基于電流體動(dòng)力效應(yīng)的矩形通道內(nèi)強(qiáng)化換熱
發(fā)布時(shí)間：2018-07-29 18:47
【摘要】：隨著科技的發(fā)展,電子產(chǎn)品的集成度越來越高,功率越來越大,因此產(chǎn)生的熱流密度越來越高。為保證其正常運(yùn)行,電子產(chǎn)品的熱管理問題至關(guān)重要。作為一種頗具前景的主動(dòng)強(qiáng)化換熱技術(shù),電流體動(dòng)力效應(yīng)(electrohydrodynamics,簡(jiǎn)稱EHD)強(qiáng)化換熱以其結(jié)構(gòu)簡(jiǎn)單、能耗低、噪音小等諸多優(yōu)點(diǎn)而倍受關(guān)注。目前,國(guó)內(nèi)外很多學(xué)者已對(duì)EHD效應(yīng)進(jìn)行了廣泛研究。由于其機(jī)理復(fù)雜,長(zhǎng)期以來以實(shí)驗(yàn)研究居多。直到最近幾十年,才有學(xué)者采用數(shù)值模擬對(duì)EHD誘導(dǎo)的強(qiáng)化換熱其進(jìn)行研究。對(duì)上述研究總結(jié)歸納后發(fā)現(xiàn),目前尚未全面研究電極橫向位置、電極數(shù)目和接地電極大小的對(duì)通道內(nèi)換熱特性的影響。基于此,本文建立了EHD的多物理耦合模型,并在此基礎(chǔ)上,通過新的電極排列設(shè)計(jì)及相關(guān)參數(shù)優(yōu)化,達(dá)到增強(qiáng)通道內(nèi)強(qiáng)化換熱特性的目的。通過改變通道中電極的橫向位置對(duì)傳統(tǒng)單壁面換熱的通道進(jìn)行了數(shù)值模擬,研究參數(shù)包括電極距離通道入口的位置d,電極間距l(xiāng),電極數(shù)目n等。通過數(shù)值模擬得出,電極和通道入口距離d越大,電極所形成的漩渦溫度越高,通道的強(qiáng)化換熱因子ξ越小。電極間距l(xiāng)越大,電極和電極之間的相互影響越小,通道的強(qiáng)化換熱因子ξ越大。隨著電極數(shù)目n的增加,通道的強(qiáng)化換熱因子ξ先增大,當(dāng)數(shù)目超過一定值后ξ達(dá)到最大值并飽和。在本課題的通道中,這一最大值約為4.8。關(guān)于對(duì)上下兩個(gè)壁面都有熱流密度的通道,本課題對(duì)電極在通道中的位置和接地的方式進(jìn)行了研究。結(jié)果表明將通道中的兩個(gè)電極分別靠近上下兩個(gè)壁面,且接地方式采用部分接地時(shí),上下壁面的換熱能力都會(huì)相對(duì)有所提高,并且這一結(jié)論不會(huì)隨著電極的間距L、電極與通道入口的距離d的改變而改變。當(dāng)改變部分接地角度θ時(shí),電勢(shì)和電荷密度分布都會(huì)改變,電場(chǎng)力也隨之改變,從而導(dǎo)致流場(chǎng)和溫度場(chǎng)發(fā)生相應(yīng)的變化,通道的換熱效果會(huì)受到影響。
[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.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TK124
本文編號(hào)：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.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TK124
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 邱煒;夏令志;楊蘭均;張喬根;肖磊;陳立;;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
，本文編號(hào)：2153657
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