselt number (Nu) and the Rayleight number (Ra) is given by Nu = 0.16 Ra0.52.展开更多
Considering the limitation in current manufacturing technology of commercial pin fin heat sinks,a new fabric heat sink has been designed. However,it is lack of an understanding of the heat transferring performance of ...Considering the limitation in current manufacturing technology of commercial pin fin heat sinks,a new fabric heat sink has been designed. However,it is lack of an understanding of the heat transferring performance of this new kind of heat sink. In this study,the finite element method (FEM) was used to predict the heat transferring performance of fabric heat sink under the condition of natural convection and forced convection, and its heat transferring performance was compared with that of pin fin heat sink. The results showed that in the condition of natural convection the heat transferring performance of pin fin heat sink was better than that of fabric heat sink, and vice versa under the forced convection condition.展开更多
Considering current technology limitation in manufacturing present pin fin heat sinks, a new fabric heat sink has been previously designed. However, there is a lack of an understanding of the heat transferring perform...Considering current technology limitation in manufacturing present pin fin heat sinks, a new fabric heat sink has been previously designed. However, there is a lack of an understanding of the heat transferring performance of this new kind of heat sink. Nowadays, finite element analysis has been generally developed for determining heat transfer from in-line and staggered pin fin heat sinks used in electronic packaging applications. In this study, this method is used to predict the heat transfer performance of the new heat sink with woven fabric structure, called fabric pin fin heat sink. Effect of the fin length and the material types made of heat sink on the thermal-structure response of the pin fin was investigated under forced convection. The results show that the minimum temperature of heat sink decreases with an increase of pin fin length,but the decreasing amplitude has decreased. Moreover, the heat transfer performance of fabric heat sink made of continuous carbon Fibers/Polymer (PPS) is worse than that of copper and of aluminum.展开更多
Heat transfer in passage with pin-fin arrays for cooling blade trailing edge was studied numerically. Three-dimensional numerical simulations were carried out for steady laminar flow in passages with different wedge a...Heat transfer in passage with pin-fin arrays for cooling blade trailing edge was studied numerically. Three-dimensional numerical simulations were carried out for steady laminar flow in passages with different wedge angles between pressure surface and suction surface of cooling blade trailing edge to study the effect of different wedge angles (from 0°to 30°) on heat transfer and pressure losses. Research was carried out for both in-line array and staggered array. From this investigation, wedge angle 10°gives the best heat transfer performance.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.10702037)the National High-Technology Research and Development Program(Grant No.2008AA04Z301)
文摘Micro-pin-fin cooler mounted on the power chip enables the heat removal to meet modern microsystem requirement. Carbon nanotubes （CNTs） have been proven as a potential material for micro-coolers due to the superior thermal conductivity, good mechanical property and so forth, and there appear various applications of CNTs in the micro-cooler technology. In the present paper, an analysis of the thermal and hydraulic characteristics of the micro-pin-fin heat sink was conducted, where air was used as the cooling medium and an impinging jet was introduced to enhance the heat transfer. Three-dimension computational fluid dynamics （CFD） simulations were carried out for micro-pin-fin coolers with various parameters, including the pin-fin size and pattern as well as the jet velocity and nozzle diameter. The flow field and thermal properties of the. micro-pin-fin heat sink were obtained, and the heat removal efficiency was evaluated.
文摘In order to comply with the recent demand for downsizing of the electric equipment, the minia- turization and the improvement in heat transfer performance of a heat sink under natural air-cooling are increasingly required. This paper describes the experimental and numerical investigations of heat sinks with miniature/micro pins and the effect of the pin size, pin height and the number of pins on heat transfer characteristics of heat sinks. Five types of basic heat sink models are investigated in this study. The whole heat transfer area of heat sinks having the different pin size, pin height and the number of pins respectively is kept constant. From a series of experiments and numerical analyses, it has been clarified that the heat sink temperature rises with increase in the number of pins. That is, the heat sink with miniaturized fine pins showed almost no effect on the heat transfer enhancement. This is because of the choking phenomenon occurred in the air space among the pin fins. Reflecting these results, it is confirmed that the heat transfer coefficient reduces with miniaturization of pins. Concerning the effects of the heat transfer area on the heat sink performance, almost the same tendency has been observed in other three series of large surface area, that is, higher pin height. Furthermore as a result of studying non-dimensional convection heat transfer performance, it was found that the relation between the Nusselt number (Nu) and the Rayleight number (Ra) is given by Nu = 0.16 Ra0.52.
基金The Fundamental Research Funds for the Central Universities,China
文摘Considering the limitation in current manufacturing technology of commercial pin fin heat sinks,a new fabric heat sink has been designed. However,it is lack of an understanding of the heat transferring performance of this new kind of heat sink. In this study,the finite element method (FEM) was used to predict the heat transferring performance of fabric heat sink under the condition of natural convection and forced convection, and its heat transferring performance was compared with that of pin fin heat sink. The results showed that in the condition of natural convection the heat transferring performance of pin fin heat sink was better than that of fabric heat sink, and vice versa under the forced convection condition.
文摘Considering current technology limitation in manufacturing present pin fin heat sinks, a new fabric heat sink has been previously designed. However, there is a lack of an understanding of the heat transferring performance of this new kind of heat sink. Nowadays, finite element analysis has been generally developed for determining heat transfer from in-line and staggered pin fin heat sinks used in electronic packaging applications. In this study, this method is used to predict the heat transfer performance of the new heat sink with woven fabric structure, called fabric pin fin heat sink. Effect of the fin length and the material types made of heat sink on the thermal-structure response of the pin fin was investigated under forced convection. The results show that the minimum temperature of heat sink decreases with an increase of pin fin length,but the decreasing amplitude has decreased. Moreover, the heat transfer performance of fabric heat sink made of continuous carbon Fibers/Polymer (PPS) is worse than that of copper and of aluminum.
文摘Heat transfer in passage with pin-fin arrays for cooling blade trailing edge was studied numerically. Three-dimensional numerical simulations were carried out for steady laminar flow in passages with different wedge angles between pressure surface and suction surface of cooling blade trailing edge to study the effect of different wedge angles (from 0°to 30°) on heat transfer and pressure losses. Research was carried out for both in-line array and staggered array. From this investigation, wedge angle 10°gives the best heat transfer performance.
