基于电流体动力效应的矩形通道内强化换热
发布时间：2018-07-29 18:47
【摘要】：随着科技的发展,电子产品的集成度越来越高,功率越来越大,因此产生的热流密度越来越高。为保证其正常运行,电子产品的热管理问题至关重要。作为一种颇具前景的主动强化换热技术,电流体动力效应(electrohydrodynamics,简称EHD)强化换热以其结构简单、能耗低、噪音小等诸多优点而倍受关注。目前,国内外很多学者已对EHD效应进行了广泛研究。由于其机理复杂,长期以来以实验研究居多。直到最近几十年,才有学者采用数值模拟对EHD诱导的强化换热其进行研究。对上述研究总结归纳后发现,目前尚未全面研究电极横向位置、电极数目和接地电极大小的对通道内换热特性的影响。基于此,本文建立了EHD的多物理耦合模型,并在此基础上,通过新的电极排列设计及相关参数优化,达到增强通道内强化换热特性的目的。通过改变通道中电极的横向位置对传统单壁面换热的通道进行了数值模拟,研究参数包括电极距离通道入口的位置d,电极间距l,电极数目n等。通过数值模拟得出,电极和通道入口距离d越大,电极所形成的漩涡温度越高,通道的强化换热因子ξ越小。电极间距l越大,电极和电极之间的相互影响越小,通道的强化换热因子ξ越大。随着电极数目n的增加,通道的强化换热因子ξ先增大,当数目超过一定值后ξ达到最大值并饱和。在本课题的通道中,这一最大值约为4.8。关于对上下两个壁面都有热流密度的通道,本课题对电极在通道中的位置和接地的方式进行了研究。结果表明将通道中的两个电极分别靠近上下两个壁面,且接地方式采用部分接地时,上下壁面的换热能力都会相对有所提高,并且这一结论不会随着电极的间距L、电极与通道入口的距离d的改变而改变。当改变部分接地角度θ时,电势和电荷密度分布都会改变,电场力也随之改变,从而导致流场和温度场发生相应的变化,通道的换热效果会受到影响。
[Abstract]:With the development of science and technology, the integration and power of electronic products become more and more high, so the heat flux is becoming higher and higher. In order to ensure its normal operation, the thermal management of electronic products is very important. As a promising active enhanced heat transfer technology, electrohydrodynamic effect (EHD) has attracted much attention for its advantages of simple structure, low energy consumption, low noise and so on. At present, many scholars at home and abroad have carried out extensive research on EHD effect. Because of its complex mechanism, experimental research has been the majority for a long time. Only in recent decades has a numerical simulation been used to study the enhanced heat transfer induced by EHD. It is found that the influence of the transverse position of the electrode, the number of the electrode and the size of the grounding electrode on the heat transfer characteristics in the channel has not been fully studied. Based on this, the multi-physical coupling model of EHD is established, and on this basis, through the new electrode arrangement design and the optimization of related parameters, the enhancement of heat transfer characteristics in the channel is achieved. By changing the transverse position of the electrode in the channel, the traditional single-wall heat transfer channel is numerically simulated. The parameters include the position of the electrode from the entrance of the channel, the distance between the electrodes, the number of the electrodes, and so on. The numerical simulation results show that the larger the distance between the electrode and the channel is, the higher the vortex temperature is and the smaller the enhanced heat transfer factor 尉 is. The larger the electrode spacing, the smaller the interaction between the electrode and the electrode, and the greater the enhancement heat transfer factor 尉 of the channel. With the increase of electrode number n, the enhancement heat transfer factor 尉 of the channel increases first, and when the number exceeds a certain value, 尉 reaches the maximum value and becomes saturated. In this paper, the maximum value of this channel is about 4.8. In this paper, the location of the electrode in the channel and the way of grounding are studied for the channel with heat flux on the top and bottom of the two walls. The results show that the heat transfer capacity of the upper and lower walls will be improved when the two electrodes in the channel are respectively close to the upper and lower walls, and when the grounding mode is partially grounded, the heat transfer capacity of the upper and lower walls will be improved. This conclusion does not change with the distance between the electrodes L and the distance d between the electrode and the entrance of the channel. When the partial grounding angle 胃 is changed, the distribution of electric potential and charge density will change, and the electric field force will also change, which leads to the corresponding changes of flow field and temperature field, and the heat transfer effect of the channel will be affected.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK124
本文编号：2153657
[Abstract]:With the development of science and technology, the integration and power of electronic products become more and more high, so the heat flux is becoming higher and higher. In order to ensure its normal operation, the thermal management of electronic products is very important. As a promising active enhanced heat transfer technology, electrohydrodynamic effect (EHD) has attracted much attention for its advantages of simple structure, low energy consumption, low noise and so on. At present, many scholars at home and abroad have carried out extensive research on EHD effect. Because of its complex mechanism, experimental research has been the majority for a long time. Only in recent decades has a numerical simulation been used to study the enhanced heat transfer induced by EHD. It is found that the influence of the transverse position of the electrode, the number of the electrode and the size of the grounding electrode on the heat transfer characteristics in the channel has not been fully studied. Based on this, the multi-physical coupling model of EHD is established, and on this basis, through the new electrode arrangement design and the optimization of related parameters, the enhancement of heat transfer characteristics in the channel is achieved. By changing the transverse position of the electrode in the channel, the traditional single-wall heat transfer channel is numerically simulated. The parameters include the position of the electrode from the entrance of the channel, the distance between the electrodes, the number of the electrodes, and so on. The numerical simulation results show that the larger the distance between the electrode and the channel is, the higher the vortex temperature is and the smaller the enhanced heat transfer factor 尉 is. The larger the electrode spacing, the smaller the interaction between the electrode and the electrode, and the greater the enhancement heat transfer factor 尉 of the channel. With the increase of electrode number n, the enhancement heat transfer factor 尉 of the channel increases first, and when the number exceeds a certain value, 尉 reaches the maximum value and becomes saturated. In this paper, the maximum value of this channel is about 4.8. In this paper, the location of the electrode in the channel and the way of grounding are studied for the channel with heat flux on the top and bottom of the two walls. The results show that the heat transfer capacity of the upper and lower walls will be improved when the two electrodes in the channel are respectively close to the upper and lower walls, and when the grounding mode is partially grounded, the heat transfer capacity of the upper and lower walls will be improved. This conclusion does not change with the distance between the electrodes L and the distance d between the electrode and the entrance of the channel. When the partial grounding angle 胃 is changed, the distribution of electric potential and charge density will change, and the electric field force will also change, which leads to the corresponding changes of flow field and temperature field, and the heat transfer effect of the channel will be affected.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK124
【参考文献】
相关期刊论文 前1条
1 邱炜;夏令志;杨兰均;张乔根;肖磊;陈立;;Experimental Study on the Velocity and Efficiency Characteristics of a Serial Staged Needle Array-Mesh Type EHD Gas Pump[J];Plasma Science and Technology;2011年06期
，本文编号：2153657
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